diff --git a/src/entities/attdef.rs b/src/entities/attdef.rs
index fbe9ba5..e81089f 100644
--- a/src/entities/attdef.rs
+++ b/src/entities/attdef.rs
@@ -161,68 +161,3 @@ fn read_tv(c: &mut BitCursor<'_>, version: Version) -> Result<String> {
         Ok(crate::code_page::decode_active(&bytes))
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn r2007_split_stream_attdef_reads_value_tag_and_prompt() {
-        let mut body = BitWriter::new();
-        text::tests::write_r2018_preamble(&mut body);
-        body.write_rc(0xFF);
-        body.write_rd(0.0);
-        body.write_rd(0.0);
-        body.write_b(true); // extrusion default
-        body.write_b(true); // thickness zero
-        body.write_rd(2.5); // height
-        body.write_rc(0); // ATTRIB's R2010+ version byte
-        body.write_rc(1); // R2018+ attribute type = single line
-        body.write_bs(0); // field length
-        body.write_rc(0x00); // flags
-        body.write_b(false); // lock position
-        body.write_rc(0); // ATTDEF's own R2010+ version byte
-        let bits = crate::string_stream::tests::bits_of(&body);
-        let payload =
-            crate::string_stream::tests::build_payload(&bits, &["1", "ATTINFO", "Enter number:"]);
-        let a = decode_modern_split_stream(&payload, 8, Version::R2018).unwrap();
-        assert_eq!(a.tag, "ATTINFO");
-        assert_eq!(a.prompt, "Enter number:");
-        assert_eq!(a.text.text, "1");
-        assert_eq!(a.text.height, 2.5);
-        assert_eq!(a.attribute_type, 1);
-        assert!(a.mtext.is_none());
-    }
-
-    #[test]
-    fn roundtrip_attdef_r2000() {
-        let mut w = BitWriter::new();
-        // TEXT preamble — minimal
-        w.write_rc(0xFF);
-        w.write_rd(0.0);
-        w.write_rd(0.0);
-        w.write_b(true);
-        w.write_b(true);
-        w.write_rd(2.5);
-        w.write_bs_u(0); // empty default text
-        // ATTRIB fields
-        w.write_bs_u(5); // tag
-        for b in b"PRICE" {
-            w.write_rc(*b);
-        }
-        w.write_bs(0); // field length
-        w.write_rc(0x00); // flags
-        // ATTDEF's own prompt, last
-        w.write_bs_u(14); // prompt
-        for b in b"Enter price: " {
-            w.write_rc(*b);
-        }
-        w.write_rc(0); // trailing NUL (stripped)
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let a = decode(&mut c, Version::R2000).unwrap();
-        assert_eq!(a.prompt, "Enter price: ");
-        assert_eq!(a.tag, "PRICE");
-    }
-}
diff --git a/src/entities/attrib.rs b/src/entities/attrib.rs
index 3439b14..4c0aafb 100644
--- a/src/entities/attrib.rs
+++ b/src/entities/attrib.rs
@@ -250,145 +250,3 @@ fn read_tv(c: &mut BitCursor<'_>, version: Version) -> Result<String> {
         Ok(crate::code_page::decode_active(&bytes))
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn r2007_split_stream_attrib_reads_value_and_tag() {
-        let mut body = BitWriter::new();
-        text::tests::write_r2018_preamble(&mut body);
-        body.write_rc(0xFF);
-        body.write_rd(0.0);
-        body.write_rd(0.0);
-        body.write_b(true); // extrusion default
-        body.write_b(true); // thickness zero
-        body.write_rd(2.5); // height
-        body.write_rc(0); // R2010+ version byte
-        body.write_rc(1); // R2018+ attribute type = single line
-        body.write_bs(0); // field length
-        body.write_rc(0x01); // flags — invisible
-        body.write_b(false); // lock position
-        let bits = crate::string_stream::tests::bits_of(&body);
-        let payload = crate::string_stream::tests::build_payload(&bits, &["17", "ATTINFO"]);
-        let a = decode_modern_split_stream(&payload, 8, Version::R2018).unwrap();
-        assert_eq!(a.tag, "ATTINFO");
-        assert_eq!(a.text.text, "17");
-        assert_eq!(a.text.height, 2.5);
-        assert_eq!(a.attribute_type, 1);
-        assert!(a.mtext.is_none());
-        assert!(a.is_invisible());
-        assert!(!a.lock_position);
-    }
-
-    /// The R2018 multi-line shape measured on `sample_AC1032.dwg`
-    /// handle `0x79D`: attribute type `2`, then a whole MTEXT record
-    /// embedded from its entity-mode bits on, then the annotative-data
-    /// size and the attribute's own flags. Its three strings are the
-    /// (empty) TEXT value, the embedded MTEXT's text, and the tag.
-    #[test]
-    fn r2018_multi_line_attrib_embeds_an_mtext() {
-        let mut body = BitWriter::new();
-        text::tests::write_r2018_preamble(&mut body);
-        body.write_rc(0xFF); // TEXT data flags: nothing optional present
-        body.write_rd(977.28); // insertion x
-        body.write_rd(27.03); // insertion y
-        body.write_b(true); // extrusion default
-        body.write_b(true); // thickness zero
-        body.write_rd(1.72); // height
-        body.write_rc(0); // R2010+ version byte
-        body.write_rc(2); // R2018+ attribute type = multi-line ATTRIB
-        // Embedded MTEXT: the common entity preamble from entmode on.
-        body.write_bb(0b00); // entmode
-        body.write_bl(0); // num reactors
-        body.write_b(true); // no xdictionary
-        body.write_b(false); // no AcDs binary data
-        body.write_bs(0); // colour
-        body.write_bd(1.0); // linetype scale
-        body.write_bb(0b00);
-        body.write_bb(0b00);
-        body.write_bb(0b00);
-        body.write_rc(0);
-        body.write_b(false);
-        body.write_b(false);
-        body.write_b(false);
-        body.write_bs(0); // invisibility
-        body.write_rc(0x1D); // lineweight
-        // Embedded MTEXT field body.
-        for v in [977.28, 28.75, 0.0] {
-            body.write_bd(v);
-        }
-        for v in [0.0, 0.0, 1.0] {
-            body.write_bd(v);
-        }
-        for v in [1.0, 0.0, 0.0] {
-            body.write_bd(v);
-        }
-        body.write_bd(0.0); // rect width
-        body.write_bd(0.0); // rect height
-        body.write_bd(1.72); // nominal text height
-        body.write_bs(1); // attachment point
-        body.write_bs(5); // drawing direction
-        body.write_bd(1.84); // extents height
-        body.write_bd(16.37); // extents width
-        body.write_bs(1); // linespace style
-        body.write_bd(1.0); // linespace factor
-        body.write_b(false); // unknown bit
-        body.write_bl(0); // background flags
-        body.write_b(false); // R2018 "is NOT annotative" — clear
-        // Back in the ATTRIB.
-        body.write_bs(0); // annotative data size
-        body.write_bs(0); // unknown 73
-        body.write_rc(0x00); // flags
-        body.write_b(true); // lock position
-
-        let bits = crate::string_stream::tests::bits_of(&body);
-        let payload = crate::string_stream::tests::build_payload(
-            &bits,
-            &["", "my multi line text for the attrrib", "MULTI_LINE_ATT"],
-        );
-        let a = decode_modern_split_stream(&payload, 8, Version::R2018).unwrap();
-        assert_eq!(a.attribute_type, 2);
-        assert_eq!(a.tag, "MULTI_LINE_ATT");
-        assert_eq!(a.text.text, "");
-        let m = a.mtext.expect("embedded MTEXT");
-        assert_eq!(m.text, "my multi line text for the attrrib");
-        assert_eq!(m.extents_width, 16.37);
-        assert!(a.lock_position);
-    }
-
-    #[test]
-    fn roundtrip_invisible_constant_attrib() {
-        let mut w = BitWriter::new();
-        // minimal TEXT payload
-        w.write_rc(0xFF);
-        w.write_rd(0.0);
-        w.write_rd(0.0);
-        w.write_b(true); // ext default
-        w.write_b(true); // thickness default
-        w.write_rd(2.5);
-        w.write_bs_u(3); // "ABC"
-        w.write_rc(b'A');
-        w.write_rc(b'B');
-        w.write_rc(b'C');
-        // attrib-specific
-        w.write_bs_u(5); // tag "PRICE"
-        w.write_rc(b'P');
-        w.write_rc(b'R');
-        w.write_rc(b'I');
-        w.write_rc(b'C');
-        w.write_rc(b'E');
-        w.write_bs(0); // field_length
-        w.write_rc(0x03); // invisible + constant
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let a = decode(&mut c, Version::R2000).unwrap();
-        assert_eq!(a.tag, "PRICE");
-        assert_eq!(a.text.text, "ABC");
-        assert!(a.is_invisible());
-        assert!(a.is_constant());
-        assert!(!a.is_verifiable());
-    }
-}
diff --git a/src/entities/block.rs b/src/entities/block.rs
index 98b3e0f..4a81e5f 100644
--- a/src/entities/block.rs
+++ b/src/entities/block.rs
@@ -85,23 +85,3 @@ pub fn decode(c: &mut BitCursor<'_>, version: Version) -> Result<Block> {
         })
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_modelspace_block_r2000() {
-        let mut w = BitWriter::new();
-        let s = b"*Model_Space";
-        w.write_bs_u(s.len() as u16);
-        for b in s {
-            w.write_rc(*b);
-        }
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let b = decode(&mut c, Version::R2000).unwrap();
-        assert_eq!(b.name, "*Model_Space");
-    }
-}
diff --git a/src/entities/body.rs b/src/entities/body.rs
index e9c7cd6..99af266 100644
--- a/src/entities/body.rs
+++ b/src/entities/body.rs
@@ -63,73 +63,3 @@ pub fn decode_record(c: &mut BitCursor<'_>, version: Version, in_data_store: boo
         tail: Some(record.tail),
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_empty_body_entity() {
-        let mut w = BitWriter::new();
-        w.write_b(true);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let b = decode(&mut c).unwrap();
-        assert!(b.acis_empty);
-        assert_eq!(b.version, None);
-        assert_eq!(b.sat_blob, None);
-    }
-
-    #[test]
-    fn roundtrip_body_with_blob() {
-        let payload = b"BODY_SAT_PAYLOAD_BYTES";
-        let mut w = BitWriter::new();
-        w.write_b(false);
-        w.write_b(false); // §20.4.41 unknown bit
-        w.write_bs_u(1);
-        w.write_bl(payload.len() as i32);
-        for x in payload {
-            w.write_rc(*x);
-        }
-        w.write_bl(0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let b = decode(&mut c).unwrap();
-        assert!(!b.acis_empty);
-        assert_eq!(b.version, Some(1));
-        assert_eq!(b.sat_blob.as_deref(), Some(&payload[..]));
-    }
-
-    /// The R2013+ data-store shape: no inline envelope, a wireframe
-    /// point, `num isolines = 4` and the 16-byte revision GUID.
-    #[test]
-    fn roundtrip_body_data_store_record() {
-        let guid = [0xCDu8; 16];
-        let mut w = BitWriter::new();
-        w.write_b(true); // wireframe data present
-        w.write_b(false); // point present
-        w.write_bl(4); // num isolines
-        w.write_b(false); // isolines present
-        w.write_b(true); // ACIS empty (2)
-        w.write_bl(0); // R2007+ unknown
-        w.write_b(true);
-        w.write_bb(0);
-        w.write_bb(0);
-        w.write_bb(0b10);
-        for b in guid {
-            w.write_rc(b);
-        }
-        w.write_bl(0);
-        let end = w.position_bits();
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let b = decode_record(&mut c, Version::R2018, true).unwrap();
-        assert!(b.in_data_store);
-        let fields = b.tail.unwrap();
-        assert_eq!(fields.num_isolines, 4);
-        assert!(!fields.isolines_present);
-        assert_eq!(fields.revision_guid, Some(guid));
-        assert_eq!(c.position_bits(), end);
-    }
-}
diff --git a/src/entities/camera.rs b/src/entities/camera.rs
index 5e621c6..8bf085b 100644
--- a/src/entities/camera.rs
+++ b/src/entities/camera.rs
@@ -65,64 +65,3 @@ pub fn decode(c: &mut BitCursor<'_>, version: Version) -> Result<Camera> {
         view_handle,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_camera_default_focal() {
-        let mut w = BitWriter::new();
-        // origin (1.0, 2.0, 3.0)
-        w.write_bd(1.0);
-        w.write_bd(2.0);
-        w.write_bd(3.0);
-        // direction (0.0, 0.0, -1.0)
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(-1.0);
-        // focal length — BD 1.0 short-form represents 1.0, so use an
-        // explicit double for 50.0mm.
-        w.write_bd(50.0);
-        // FoV ≈ 0.6 rad (about 34° full-angle, normal lens)
-        w.write_bd(0.6);
-        // view handle 5.1.0x42
-        w.write_handle(5, 0x42);
-
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let cam = decode(&mut c, Version::R2010).unwrap();
-        assert_eq!(
-            cam.origin,
-            Point3D {
-                x: 1.0,
-                y: 2.0,
-                z: 3.0
-            }
-        );
-        assert_eq!(
-            cam.direction,
-            Vec3D {
-                x: 0.0,
-                y: 0.0,
-                z: -1.0
-            }
-        );
-        assert_eq!(cam.focal_length, 50.0);
-        assert!((cam.field_of_view - 0.6).abs() < 1e-12);
-        assert_eq!(cam.view_handle.code, 5);
-        assert_eq!(cam.view_handle.value, 0x42);
-    }
-
-    #[test]
-    fn rejects_pre_r2007() {
-        let bytes = [0u8; 4];
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c, Version::R2004).unwrap_err();
-        assert!(
-            matches!(&err, Error::Unsupported { feature } if feature.contains("CAMERA")),
-            "err={err:?}"
-        );
-    }
-}
diff --git a/src/entities/dimension_aligned.rs b/src/entities/dimension_aligned.rs
index 1300819..b9250d8 100644
--- a/src/entities/dimension_aligned.rs
+++ b/src/entities/dimension_aligned.rs
@@ -61,108 +61,3 @@ pub fn decode(
         },
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::entities::dimension::read_common;
-
-    fn write_common(w: &mut BitWriter, version: Version) {
-        if version.is_r2010_plus() {
-            w.write_rc(0);
-        }
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_rd(5.0);
-        w.write_rd(5.0);
-        w.write_bd(0.0);
-        w.write_rc(0x00);
-        w.write_bs_u(0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bs(0);
-        w.write_bs(0);
-        w.write_bd(1.0);
-        w.write_bd(10.0);
-        if version.is_r2007_plus() {
-            w.write_b(false);
-            w.write_b(false);
-            w.write_b(false);
-        }
-        w.write_rd(0.0);
-        w.write_rd(0.0);
-    }
-
-    #[test]
-    fn roundtrip_aligned_r2000_no_oblique() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(5.0);
-        w.write_bd(5.0);
-        w.write_bd(0.0);
-        w.write_bd(2.5);
-        w.write_bd(2.5);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode(&mut c, &common, Version::R2000).unwrap();
-        assert_eq!(d.suffix.extension_line_2_origin.x, 5.0);
-        assert_eq!(d.suffix.extension_line_2_origin.y, 5.0);
-        assert_eq!(d.suffix.oblique_angle_radians, 0.0);
-    }
-
-    #[test]
-    fn roundtrip_aligned_with_oblique() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(7.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(4.0);
-        w.write_bd(3.0);
-        w.write_bd(0.0);
-        w.write_bd(std::f64::consts::FRAC_PI_3);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode(&mut c, &common, Version::R2000).unwrap();
-        assert!((d.suffix.oblique_angle_radians - std::f64::consts::FRAC_PI_3).abs() < 1e-12);
-        assert_eq!(d.suffix.dim_line_definition_point.y, 3.0);
-    }
-
-    #[test]
-    fn roundtrip_aligned_r2007_plus() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2007);
-        w.write_bd(2.0);
-        w.write_bd(2.0);
-        w.write_bd(0.0);
-        w.write_bd(12.0);
-        w.write_bd(2.0);
-        w.write_bd(0.0);
-        w.write_bd(7.0);
-        w.write_bd(5.0);
-        w.write_bd(0.0);
-        w.write_bd(0.25);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2007).unwrap();
-        let d = decode(&mut c, &common, Version::R2007).unwrap();
-        assert_eq!(d.suffix.extension_line_1_origin.x, 2.0);
-        assert_eq!(d.suffix.oblique_angle_radians, 0.25);
-    }
-}
diff --git a/src/entities/dimension_angular_2l.rs b/src/entities/dimension_angular_2l.rs
index 4c6d824..ee94619 100644
--- a/src/entities/dimension_angular_2l.rs
+++ b/src/entities/dimension_angular_2l.rs
@@ -56,98 +56,3 @@ pub fn decode(
         },
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::entities::dimension::read_common;
-
-    fn write_common(w: &mut BitWriter, version: Version) {
-        if version.is_r2010_plus() {
-            w.write_rc(0);
-        }
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_rd(5.0);
-        w.write_rd(5.0);
-        w.write_bd(0.0);
-        w.write_rc(0x00);
-        w.write_bs_u(0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bs(0);
-        w.write_bs(0);
-        w.write_bd(1.0);
-        w.write_bd(10.0);
-        if version.is_r2007_plus() {
-            w.write_b(false);
-            w.write_b(false);
-            w.write_b(false);
-        }
-        w.write_rd(0.0);
-        w.write_rd(0.0);
-    }
-
-    fn write_point(w: &mut BitWriter, p: (f64, f64, f64)) {
-        w.write_bd(p.0);
-        w.write_bd(p.1);
-        w.write_bd(p.2);
-    }
-
-    #[test]
-    fn roundtrip_angular_2l_perpendicular_lines() {
-        // Line 1: (0,0) → (10,0)
-        // Line 2: (0,0) → (0,10)  → perpendicular at the origin
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        write_point(&mut w, (0.0, 0.0, 0.0));
-        write_point(&mut w, (10.0, 0.0, 0.0));
-        write_point(&mut w, (0.0, 0.0, 0.0));
-        write_point(&mut w, (0.0, 10.0, 0.0));
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode(&mut c, &common, Version::R2000).unwrap();
-        assert_eq!(d.suffix.extension_line_1a.x, 0.0);
-        assert_eq!(d.suffix.extension_line_1b.x, 10.0);
-        assert_eq!(d.suffix.extension_line_2b.y, 10.0);
-    }
-
-    #[test]
-    fn roundtrip_angular_2l_arbitrary() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        write_point(&mut w, (1.0, 2.0, 3.0));
-        write_point(&mut w, (4.0, 5.0, 6.0));
-        write_point(&mut w, (7.0, 8.0, 9.0));
-        write_point(&mut w, (10.0, 11.0, 12.0));
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode(&mut c, &common, Version::R2000).unwrap();
-        assert_eq!(d.suffix.extension_line_1a.x, 1.0);
-        assert_eq!(d.suffix.extension_line_2a.y, 8.0);
-        assert_eq!(d.suffix.extension_line_2b.z, 12.0);
-    }
-
-    #[test]
-    fn roundtrip_angular_2l_r2007_plus() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2007);
-        write_point(&mut w, (0.1, 0.2, 0.3));
-        write_point(&mut w, (0.4, 0.5, 0.6));
-        write_point(&mut w, (0.7, 0.8, 0.9));
-        write_point(&mut w, (1.0, 1.1, 1.2));
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2007).unwrap();
-        let d = decode(&mut c, &common, Version::R2007).unwrap();
-        assert_eq!(d.suffix.extension_line_1b.y, 0.5);
-    }
-}
diff --git a/src/entities/dimension_angular_3p.rs b/src/entities/dimension_angular_3p.rs
index 7e7c505..111c628 100644
--- a/src/entities/dimension_angular_3p.rs
+++ b/src/entities/dimension_angular_3p.rs
@@ -51,108 +51,3 @@ pub fn decode(
         },
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::entities::dimension::read_common;
-
-    fn write_common(w: &mut BitWriter, version: Version) {
-        if version.is_r2010_plus() {
-            w.write_rc(0);
-        }
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_rd(5.0);
-        w.write_rd(5.0);
-        w.write_bd(0.0);
-        w.write_rc(0x00);
-        w.write_bs_u(0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bs(0);
-        w.write_bs(0);
-        w.write_bd(1.0);
-        w.write_bd(10.0);
-        if version.is_r2007_plus() {
-            w.write_b(false);
-            w.write_b(false);
-            w.write_b(false);
-        }
-        w.write_rd(0.0);
-        w.write_rd(0.0);
-    }
-
-    #[test]
-    fn roundtrip_angular_3p_right_angle() {
-        // Right angle at the origin between +x and +y axes.
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0); // center
-        w.write_bd(10.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0); // first extension
-        w.write_bd(0.0);
-        w.write_bd(10.0);
-        w.write_bd(0.0); // second extension
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode(&mut c, &common, Version::R2000).unwrap();
-        assert_eq!(d.suffix.center.x, 0.0);
-        assert_eq!(d.suffix.first_extension_point.x, 10.0);
-        assert_eq!(d.suffix.second_extension_point.y, 10.0);
-    }
-
-    #[test]
-    fn roundtrip_angular_3p_offset_center() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        w.write_bd(5.0);
-        w.write_bd(5.0);
-        w.write_bd(0.0);
-        w.write_bd(15.0);
-        w.write_bd(5.0);
-        w.write_bd(0.0);
-        w.write_bd(5.0);
-        w.write_bd(15.0);
-        w.write_bd(0.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode(&mut c, &common, Version::R2000).unwrap();
-        assert_eq!(d.suffix.center.x, 5.0);
-        assert_eq!(d.suffix.center.y, 5.0);
-        assert_eq!(d.suffix.first_extension_point.x, 15.0);
-    }
-
-    #[test]
-    fn roundtrip_angular_3p_r2010() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2010);
-        w.write_bd(1.0);
-        w.write_bd(2.0);
-        w.write_bd(3.0);
-        w.write_bd(4.0);
-        w.write_bd(5.0);
-        w.write_bd(6.0);
-        w.write_bd(7.0);
-        w.write_bd(8.0);
-        w.write_bd(9.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2010).unwrap();
-        let d = decode(&mut c, &common, Version::R2010).unwrap();
-        assert_eq!(d.suffix.center.z, 3.0);
-        assert_eq!(d.suffix.first_extension_point.y, 5.0);
-        assert_eq!(d.suffix.second_extension_point.x, 7.0);
-    }
-}
diff --git a/src/entities/dimension_diameter.rs b/src/entities/dimension_diameter.rs
index fc8f1bf..0679fb1 100644
--- a/src/entities/dimension_diameter.rs
+++ b/src/entities/dimension_diameter.rs
@@ -18,73 +18,3 @@
 pub use crate::entities::dimension_radial::{
     DimensionDiameter, DimensionRadialSuffix, decode_diameter as decode,
 };
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitcursor::BitCursor;
-    use crate::bitwriter::BitWriter;
-    use crate::entities::dimension::read_common;
-    use crate::version::Version;
-
-    fn write_common(w: &mut BitWriter, version: Version) {
-        if version.is_r2010_plus() {
-            w.write_rc(0);
-        }
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_rd(5.0);
-        w.write_rd(5.0);
-        w.write_bd(0.0);
-        w.write_rc(0x00);
-        w.write_bs_u(0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bs(0);
-        w.write_bs(0);
-        w.write_bd(1.0);
-        w.write_bd(10.0);
-        if version.is_r2007_plus() {
-            w.write_b(false);
-            w.write_b(false);
-            w.write_b(false);
-        }
-        w.write_rd(0.0);
-        w.write_rd(0.0);
-    }
-
-    #[test]
-    fn decode_via_reexport() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(12.5);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(6.25);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d: DimensionDiameter = decode(&mut c, &common, Version::R2000).unwrap();
-        assert_eq!(d.suffix.first_arc_point.x, 12.5);
-        assert_eq!(d.suffix.leader_length, 6.25);
-    }
-
-    #[test]
-    fn suffix_shape_matches_radial() {
-        // Sanity-check the re-export — the public type is the one
-        // declared in dimension_radial, not a duplicate.
-        let _s: DimensionRadialSuffix = DimensionRadialSuffix {
-            center_point: crate::entities::Point3D::default(),
-            first_arc_point: crate::entities::Point3D::default(),
-            leader_length: 0.0,
-        };
-    }
-}
diff --git a/src/entities/dimension_linear.rs b/src/entities/dimension_linear.rs
index 06cb7b6..583127e 100644
--- a/src/entities/dimension_linear.rs
+++ b/src/entities/dimension_linear.rs
@@ -79,113 +79,3 @@ pub fn decode(
         },
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::entities::dimension::read_common;
-
-    /// Write a minimal common dimension preamble matching the test
-    /// helper in `dimension.rs`.
-    fn write_common(w: &mut BitWriter, version: Version) {
-        if version.is_r2010_plus() {
-            w.write_rc(0);
-        }
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0); // extrusion
-        w.write_rd(5.0);
-        w.write_rd(5.0); // text midpoint
-        w.write_bd(0.0); // elevation
-        w.write_rc(0x00); // flags
-        w.write_bs_u(0); // empty user text
-        w.write_bd(0.0); // text rotation
-        w.write_bd(0.0); // horiz dir
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0); // ins scale
-        w.write_bd(0.0); // ins rotation
-        w.write_bs(0); // attachment
-        w.write_bs(0); // line-spacing style
-        w.write_bd(1.0); // line-spacing factor
-        w.write_bd(10.0); // actual measurement
-        if version.is_r2007_plus() {
-            w.write_b(false);
-            w.write_b(false);
-            w.write_b(false);
-        }
-        w.write_rd(0.0);
-        w.write_rd(0.0); // def point 12
-    }
-
-    #[test]
-    fn roundtrip_linear_r2000_basic() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0); // ext line 1
-        w.write_bd(10.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0); // ext line 2
-        w.write_bd(5.0);
-        w.write_bd(2.0);
-        w.write_bd(0.0); // dim line def point
-        w.write_bd(0.0); // rotation
-        w.write_bd(0.0); // oblique
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode(&mut c, &common, Version::R2000).unwrap();
-        assert_eq!(d.suffix.extension_line_2_origin.x, 10.0);
-        assert_eq!(d.suffix.dim_line_definition_point.y, 2.0);
-        assert_eq!(d.suffix.rotation_radians, 0.0);
-    }
-
-    #[test]
-    fn roundtrip_linear_r2000_rotated() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        w.write_bd(1.0);
-        w.write_bd(2.0);
-        w.write_bd(3.0);
-        w.write_bd(11.0);
-        w.write_bd(2.0);
-        w.write_bd(3.0);
-        w.write_bd(6.0);
-        w.write_bd(4.0);
-        w.write_bd(3.0);
-        w.write_bd(std::f64::consts::FRAC_PI_4);
-        w.write_bd(std::f64::consts::FRAC_PI_6);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode(&mut c, &common, Version::R2000).unwrap();
-        assert!((d.suffix.rotation_radians - std::f64::consts::FRAC_PI_4).abs() < 1e-12);
-        assert!((d.suffix.oblique_angle_radians - std::f64::consts::FRAC_PI_6).abs() < 1e-12);
-        assert_eq!(d.suffix.extension_line_1_origin.x, 1.0);
-    }
-
-    #[test]
-    fn roundtrip_linear_r2010_version_gate() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2010);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.5);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2010).unwrap();
-        let d = decode(&mut c, &common, Version::R2010).unwrap();
-        assert_eq!(d.suffix.extension_line_2_origin.x, 1.0);
-    }
-}
diff --git a/src/entities/dimension_ordinate.rs b/src/entities/dimension_ordinate.rs
index c642152..198a8f6 100644
--- a/src/entities/dimension_ordinate.rs
+++ b/src/entities/dimension_ordinate.rs
@@ -78,106 +78,3 @@ pub fn decode(
         },
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::entities::dimension::read_common;
-
-    fn write_common(w: &mut BitWriter, version: Version) {
-        if version.is_r2010_plus() {
-            w.write_rc(0);
-        }
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_rd(5.0);
-        w.write_rd(5.0);
-        w.write_bd(0.0);
-        w.write_rc(0x00);
-        w.write_bs_u(0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bs(0);
-        w.write_bs(0);
-        w.write_bd(1.0);
-        w.write_bd(10.0);
-        if version.is_r2007_plus() {
-            w.write_b(false);
-            w.write_b(false);
-            w.write_b(false);
-        }
-        w.write_rd(0.0);
-        w.write_rd(0.0);
-    }
-
-    #[test]
-    fn roundtrip_ordinate_y_type() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        w.write_bd(3.0);
-        w.write_bd(4.0);
-        w.write_bd(0.0); // feature
-        w.write_bd(3.0);
-        w.write_bd(10.0);
-        w.write_bd(0.0); // leader
-        w.write_rc(0x00); // Y-type flag
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode(&mut c, &common, Version::R2000).unwrap();
-        assert_eq!(d.suffix.feature_location.x, 3.0);
-        assert_eq!(d.suffix.feature_location.y, 4.0);
-        assert_eq!(d.suffix.leader_endpoint.y, 10.0);
-        assert_eq!(d.suffix.flags, 0x00);
-        assert_eq!(d.suffix.axis(), OrdinateAxis::Y);
-    }
-
-    #[test]
-    fn roundtrip_ordinate_x_type() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        w.write_bd(5.0);
-        w.write_bd(2.0);
-        w.write_bd(0.0);
-        w.write_bd(12.0);
-        w.write_bd(2.0);
-        w.write_bd(0.0);
-        w.write_rc(0x01); // X-type flag
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode(&mut c, &common, Version::R2000).unwrap();
-        assert_eq!(d.suffix.feature_location.x, 5.0);
-        assert_eq!(d.suffix.leader_endpoint.x, 12.0);
-        assert_eq!(d.suffix.flags, 0x01);
-        assert_eq!(d.suffix.axis(), OrdinateAxis::X);
-    }
-
-    #[test]
-    fn ordinate_flag_reserved_bits_preserved() {
-        // Ensure higher-order flag bits survive round-trip — they
-        // are ODA-reserved, so we preserve them even though we don't
-        // interpret them.
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_rc(0xF1); // x-type, plus high reserved bits
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode(&mut c, &common, Version::R2000).unwrap();
-        assert_eq!(d.suffix.flags, 0xF1);
-        assert_eq!(d.suffix.axis(), OrdinateAxis::X);
-    }
-}
diff --git a/src/entities/dimension_radial.rs b/src/entities/dimension_radial.rs
index 959f699..610245b 100644
--- a/src/entities/dimension_radial.rs
+++ b/src/entities/dimension_radial.rs
@@ -89,103 +89,3 @@ fn read_suffix(c: &mut BitCursor<'_>) -> Result<DimensionRadialSuffix> {
         leader_length,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::entities::dimension::read_common;
-
-    fn write_common(w: &mut BitWriter, version: Version) {
-        if version.is_r2010_plus() {
-            w.write_rc(0);
-        }
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_rd(5.0);
-        w.write_rd(5.0);
-        w.write_bd(0.0);
-        w.write_rc(0x00);
-        w.write_bs_u(0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bs(0);
-        w.write_bs(0);
-        w.write_bd(1.0);
-        w.write_bd(10.0);
-        if version.is_r2007_plus() {
-            w.write_b(false);
-            w.write_b(false);
-            w.write_b(false);
-        }
-        w.write_rd(0.0);
-        w.write_rd(0.0);
-    }
-
-    fn write_radial_suffix(w: &mut BitWriter, cp: (f64, f64, f64), fap: (f64, f64, f64), ll: f64) {
-        w.write_bd(cp.0);
-        w.write_bd(cp.1);
-        w.write_bd(cp.2);
-        w.write_bd(fap.0);
-        w.write_bd(fap.1);
-        w.write_bd(fap.2);
-        w.write_bd(ll);
-    }
-
-    #[test]
-    fn roundtrip_radius_r2000() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        write_radial_suffix(&mut w, (0.0, 0.0, 0.0), (5.0, 0.0, 0.0), 2.5);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode_radius(&mut c, &common, Version::R2000).unwrap();
-        assert_eq!(d.suffix.center_point.x, 0.0);
-        assert_eq!(d.suffix.first_arc_point.x, 5.0);
-        assert_eq!(d.suffix.leader_length, 2.5);
-    }
-
-    #[test]
-    fn roundtrip_diameter_r2000() {
-        let mut w = BitWriter::new();
-        write_common(&mut w, Version::R2000);
-        write_radial_suffix(&mut w, (10.0, 10.0, 0.0), (20.0, 10.0, 0.0), 4.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let common = read_common(&mut c, Version::R2000).unwrap();
-        let d = decode_diameter(&mut c, &common, Version::R2000).unwrap();
-        assert_eq!(d.suffix.center_point.x, 10.0);
-        assert_eq!(d.suffix.first_arc_point.x, 20.0);
-        assert_eq!(d.suffix.leader_length, 4.0);
-    }
-
-    #[test]
-    fn radius_and_diameter_share_layout() {
-        // Two identical streams should decode to identical suffixes.
-        let mut w1 = BitWriter::new();
-        write_common(&mut w1, Version::R2000);
-        write_radial_suffix(&mut w1, (1.0, 2.0, 0.0), (4.0, 2.0, 0.0), 0.5);
-        let bytes1 = w1.into_bytes();
-
-        let mut w2 = BitWriter::new();
-        write_common(&mut w2, Version::R2000);
-        write_radial_suffix(&mut w2, (1.0, 2.0, 0.0), (4.0, 2.0, 0.0), 0.5);
-        let bytes2 = w2.into_bytes();
-
-        let mut c1 = BitCursor::new(&bytes1);
-        let common1 = read_common(&mut c1, Version::R2000).unwrap();
-        let r = decode_radius(&mut c1, &common1, Version::R2000).unwrap();
-
-        let mut c2 = BitCursor::new(&bytes2);
-        let common2 = read_common(&mut c2, Version::R2000).unwrap();
-        let d = decode_diameter(&mut c2, &common2, Version::R2000).unwrap();
-
-        assert_eq!(r.suffix, d.suffix);
-    }
-}
diff --git a/src/entities/ellipse.rs b/src/entities/ellipse.rs
index 404b196..f7d155a 100644
--- a/src/entities/ellipse.rs
+++ b/src/entities/ellipse.rs
@@ -47,35 +47,3 @@ pub fn decode(c: &mut BitCursor<'_>) -> Result<Ellipse> {
         end_param,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_ellipse() {
-        let mut w = BitWriter::new();
-        // center
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        // major axis (10, 0, 0)
-        w.write_bd(10.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        // extrusion (0, 0, 1)
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        // axis_ratio
-        w.write_bd(0.5);
-        w.write_bd(0.0);
-        w.write_bd(std::f64::consts::TAU);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let e = decode(&mut c).unwrap();
-        assert_eq!(e.axis_ratio, 0.5);
-        assert_eq!(e.major_axis.x, 10.0);
-    }
-}
diff --git a/src/entities/endblk.rs b/src/entities/endblk.rs
index 6ddbe80..8e7baa3 100644
--- a/src/entities/endblk.rs
+++ b/src/entities/endblk.rs
@@ -15,16 +15,3 @@ pub struct EndBlk;
 pub fn decode(_c: &mut BitCursor<'_>) -> Result<EndBlk> {
     Ok(EndBlk)
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn endblk_is_empty() {
-        // Any cursor position is valid since there's nothing to read.
-        let buf: [u8; 0] = [];
-        let mut c = BitCursor::new(&buf);
-        let _ = decode(&mut c).unwrap();
-    }
-}
diff --git a/src/entities/extruded_surface.rs b/src/entities/extruded_surface.rs
index 761ccff..70bf886 100644
--- a/src/entities/extruded_surface.rs
+++ b/src/entities/extruded_surface.rs
@@ -55,67 +55,3 @@ pub fn decode(c: &mut BitCursor<'_>) -> Result<ExtrudedSurface> {
         draft_angle,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::entities::modeler::tests::write_sat_blob;
-
-    #[test]
-    fn roundtrip_extruded_surface_with_blob() {
-        let mut w = BitWriter::new();
-        let blob = SatBlob {
-            empty: false,
-            version: 1,
-            bytes: b"DUMMY SAT BYTES".to_vec(),
-        };
-        write_sat_blob(&mut w, &blob);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(10.0); // sweep +Z, 10 units
-        w.write_bd(0.1_f64); // draft
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let s = decode(&mut c).unwrap();
-        assert_eq!(s.sat, blob);
-        assert_eq!(
-            s.sweep_vector,
-            Vec3D {
-                x: 0.0,
-                y: 0.0,
-                z: 10.0
-            }
-        );
-        assert!((s.draft_angle - 0.1).abs() < 1e-12);
-    }
-
-    #[test]
-    fn roundtrip_extruded_surface_empty_blob() {
-        let mut w = BitWriter::new();
-        write_sat_blob(
-            &mut w,
-            &SatBlob {
-                empty: true,
-                version: 0,
-                bytes: Vec::new(),
-            },
-        );
-        w.write_bd(1.0);
-        w.write_bd(2.0);
-        w.write_bd(3.0);
-        w.write_bd(0.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let s = decode(&mut c).unwrap();
-        assert!(s.sat.empty);
-        assert_eq!(
-            s.sweep_vector,
-            Vec3D {
-                x: 1.0,
-                y: 2.0,
-                z: 3.0
-            }
-        );
-    }
-}
diff --git a/src/entities/hatch.rs b/src/entities/hatch.rs
index fffe5be..46e6285 100644
--- a/src/entities/hatch.rs
+++ b/src/entities/hatch.rs
@@ -617,352 +617,3 @@ fn decode_pattern_line(c: &mut BitCursor<'_>) -> Result<PatternLine> {
 
 /// Back-compat alias. Prefer [`decode`].
 pub use decode as decode_header;
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::string_stream::tests::{bits_of, build_payload};
-
-    /// Write the R2004+ gradient block. §20.4.75 writes it on every
-    /// R2004+ HATCH, gradient or not — the flag only says whether the
-    /// hatch *uses* it.
-    fn write_gradient_block(w: &mut BitWriter, is_gradient: u32, colors: &[(f64, u32)]) {
-        w.write_bl(is_gradient as i32);
-        w.write_bl(0); // reserved
-        w.write_bd(45.0); // angle
-        w.write_bd(0.5); // shift
-        w.write_bl(1); // single colour
-        w.write_bd(0.75); // tint
-        w.write_bl(colors.len() as i32);
-        for (unknown, rgb) in colors {
-            w.write_bd(*unknown);
-            w.write_bs(0);
-            w.write_bl(*rgb as i32);
-            w.write_rc(0);
-        }
-        // The gradient name `TV` slot; inline on pre-R2007.
-        w.write_bs_u(0);
-    }
-
-    fn write_tv_8bit(w: &mut BitWriter, bytes: &[u8]) {
-        w.write_bs_u(bytes.len() as u16);
-        for b in bytes {
-            w.write_rc(*b);
-        }
-    }
-
-    /// Header of a non-gradient R2004 HATCH up to `num_paths`.
-    fn write_hatch_header(w: &mut BitWriter, pattern_name: &[u8], solid_fill: bool) {
-        write_gradient_block(w, 0, &[]);
-        w.write_bd(0.0); // elevation
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0); // extrusion (0,0,1)
-        write_tv_8bit(w, pattern_name);
-        w.write_b(solid_fill);
-        w.write_b(false); // associative
-    }
-
-    /// Tail of a solid-fill hatch: style, pattern type, no pixel size
-    /// (no path has the derived bit), no seed points.
-    fn write_solid_tail(w: &mut BitWriter) {
-        w.write_bs_u(0); // style
-        w.write_bs_u(1); // pattern type
-        w.write_bl(0); // num seed points
-    }
-
-    #[test]
-    fn roundtrip_solid_fill_no_paths() {
-        let mut w = BitWriter::new();
-        write_hatch_header(&mut w, b"SOLID", true);
-        w.write_bl(0); // 0 paths
-        write_solid_tail(&mut w);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let h = decode(&mut c, Version::R2004).unwrap();
-        assert_eq!(h.pattern_name, "SOLID");
-        assert!(h.solid_fill);
-        assert!(!h.associative);
-        assert!(h.paths.is_empty());
-        assert!(h.gradient.is_none());
-        assert!(h.pattern_lines.is_empty());
-        assert!(h.seed_points.is_empty());
-        assert_eq!(h.pattern_type, 1);
-    }
-
-    #[test]
-    fn roundtrip_polyline_path() {
-        let mut w = BitWriter::new();
-        write_hatch_header(&mut w, b"ANSI31", true);
-        w.write_bl(1); // 1 path
-        w.write_bl_u(0x02 | 0x10); // polyline + outermost
-        w.write_b(false); // has_bulge
-        w.write_b(true); // is_closed
-        w.write_bl(3); // num vertices
-        for (x, y) in [(0.0f64, 0.0), (10.0, 0.0), (10.0, 10.0)] {
-            w.write_rd(x);
-            w.write_rd(y);
-        }
-        w.write_bl(0); // num boundary handles
-        write_solid_tail(&mut w);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let h = decode(&mut c, Version::R2004).unwrap();
-        assert_eq!(h.paths.len(), 1);
-        assert_eq!(h.paths[0].flags, 0x12);
-        assert_eq!(h.paths[0].num_boundary_handles, 0);
-        match &h.paths[0].segments {
-            HatchPathSegments::Polyline {
-                has_bulge,
-                is_closed,
-                vertices,
-            } => {
-                assert!(!has_bulge);
-                assert!(is_closed);
-                assert_eq!(vertices.len(), 3);
-                assert_eq!(vertices[0].0, Point2D { x: 0.0, y: 0.0 });
-                assert_eq!(vertices[2].0, Point2D { x: 10.0, y: 10.0 });
-                assert!(vertices[0].1.is_none());
-            }
-            other => panic!("expected Polyline, got {other:?}"),
-        }
-    }
-
-    #[test]
-    fn roundtrip_line_edge_path() {
-        let mut w = BitWriter::new();
-        write_hatch_header(&mut w, b"ANSI31", true);
-        w.write_bl(1); // 1 path
-        w.write_bl_u(0x01); // external (edge list)
-        w.write_bl(4); // 4 edges
-        let square = [
-            ((0.0f64, 0.0), (10.0, 0.0)),
-            ((10.0, 0.0), (10.0, 10.0)),
-            ((10.0, 10.0), (0.0, 10.0)),
-            ((0.0, 10.0), (0.0, 0.0)),
-        ];
-        for ((sx, sy), (ex, ey)) in square {
-            w.write_rc(1); // line
-            w.write_rd(sx);
-            w.write_rd(sy);
-            w.write_rd(ex);
-            w.write_rd(ey);
-        }
-        w.write_bl(2); // num boundary handles — the handles are in the handle stream
-        write_solid_tail(&mut w);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let h = decode(&mut c, Version::R2004).unwrap();
-        assert_eq!(h.paths.len(), 1);
-        assert_eq!(h.paths[0].num_boundary_handles, 2);
-        match &h.paths[0].segments {
-            HatchPathSegments::Edges(edges) => {
-                assert_eq!(edges.len(), 4);
-                match &edges[0] {
-                    HatchEdge::Line { start, end } => {
-                        assert_eq!(*start, Point2D { x: 0.0, y: 0.0 });
-                        assert_eq!(*end, Point2D { x: 10.0, y: 0.0 });
-                    }
-                    other => panic!("expected Line, got {other:?}"),
-                }
-                match &edges[3] {
-                    HatchEdge::Line { start, end } => {
-                        assert_eq!(*start, Point2D { x: 0.0, y: 10.0 });
-                        assert_eq!(*end, Point2D { x: 0.0, y: 0.0 });
-                    }
-                    other => panic!("expected Line, got {other:?}"),
-                }
-            }
-            other => panic!("expected Edges, got {other:?}"),
-        }
-    }
-
-    #[test]
-    fn decode_errors_on_oversized_paths() {
-        let mut w = BitWriter::new();
-        write_hatch_header(&mut w, b"SOLID", true);
-        w.write_bl(20_000); // over cap
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c, Version::R2004).unwrap_err();
-        assert!(
-            matches!(&err, Error::SectionMap(msg) if msg.contains("num_paths")),
-            "err={err:?}"
-        );
-    }
-
-    #[test]
-    fn decode_errors_on_oversized_segs() {
-        let mut w = BitWriter::new();
-        write_hatch_header(&mut w, b"SOLID", true);
-        w.write_bl(1); // 1 path
-        w.write_bl_u(0x01); // edge path
-        w.write_bl(200_000); // over cap
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c, Version::R2004).unwrap_err();
-        assert!(
-            matches!(&err, Error::SectionMap(msg) if msg.contains("num_path_segs")),
-            "err={err:?}"
-        );
-    }
-
-    #[test]
-    fn roundtrip_gradient_fill() {
-        let mut w = BitWriter::new();
-        write_gradient_block(&mut w, 1, &[(0.0, 0x00FF_0000), (1.0, 0x0000_00FF)]);
-        w.write_bd(0.0); // elevation
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0); // extrusion
-        write_tv_8bit(&mut w, b"SOLID");
-        w.write_b(true); // solid fill
-        w.write_b(false); // associative
-        w.write_bl(0); // 0 paths
-        write_solid_tail(&mut w);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let h = decode(&mut c, Version::R2004).unwrap();
-        let g = h.gradient.expect("gradient should be present");
-        assert_eq!(g.angle, 45.0);
-        assert_eq!(g.shift, 0.5);
-        assert_eq!(g.is_single_color, 1);
-        assert_eq!(g.tint, 0.75);
-        assert_eq!(g.colors.len(), 2);
-        assert_eq!(g.colors[0].rgb, 0x00FF_0000);
-        assert_eq!(g.colors[1].rgb, 0x0000_00FF);
-    }
-
-    /// A non-solid hatch writes the pattern-definition block; a derived
-    /// path (`pathflag & 4`) adds the `BD` pixel size.
-    #[test]
-    fn roundtrip_pattern_lines_and_seed_points() {
-        let mut w = BitWriter::new();
-        write_hatch_header(&mut w, b"ANSI31", false);
-        w.write_bl(1); // one path
-        w.write_bl_u(0x04); // derived path → pixel size is written
-        w.write_bl(0); // no edges
-        w.write_bl(0); // no boundary handles
-        w.write_bs_u(1); // style
-        w.write_bs_u(1); // pattern type
-        w.write_bd(45.0); // pattern angle
-        w.write_bd(2.0); // pattern scale
-        w.write_b(false); // pattern double
-        w.write_bs_u(2); // num pattern lines
-        w.write_bd(0.0); // line 0 angle
-        w.write_bd(0.0);
-        w.write_bd(0.0); // origin
-        w.write_bd(1.0);
-        w.write_bd(0.0); // offset
-        w.write_bs_u(2);
-        w.write_bd(1.0);
-        w.write_bd(-0.5);
-        w.write_bd(90.0); // line 1 angle
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bs_u(0);
-        w.write_bd(4.0); // pixel size
-        w.write_bl(1); // one seed point
-        w.write_rd(5.0);
-        w.write_rd(5.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let h = decode(&mut c, Version::R2004).unwrap();
-        assert_eq!(h.pattern_style, 1);
-        assert_eq!(h.pattern_angle, 45.0);
-        assert_eq!(h.pattern_scale, 2.0);
-        assert_eq!(h.pattern_lines.len(), 2);
-        assert_eq!(h.pattern_lines[0].dashes, vec![1.0, -0.5]);
-        assert_eq!(h.pattern_lines[0].angle, 0.0);
-        assert_eq!(h.pattern_lines[1].angle, 90.0);
-        assert!(h.pattern_lines[1].dashes.is_empty());
-        assert_eq!(h.pixel_size, 4.0);
-        assert_eq!(h.seed_points.len(), 1);
-        assert_eq!(h.seed_points[0], (5.0, 5.0));
-    }
-
-    /// The R2018 shape: two strings in the string stream — the gradient
-    /// name and then the pattern name — even on a hatch whose gradient
-    /// flag is clear, and the data fields ending exactly on the
-    /// string-stream start bit.
-    #[test]
-    fn r2018_split_stream_hatch_reads_both_names() {
-        let mut w = BitWriter::new();
-        w.write_bs_u(0); // no XDATA
-        w.write_b(false); // no graphics preview
-        w.write_bb(0b10);
-        w.write_bl(0);
-        w.write_b(true);
-        w.write_b(false);
-        w.write_bs_u(0x0100);
-        w.write_bd(1.0);
-        w.write_bb(0b00);
-        w.write_bb(0b00);
-        w.write_bb(0b00);
-        w.write_rc(0);
-        w.write_b(false);
-        w.write_b(false);
-        w.write_b(false);
-        w.write_bs(0);
-        w.write_rc(0x1D);
-        // Gradient block with the flag clear — the `TV` slot consumes
-        // no data bits on R2007+.
-        w.write_bl(0);
-        w.write_bl(0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bl(0);
-        w.write_bd(0.0);
-        w.write_bl(0);
-        w.write_bd(0.0); // elevation
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0); // extrusion, as the sample writes it
-        w.write_b(true); // solid fill
-        w.write_b(false); // associative
-        w.write_bl(0); // no paths
-        w.write_bs_u(0); // style
-        w.write_bs_u(1); // pattern type
-        w.write_bl(0); // no seed points
-        let body = bits_of(&w);
-        let payload = build_payload(&body, &["LINEAR", "ANSI31"]);
-        let h = decode_modern_split_stream(&payload, 8, Version::R2018).unwrap();
-        assert!(h.gradient.is_none());
-        assert_eq!(h.pattern_name, "ANSI31");
-        assert!(h.solid_fill);
-        assert_eq!(h.pattern_type, 1);
-    }
-
-    /// The clear-flag early return this decoder used to take consumed
-    /// one `TV` too few, so the pattern name came back as the gradient
-    /// name and the record misaligned. Guard against the regression.
-    #[test]
-    fn r2018_clear_gradient_flag_still_consumes_the_gradient_name() {
-        let mut w = BitWriter::new();
-        w.write_bl(0); // gradient flag clear
-        w.write_bl(0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bl(0);
-        w.write_bd(0.0);
-        w.write_bl(0);
-        write_tv_8bit(&mut w, b"LINEAR"); // gradient name, inline on R2004
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        write_tv_8bit(&mut w, b"ANSI31");
-        w.write_b(true);
-        w.write_b(false);
-        w.write_bl(0);
-        write_solid_tail(&mut w);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let h = decode(&mut c, Version::R2004).unwrap();
-        assert!(h.gradient.is_none());
-        assert_eq!(h.pattern_name, "ANSI31");
-    }
-}
diff --git a/src/entities/helix.rs b/src/entities/helix.rs
index 51f0b65..1d2431c 100644
--- a/src/entities/helix.rs
+++ b/src/entities/helix.rs
@@ -103,94 +103,3 @@ pub fn decode(c: &mut BitCursor<'_>) -> Result<Helix> {
         constrain_type,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_right_handed_helix() {
-        let mut w = BitWriter::new();
-        // axis base at origin
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        // start at (radius, 0, 0)
-        w.write_bd(5.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        // axis +Z
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        // radius 5
-        w.write_bd(5.0);
-        // 3 turns
-        w.write_bd(3.0);
-        // turn height 2 (total height 6)
-        w.write_bd(2.0);
-        // right-handed
-        w.write_b(true);
-        // constrain by turn-height
-        w.write_bs(0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let h = decode(&mut c).unwrap();
-        assert_eq!(h.axis_base_point, Point3D::default());
-        assert_eq!(
-            h.start_point,
-            Point3D {
-                x: 5.0,
-                y: 0.0,
-                z: 0.0
-            }
-        );
-        assert!((h.radius - 5.0).abs() < 1e-12);
-        assert!((h.turns - 3.0).abs() < 1e-12);
-        assert!(h.right_handed);
-        assert_eq!(h.constrain_type, ConstrainType::TurnHeight);
-    }
-
-    #[test]
-    fn roundtrip_left_handed_fractional_turns() {
-        let mut w = BitWriter::new();
-        for _ in 0..3 {
-            // three points, no origin shift for simplicity
-            w.write_bd(1.0);
-            w.write_bd(2.0);
-            w.write_bd(3.0);
-        }
-        w.write_bd(2.5); // radius
-        w.write_bd(1.25); // turns — fractional
-        w.write_bd(1.0); // turn height
-        w.write_b(false); // left-handed
-        w.write_bs(2); // constrain by height
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let h = decode(&mut c).unwrap();
-        assert!(!h.right_handed);
-        assert!((h.turns - 1.25).abs() < 1e-12);
-        assert_eq!(h.constrain_type, ConstrainType::Height);
-    }
-
-    #[test]
-    fn rejects_bad_constrain_enum() {
-        assert!(ConstrainType::from_bs(3).is_err());
-        assert!(matches!(
-            ConstrainType::from_bs(-1).unwrap_err(),
-            Error::SectionMap(_)
-        ));
-    }
-
-    #[test]
-    fn constrain_type_roundtrip() {
-        for ct in [
-            ConstrainType::TurnHeight,
-            ConstrainType::Turns,
-            ConstrainType::Height,
-        ] {
-            assert_eq!(ConstrainType::from_bs(ct.to_bs()).unwrap(), ct);
-        }
-    }
-}
diff --git a/src/entities/image.rs b/src/entities/image.rs
index 0eb5a5e..5be66a4 100644
--- a/src/entities/image.rs
+++ b/src/entities/image.rs
@@ -156,128 +156,3 @@ pub fn decode(c: &mut BitCursor<'_>, version: Version) -> Result<Image> {
         clip_boundary,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_image_with_rect_clip() {
-        let mut w = BitWriter::new();
-        w.write_bl(0);
-        w.write_bd(10.0);
-        w.write_bd(20.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_rd(1920.0);
-        w.write_rd(1080.0);
-        w.write_bs(0x07); // show + show-not-aligned + clip
-        w.write_b(true); // clipping
-        w.write_rc(50);
-        w.write_rc(50);
-        w.write_rc(0);
-        w.write_bs(1); // rectangle — no vertex count follows
-        w.write_rd(0.0);
-        w.write_rd(0.0);
-        w.write_rd(1920.0);
-        w.write_rd(1080.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let i = decode(&mut c, Version::R2000).unwrap();
-        assert_eq!(
-            i.image_size,
-            Point2D {
-                x: 1920.0,
-                y: 1080.0
-            }
-        );
-        assert!(matches!(i.clip_boundary, ClipBoundary::Rectangle { .. }));
-    }
-
-    /// The measured `sample_AC1032.dwg` IMAGE body (handle `0x662`):
-    /// a 994 × 965 raster whose rectangular clip boundary follows the
-    /// boundary type with no vertex count in between.
-    #[test]
-    fn decodes_the_measured_rectangle_image_body() {
-        let mut w = BitWriter::new();
-        w.write_bl(0);
-        w.write_bd(0.0); // insertion point (0, 15, 0)
-        w.write_bd(15.0);
-        w.write_bd(0.0);
-        w.write_bd(0.010416666666666664); // u vector = 1/96 in X
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(6.37836874555913e-19); // v vector = 1/96 in Y
-        w.write_bd(0.010416666666666666);
-        w.write_bd(0.0);
-        w.write_rd(994.0); // image size in pixels
-        w.write_rd(965.0);
-        w.write_bs(7); // display flags
-        w.write_b(false); // clipping off
-        w.write_rc(50);
-        w.write_rc(50);
-        w.write_rc(0);
-        w.write_b(false); // clip mode (R2010+)
-        w.write_bs(1); // rectangle
-        w.write_rd(-0.5); // corners, straight after the type
-        w.write_rd(-0.5);
-        w.write_rd(993.5);
-        w.write_rd(964.5);
-        let end = w.position_bits();
-
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let i = decode(&mut c, Version::R2018).unwrap();
-        assert_eq!(i.image_size, Point2D { x: 994.0, y: 965.0 });
-        assert_eq!(i.brightness, 50);
-        assert_eq!(
-            i.clip_boundary,
-            ClipBoundary::Rectangle {
-                lower_left: Point2D { x: -0.5, y: -0.5 },
-                upper_right: Point2D { x: 993.5, y: 964.5 },
-            }
-        );
-        assert_eq!(c.position_bits(), end);
-    }
-
-    #[test]
-    fn roundtrip_image_with_poly_clip() {
-        let mut w = BitWriter::new();
-        w.write_bl(0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_rd(100.0);
-        w.write_rd(100.0);
-        w.write_bs(0x01);
-        w.write_b(true);
-        w.write_rc(50);
-        w.write_rc(50);
-        w.write_rc(0);
-        w.write_bs(2); // polygon
-        w.write_bl(3);
-        for (x, y) in [(0.0f64, 0.0), (100.0, 0.0), (50.0, 100.0)] {
-            w.write_rd(x);
-            w.write_rd(y);
-        }
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let i = decode(&mut c, Version::R2000).unwrap();
-        match i.clip_boundary {
-            ClipBoundary::Polygon(pts) => assert_eq!(pts.len(), 3),
-            _ => panic!("expected polygon"),
-        }
-    }
-}
diff --git a/src/entities/imagedef.rs b/src/entities/imagedef.rs
index 3b34162..bf82666 100644
--- a/src/entities/imagedef.rs
+++ b/src/entities/imagedef.rs
@@ -152,83 +152,3 @@ fn read_tv(c: &mut BitCursor<'_>, version: Version) -> Result<String> {
         Ok(crate::code_page::decode_active(&bytes))
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    fn write_tv_8bit(w: &mut BitWriter, s: &str) {
-        w.write_bs_u((s.len() + 1) as u16); // +1 for trailing NUL
-        for b in s.as_bytes() {
-            w.write_rc(*b);
-        }
-        w.write_rc(0);
-    }
-
-    #[test]
-    fn roundtrip_minimal_imagedef() {
-        let mut w = BitWriter::new();
-        w.write_bl(0); // class_version
-        w.write_rd(1920.0);
-        w.write_rd(1080.0);
-        write_tv_8bit(&mut w, "C:\\drawings\\bg.png");
-        w.write_b(true); // is_loaded
-        w.write_rc(1); // mm
-        w.write_rd(0.5);
-        w.write_rd(0.5);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let i = decode(&mut c, Version::R2000).unwrap();
-        assert_eq!(i.class_version, 0);
-        assert_eq!(i.image_size_pixels, (1920.0, 1080.0));
-        assert_eq!(i.file_path, "C:\\drawings\\bg.png");
-        assert!(i.is_loaded);
-        assert_eq!(i.pixel_size_units, 1);
-        assert_eq!(i.pixel_width_size, 0.5);
-        assert_eq!(i.pixel_height_size, 0.5);
-    }
-
-    #[test]
-    fn roundtrip_empty_path() {
-        let mut w = BitWriter::new();
-        w.write_bl(0);
-        w.write_rd(0.0);
-        w.write_rd(0.0);
-        w.write_bs_u(0); // empty TV
-        w.write_b(false);
-        w.write_rc(0); // unitless
-        w.write_rd(1.0);
-        w.write_rd(1.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let i = decode(&mut c, Version::R2000).unwrap();
-        assert_eq!(i.file_path, "");
-        assert!(!i.is_loaded);
-        assert_eq!(i.pixel_size_units, 0);
-    }
-
-    #[test]
-    fn rejects_oversized_tv_claim() {
-        // Claim a path length larger than the cap — must reject before
-        // any RC reads (defensive-allocation).
-        let mut w = BitWriter::new();
-        w.write_bl(0);
-        w.write_rd(0.0);
-        w.write_rd(0.0);
-        // Claim IMAGEDEF_MAX_PATH_UNITS + 1 — beyond the cap.
-        // Because write_bs_u is u16 we can't encode past 65535; use the
-        // cap itself (65536) by writing 0 in the BS_U and... actually
-        // bs_u is limited to u16 so max is 65535. The cap catches
-        // 65536+; use remaining_bits branch for this test instead.
-        //
-        // Drop a large claim (within u16) but with no payload behind
-        // it — remaining_bits will be smaller than the claim.
-        w.write_bs_u(60_000);
-        // no payload
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c, Version::R2000).unwrap_err();
-        assert!(matches!(&err, Error::SectionMap(msg) if msg.contains("IMAGEDEF")));
-    }
-}
diff --git a/src/entities/lofted_surface.rs b/src/entities/lofted_surface.rs
index bb2caa7..ae30583 100644
--- a/src/entities/lofted_surface.rs
+++ b/src/entities/lofted_surface.rs
@@ -83,95 +83,3 @@ pub fn decode(c: &mut BitCursor<'_>) -> Result<LoftedSurface> {
         end_tangent_mag,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::entities::modeler::tests::write_sat_blob;
-
-    #[test]
-    fn roundtrip_loft_three_sections() {
-        let mut w = BitWriter::new();
-        write_sat_blob(
-            &mut w,
-            &SatBlob {
-                empty: false,
-                version: 1,
-                bytes: b"LOFT".to_vec(),
-            },
-        );
-        w.write_bl(3);
-        w.write_handle(2, 0x10);
-        w.write_handle(2, 0x11);
-        w.write_handle(2, 0x12);
-        w.write_bd(1.0);
-        w.write_bd(1.5);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let s = decode(&mut c).unwrap();
-        assert_eq!(s.cross_section_handles.len(), 3);
-        assert_eq!(s.cross_section_handles[0].value, 0x10);
-        assert_eq!(s.cross_section_handles[2].value, 0x12);
-        assert!((s.start_tangent_mag - 1.0).abs() < 1e-12);
-        assert!((s.end_tangent_mag - 1.5).abs() < 1e-12);
-    }
-
-    #[test]
-    fn roundtrip_loft_zero_sections() {
-        // Degenerate but legal: a loft stub with no cross-sections.
-        let mut w = BitWriter::new();
-        write_sat_blob(
-            &mut w,
-            &SatBlob {
-                empty: true,
-                version: 0,
-                bytes: Vec::new(),
-            },
-        );
-        w.write_bl(0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let s = decode(&mut c).unwrap();
-        assert!(s.cross_section_handles.is_empty());
-    }
-
-    #[test]
-    fn rejects_negative_count() {
-        let mut w = BitWriter::new();
-        write_sat_blob(
-            &mut w,
-            &SatBlob {
-                empty: true,
-                version: 0,
-                bytes: Vec::new(),
-            },
-        );
-        w.write_bl(-1);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c).unwrap_err();
-        assert!(matches!(err, Error::SectionMap(_)));
-    }
-
-    #[test]
-    fn rejects_implausible_count() {
-        // Claim more cross-sections than the cap allows.
-        let mut w = BitWriter::new();
-        write_sat_blob(
-            &mut w,
-            &SatBlob {
-                empty: true,
-                version: 0,
-                bytes: Vec::new(),
-            },
-        );
-        w.write_bl(i32::MAX / 2);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c).unwrap_err();
-        assert!(matches!(err, Error::SectionMap(_)));
-    }
-}
diff --git a/src/entities/mesh.rs b/src/entities/mesh.rs
index a4ac590..60fd6ef 100644
--- a/src/entities/mesh.rs
+++ b/src/entities/mesh.rs
@@ -246,190 +246,3 @@ pub fn decode(c: &mut BitCursor<'_>, _version: Version) -> Result<Mesh> {
         creases,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    /// Scalar fields shared by every MESH test fixture. Kept separate
-    /// from the list-valued fields so `write_mesh` stays under the
-    /// 7-arg clippy ceiling without deeply nesting the test payload
-    /// definitions.
-    struct MeshHeader {
-        version: u16,
-        blend_crease: bool,
-        subdivision_level: u16,
-    }
-
-    /// Helper — write a minimal MESH payload for the R2010+ shape.
-    fn write_mesh(
-        w: &mut BitWriter,
-        hdr: &MeshHeader,
-        vertices: &[Point3D],
-        faces: &[&[u32]],
-        edges: &[(u32, u32)],
-        creases: &[f64],
-    ) {
-        w.write_bs_u(hdr.version);
-        w.write_b(hdr.blend_crease);
-        w.write_bs_u(hdr.subdivision_level);
-        w.write_bs_u(vertices.len() as u16);
-        for v in vertices {
-            w.write_bd(v.x);
-            w.write_bd(v.y);
-            w.write_bd(v.z);
-        }
-        // The face list is sized in BL entries: one count per face plus
-        // that face's indices.
-        let face_list_size: usize = faces.iter().map(|f| 1 + f.len()).sum();
-        w.write_bl(face_list_size as i32);
-        for f in faces {
-            w.write_bl(f.len() as i32);
-            for &i in *f {
-                w.write_bl(i as i32);
-            }
-        }
-        w.write_bl(edges.len() as i32);
-        for &(a, b) in edges {
-            w.write_bl_u(a);
-            w.write_bl_u(b);
-        }
-        w.write_bl(creases.len() as i32);
-        for &c in creases {
-            w.write_bd(c);
-        }
-        w.write_bl(0);
-    }
-
-    #[test]
-    fn roundtrip_minimal_cube_cage() {
-        let mut w = BitWriter::new();
-        // A 2-face cage sharing one edge — enough to cover every count
-        // path without drowning the test in coordinates.
-        let verts = [
-            Point3D {
-                x: 0.0,
-                y: 0.0,
-                z: 0.0,
-            },
-            Point3D {
-                x: 1.0,
-                y: 0.0,
-                z: 0.0,
-            },
-            Point3D {
-                x: 1.0,
-                y: 1.0,
-                z: 0.0,
-            },
-            Point3D {
-                x: 0.0,
-                y: 1.0,
-                z: 0.0,
-            },
-        ];
-        let face_a: &[u32] = &[0, 1, 2];
-        let face_b: &[u32] = &[0, 2, 3];
-        let edges = [(0u32, 1u32), (1, 2), (2, 0), (2, 3), (3, 0)];
-        let creases = [0.0f64, 0.0, 1.0, 0.0, 0.0];
-        write_mesh(
-            &mut w,
-            &MeshHeader {
-                version: 0,
-                blend_crease: false,
-                subdivision_level: 2,
-            },
-            &verts,
-            &[face_a, face_b],
-            &edges,
-            &creases,
-        );
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let m = decode(&mut c, Version::R2010).unwrap();
-        assert_eq!(m.version, 0);
-        assert!(!m.blend_crease);
-        assert_eq!(m.subdivision_level, 2);
-        assert_eq!(m.vertices.len(), 4);
-        assert_eq!(
-            m.vertices[1],
-            Point3D {
-                x: 1.0,
-                y: 0.0,
-                z: 0.0
-            }
-        );
-        assert_eq!(m.faces.len(), 2);
-        assert_eq!(m.faces[0], vec![0, 1, 2]);
-        assert_eq!(m.faces[1], vec![0, 2, 3]);
-        assert_eq!(m.edges.len(), 5);
-        assert_eq!(m.edges[2], (2, 0));
-        assert_eq!(m.creases, vec![0.0, 0.0, 1.0, 0.0, 0.0]);
-    }
-
-    #[test]
-    fn roundtrip_blend_crease_true_higher_level() {
-        let mut w = BitWriter::new();
-        let verts = [
-            Point3D {
-                x: 0.0,
-                y: 0.0,
-                z: 0.0,
-            },
-            Point3D {
-                x: 2.0,
-                y: 0.0,
-                z: 0.0,
-            },
-            Point3D {
-                x: 1.0,
-                y: 2.0,
-                z: 0.0,
-            },
-        ];
-        let face: &[u32] = &[0, 1, 2];
-        let edges = [(0u32, 1u32), (1, 2), (2, 0)];
-        let creases = [0.5f64, 0.0, 0.25];
-        write_mesh(
-            &mut w,
-            &MeshHeader {
-                version: 1,
-                blend_crease: true,
-                subdivision_level: 4,
-            },
-            &verts,
-            &[face],
-            &edges,
-            &creases,
-        );
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let m = decode(&mut c, Version::R2013).unwrap();
-        assert_eq!(m.version, 1);
-        assert!(m.blend_crease);
-        assert_eq!(m.subdivision_level, 4);
-        assert_eq!(m.faces[0].len(), 3);
-        assert_eq!(m.creases[0], 0.5);
-        assert_eq!(m.creases[2], 0.25);
-    }
-
-    #[test]
-    fn rejects_oversized_face_list_size() {
-        let mut w = BitWriter::new();
-        // Version + blend + subdivision_level + vertex_count(0)
-        w.write_bs_u(0);
-        w.write_b(false);
-        w.write_bs_u(0);
-        w.write_bs_u(0);
-        // face_list_size far beyond CAP_FACE_LIST
-        w.write_bl(20_000_000);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c, Version::R2010).unwrap_err();
-        assert!(
-            matches!(&err, Error::SectionMap(msg) if msg.contains("face_list_size")),
-            "err={err:?}"
-        );
-    }
-}
diff --git a/src/entities/mleader.rs b/src/entities/mleader.rs
index b4e14da..3b44ca0 100644
--- a/src/entities/mleader.rs
+++ b/src/entities/mleader.rs
@@ -921,247 +921,3 @@ pub fn decode(c: &mut BitCursor<'_>, version: Version) -> Result<MLeader> {
     };
     read_body(c, &mut s, version)
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::string_stream::tests::build_payload;
-
-    /// Append the bits of one BitWriter onto a bit vector.
-    fn bits(w: BitWriter) -> Vec<bool> {
-        crate::string_stream::tests::bits_of(&w)
-    }
-
-    /// Write a `CMC` with no name suffixes.
-    fn write_cmc(w: &mut BitWriter, rgb: u32) {
-        w.write_bs(0);
-        w.write_bl(rgb as i32);
-        w.write_rc(0);
-    }
-
-    /// A minimal but complete R2018 MULTILEADER body: one leader root
-    /// with one two-point leader line, MTEXT content, no columns.
-    fn synth_body() -> Vec<bool> {
-        let mut w = BitWriter::new();
-        w.write_bs(2); // class version (270)
-        // -- context --
-        w.write_bl(1); // one leader root
-        w.write_b(true); // content valid
-        w.write_b(true); // unknown
-        w.write_bd(10.0); // connection point
-        w.write_bd(20.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0); // direction
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bl(0); // no break pairs
-        w.write_bl(0); // leader index
-        w.write_bd(8.0); // landing distance
-        w.write_bl(1); // one leader line
-        w.write_bl(2); // two points
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(5.0);
-        w.write_bd(5.0);
-        w.write_bd(0.0);
-        w.write_bl(0); // no break info
-        w.write_bl(0); // leader line index
-        w.write_bs(1); // leader type = straight
-        write_cmc(&mut w, 0xC100_0000);
-        w.write_bl(-2); // line weight
-        w.write_bd(0.0); // arrow size
-        w.write_bl(0); // override flags
-        w.write_bs(0); // attachment direction (root)
-        w.write_bd(1.0); // overall scale
-        w.write_bd(1.0); // content base point
-        w.write_bd(2.0);
-        w.write_bd(0.0);
-        w.write_bd(4.0); // text height
-        w.write_bd(4.0); // arrow head size
-        w.write_bd(2.0); // landing gap
-        w.write_bs(1); // left attachment
-        w.write_bs(1); // right attachment
-        w.write_bs(0); // text align type
-        w.write_bs(0); // attachment type
-        w.write_b(true); // has text contents
-        // text branch: the TV slot consumes no data bits
-        w.write_bd(0.0); // normal
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(3.0); // location
-        w.write_bd(4.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0); // direction
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0); // rotation
-        w.write_bd(0.0); // boundary width
-        w.write_bd(0.0); // boundary height
-        w.write_bd(1.0); // line spacing factor
-        w.write_bs(1); // line spacing style
-        write_cmc(&mut w, 0xC000_0000); // text colour
-        w.write_bs(1); // alignment
-        w.write_bs(5); // flow direction
-        write_cmc(&mut w, 0xC000_0000); // background colour
-        w.write_bd(0.0); // background scale
-        w.write_bl(0); // background transparency
-        w.write_b(false); // background fill
-        w.write_b(false); // background mask fill
-        w.write_bs(0); // column type
-        w.write_b(false); // text height automatic
-        w.write_bd(0.0); // column width
-        w.write_bd(0.0); // column gutter
-        w.write_b(false); // column flow reversed
-        w.write_bl(0); // no column sizes
-        w.write_b(false); // word break
-        w.write_b(false); // unknown
-        w.write_bd(0.0); // base point
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0); // base direction
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0); // base vertical
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_b(false); // normal reversed
-        w.write_bs(9); // top attachment
-        w.write_bs(9); // bottom attachment
-        // -- style block --
-        w.write_bl(279552); // override flags
-        w.write_bs(1); // leader type
-        write_cmc(&mut w, 0xC100_0000); // leader colour
-        w.write_bl(-2); // line weight
-        w.write_b(true); // landing enabled
-        w.write_b(true); // dogleg enabled
-        w.write_bd(8.0); // landing distance
-        w.write_bd(4.0); // arrow head size
-        w.write_bs(2); // content type = MTEXT
-        w.write_bs(1); // left attachment
-        w.write_bs(1); // right attachment
-        w.write_bs(1); // text angle type
-        w.write_bs(0); // unknown 175
-        write_cmc(&mut w, 0xC100_0000); // text colour
-        w.write_b(false); // text frame enabled
-        write_cmc(&mut w, 0xC100_0000); // block colour
-        w.write_bd(1.0); // block scale
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0); // block rotation
-        w.write_bs(0); // block attachment type
-        w.write_b(false); // is annotative
-        w.write_mc(274).unwrap(); // the undocumented MC
-        w.write_b(true); // the undocumented flag
-        w.write_bs(0); // attachment direction
-        w.write_bs(9); // top attachment
-        w.write_bs(9); // bottom attachment
-        w.write_b(false); // leader extended to text (R2013+)
-        bits(w)
-    }
-
-    /// Round-trip a BitWriter-built R2018 MULTILEADER through the
-    /// split-stream decoder, including the exact-boundary check.
-    #[test]
-    fn roundtrip_minimal_r2018_multileader() {
-        // The record body is the common entity preamble followed by the
-        // MULTILEADER field list; `build_payload` frames it with the
-        // string stream and its trailer.
-        let mut pre = BitWriter::new();
-        pre.write_bs_u(0); // no XDATA
-        pre.write_b(false); // no graphics preview
-        pre.write_bb(0b10); // entmode
-        pre.write_bl(0); // num_reactors
-        pre.write_b(true); // no xdictionary
-        pre.write_b(false); // no AcDs binary data
-        pre.write_bs_u(0x0100); // colour
-        pre.write_bd(1.0); // linetype scale
-        pre.write_bb(0b00); // ltype flags
-        pre.write_bb(0b00); // plotstyle
-        pre.write_bb(0b00); // material
-        pre.write_rc(0); // shadow
-        pre.write_b(false);
-        pre.write_b(false);
-        pre.write_b(false);
-        pre.write_bs(0); // invisibility
-        pre.write_rc(0x1D); // lineweight
-        let mut body = bits(pre);
-        body.extend(synth_body());
-
-        let payload = build_payload(&body, &["MULTILEADER TEST"]);
-        let m = decode_modern_split_stream(&payload, 8, Version::R2018).expect("decodes");
-        assert_eq!(m.class_version, 2);
-        assert_eq!(m.context.leader_roots.len(), 1);
-        let root = &m.context.leader_roots[0];
-        assert_eq!(root.landing_distance, 8.0);
-        assert_eq!(root.lines.len(), 1);
-        assert_eq!(root.lines[0].points.len(), 2);
-        assert_eq!(
-            root.lines[0].points[1],
-            Point3D {
-                x: 5.0,
-                y: 5.0,
-                z: 0.0
-            }
-        );
-        assert_eq!(root.lines[0].line_weight, -2);
-        let text = m.context.text.as_ref().expect("text content");
-        assert_eq!(text.label, "MULTILEADER TEST");
-        assert_eq!(text.flow_direction, 5);
-        assert!(m.context.block.is_none());
-        assert_eq!(m.context.top_attachment, 9);
-        assert_eq!(m.override_flags, 279552);
-        assert_eq!(m.content_type, 2);
-        assert_eq!(
-            m.block_scale,
-            Point3D {
-                x: 1.0,
-                y: 1.0,
-                z: 1.0
-            }
-        );
-        assert!(!m.is_annotative);
-        assert_eq!(m.undocumented_mc, 274);
-        assert!(m.undocumented_flag);
-        assert_eq!(m.bottom_attachment, 9);
-        assert!(!m.leader_extended_to_text);
-    }
-
-    /// A wrong field list must error on the boundary, not return a
-    /// plausible struct: dropping the R2013+ `B 295` leaves the data
-    /// fields one bit short of the string stream.
-    #[test]
-    fn misaligned_field_list_errors() {
-        let mut pre = BitWriter::new();
-        pre.write_bs_u(0);
-        pre.write_b(false);
-        pre.write_bb(0b10);
-        pre.write_bl(0);
-        pre.write_b(true);
-        pre.write_b(false);
-        pre.write_bs_u(0x0100);
-        pre.write_bd(1.0);
-        pre.write_bb(0b00);
-        pre.write_bb(0b00);
-        pre.write_bb(0b00);
-        pre.write_rc(0);
-        pre.write_b(false);
-        pre.write_b(false);
-        pre.write_b(false);
-        pre.write_bs(0);
-        pre.write_rc(0x1D);
-        let mut body = bits(pre);
-        let mut synth = synth_body();
-        synth.pop(); // drop the R2013+ trailing bit
-        body.extend(synth);
-
-        let payload = build_payload(&body, &["MULTILEADER TEST"]);
-        let err = decode_modern_split_stream(&payload, 8, Version::R2018)
-            .expect_err("a short field list must be rejected");
-        assert!(
-            matches!(&err, Error::SectionMap(m) if m.contains("MULTILEADER data fields ended")),
-            "err={err:?}"
-        );
-    }
-}
diff --git a/src/entities/mline.rs b/src/entities/mline.rs
index 3d5e19a..d527975 100644
--- a/src/entities/mline.rs
+++ b/src/entities/mline.rs
@@ -242,134 +242,3 @@ pub fn decode(c: &mut BitCursor<'_>) -> Result<MLine> {
         vertices,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_two_line_three_vertex_mline() {
-        let mut w = BitWriter::new();
-        w.write_bd(1.0); // scale factor
-        w.write_rc(1); // zero justification
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0); // scale_point
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0); // extrusion
-        w.write_bs(0); // open
-        w.write_rc(2); // 2 parallel lines
-        w.write_bs(3); // 3 vertices
-
-        // Vertex 0
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0); // vertex
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0); // seg dir
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0); // miter
-        // Line 0 sub-record: 0 segment params, 0 area-fill params
-        w.write_bs(0);
-        w.write_bs(0);
-        // Line 1 sub-record: same
-        w.write_bs(0);
-        w.write_bs(0);
-
-        // Vertex 1
-        w.write_bd(10.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bs(0);
-        w.write_bs(0);
-        w.write_bs(0);
-        w.write_bs(0);
-
-        // Vertex 2 — with one segment param on line 1 just to exercise
-        // the inner loop.
-        w.write_bd(20.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bs(0);
-        w.write_bs(0); // line 0
-        w.write_bs(1); // line 1: 1 segment param
-        w.write_bd(0.75);
-        w.write_bs(0);
-
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let m = decode(&mut c).unwrap();
-        assert_eq!(m.scale_factor, 1.0);
-        assert_eq!(m.justification, Justification::Zero);
-        assert_eq!(m.num_lines, 2);
-        assert_eq!(m.vertices.len(), 3);
-        assert_eq!(
-            m.vertices[1].vertex_point,
-            Point3D {
-                x: 10.0,
-                y: 0.0,
-                z: 0.0
-            }
-        );
-        // Last vertex, line 1, should have exactly one segment param = 0.75
-        let last = &m.vertices[2].sub_records[1];
-        assert_eq!(last.segment_parameters, vec![0.75]);
-        assert!(last.area_fill_parameters.is_empty());
-    }
-
-    #[test]
-    fn rejects_implausible_vertex_count() {
-        let mut w = BitWriter::new();
-        w.write_bd(1.0);
-        w.write_rc(0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bs(0);
-        w.write_rc(2);
-        // Claim 30000 vertices but no further payload.
-        w.write_bs(30000);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        assert!(decode(&mut c).is_err());
-    }
-
-    #[test]
-    fn unknown_justification_passes_through() {
-        let mut w = BitWriter::new();
-        w.write_bd(1.0);
-        w.write_rc(99); // unknown justification
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bs(0);
-        w.write_rc(0); // 0 lines
-        w.write_bs(0); // 0 vertices
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let m = decode(&mut c).unwrap();
-        assert_eq!(m.justification, Justification::Unknown(99));
-    }
-}
diff --git a/src/entities/modeler.rs b/src/entities/modeler.rs
index 7f32fc4..315c94d 100644
--- a/src/entities/modeler.rs
+++ b/src/entities/modeler.rs
@@ -337,222 +337,3 @@ pub fn decode_record(
         },
     })
 }
-
-#[cfg(test)]
-pub(crate) mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    /// Encode a SAT blob in the same wire shape the underlying
-    /// `three_d_solid` decoder expects. Keeps the per-entity tests
-    /// focused on their own fields without re-stating the chunk loop
-    /// each time.
-    pub(crate) fn write_sat_blob(w: &mut BitWriter, blob: &SatBlob) {
-        if blob.empty {
-            w.write_b(true);
-            return;
-        }
-        w.write_b(false);
-        w.write_b(false); // §20.4.41 unknown bit
-        w.write_bs_u(blob.version);
-        if !blob.bytes.is_empty() {
-            w.write_bl(blob.bytes.len() as i32);
-            for b in &blob.bytes {
-                w.write_rc(*b);
-            }
-        }
-        w.write_bl(0); // terminating block size
-    }
-
-    /// Write the §20.4.41 tail of a record that carries no wireframe
-    /// block and no data-store block.
-    pub(crate) fn write_minimal_tail(w: &mut BitWriter) {
-        w.write_b(false); // wireframe data present
-        w.write_b(true); // ACIS empty (2)
-        w.write_bl(0); // R2007+ unknown
-    }
-
-    #[test]
-    fn roundtrip_empty_blob() {
-        let mut w = BitWriter::new();
-        write_sat_blob(
-            &mut w,
-            &SatBlob {
-                empty: true,
-                version: 0,
-                bytes: Vec::new(),
-            },
-        );
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let b = decode_sat_blob(&mut c).unwrap();
-        assert!(b.empty);
-        assert!(b.bytes.is_empty());
-    }
-
-    #[test]
-    fn roundtrip_one_chunk_blob() {
-        let payload = b"ACIS DUMMY BODY DATA".to_vec();
-        let mut w = BitWriter::new();
-        write_sat_blob(
-            &mut w,
-            &SatBlob {
-                empty: false,
-                version: 1,
-                bytes: payload.clone(),
-            },
-        );
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let b = decode_sat_blob(&mut c).unwrap();
-        assert!(!b.empty);
-        assert_eq!(b.version, 1);
-        assert_eq!(b.bytes, payload);
-    }
-
-    /// The data-store shape measured on `sample_AC1032.dwg`: no inline
-    /// envelope, a wireframe block whose point is real geometry and
-    /// whose isoline count is AutoCAD's default `4`, then the seven
-    /// unknown bits, the revision GUID and the trailing `BL`.
-    #[test]
-    fn roundtrip_r2018_data_store_record() {
-        let guid: [u8; 16] = [
-            0x83, 0x31, 0x11, 0xA1, 0xB7, 0xAC, 0x4D, 0xD4, 0x82, 0x4D, 0x78, 0xB3, 0x36, 0x68,
-            0xF9, 0xE7,
-        ];
-        let mut w = BitWriter::new();
-        w.write_b(true); // wireframe data present
-        w.write_b(true); // point present
-        w.write_bd(17.776_725_469_823_76);
-        w.write_bd(-220.850_122_660_715_93);
-        w.write_bd(2.5);
-        w.write_bl(4); // num isolines
-        w.write_b(true); // isolines present
-        w.write_bl(0); // num wires
-        w.write_bl(0); // num silhouettes
-        w.write_b(true); // ACIS empty (2)
-        w.write_bl(0); // R2007+ unknown
-        w.write_b(true); // unknown_a
-        w.write_bb(0); // unknown_b
-        w.write_bb(0); // unknown_c
-        w.write_bb(0b10); // unknown_d
-        for b in guid {
-            w.write_rc(b);
-        }
-        w.write_bl(0); // unknown_e
-        let end = w.position_bits();
-
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let rec = decode_record(&mut c, Version::R2018, true).unwrap();
-        assert!(rec.in_data_store);
-        assert!(rec.blob.empty);
-        assert!(rec.tail.wireframe_present);
-        assert_eq!(rec.tail.num_isolines, 4);
-        assert!(rec.tail.isolines_present);
-        assert_eq!(rec.tail.num_wires, 0);
-        assert_eq!(rec.tail.num_silhouettes, 0);
-        assert!(rec.tail.acis_empty_2);
-        assert_eq!(rec.tail.revision_guid, Some(guid));
-        let p = rec.tail.point.unwrap();
-        assert_eq!(p.z, 2.5);
-        assert_eq!(c.position_bits(), end);
-    }
-
-    /// A record with an inline envelope and no wireframe block closes
-    /// on the same grammar with the data-store branch off.
-    #[test]
-    fn roundtrip_inline_envelope_record() {
-        let mut w = BitWriter::new();
-        write_sat_blob(
-            &mut w,
-            &SatBlob {
-                empty: false,
-                version: 1,
-                bytes: b"400 0 1 0".to_vec(),
-            },
-        );
-        write_minimal_tail(&mut w);
-        let end = w.position_bits();
-
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let rec = decode_record(&mut c, Version::R2018, false).unwrap();
-        assert!(!rec.blob.empty);
-        assert_eq!(rec.blob.bytes, b"400 0 1 0".to_vec());
-        assert!(!rec.tail.wireframe_present);
-        assert!(rec.tail.acis_empty_2);
-        assert_eq!(rec.tail.revision_guid, None);
-        assert_eq!(c.position_bits(), end);
-    }
-
-    /// A wire list is stepped, not surfaced — but it must still be
-    /// stepped exactly, or the record misses its boundary.
-    #[test]
-    fn wire_and_silhouette_lists_are_stepped_exactly() {
-        let mut w = BitWriter::new();
-        w.write_b(true); // ACIS empty — no inline envelope
-        w.write_b(true); // wireframe data present
-        w.write_b(false); // point present
-        w.write_bl(4);
-        w.write_b(true); // isolines present
-        w.write_bl(1); // one wire
-        w.write_rc(3); // wire type
-        w.write_bl(7); // selection marker
-        w.write_bs(256); // colour
-        w.write_bl(2); // acis index
-        w.write_bl(2); // point count
-        for _ in 0..2 {
-            w.write_bd(1.0);
-            w.write_bd(2.0);
-            w.write_bd(3.0);
-        }
-        w.write_b(true); // transform present
-        for _ in 0..4 {
-            w.write_bd(1.0);
-            w.write_bd(0.0);
-            w.write_bd(0.0);
-        }
-        w.write_bd(1.0); // scale
-        w.write_b(false);
-        w.write_b(false);
-        w.write_b(false);
-        w.write_bl(1); // one silhouette
-        w.write_bl(11); // viewport id
-        for _ in 0..3 {
-            w.write_bd(0.0);
-            w.write_bd(0.0);
-            w.write_bd(1.0);
-        }
-        w.write_b(false); // perspective
-        w.write_bl(0); // silhouette wire count
-        w.write_b(true); // ACIS empty (2)
-        w.write_bl(0); // R2007+ unknown
-        let end = w.position_bits();
-
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let rec = decode_record(&mut c, Version::R2018, false).unwrap();
-        assert_eq!(rec.tail.num_wires, 1);
-        assert_eq!(rec.tail.num_silhouettes, 1);
-        assert_eq!(rec.tail.point, None);
-        assert_eq!(c.position_bits(), end);
-    }
-
-    #[test]
-    fn absurd_wire_count_is_rejected() {
-        let mut w = BitWriter::new();
-        w.write_b(true); // wireframe present
-        w.write_b(false); // point present
-        w.write_bl(4);
-        w.write_b(true); // isolines present
-        w.write_bl(1_000_000); // wire count
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode_record(&mut c, Version::R2018, true).unwrap_err();
-        match err {
-            Error::SectionMap(msg) => assert!(msg.contains("wire count"), "msg: {msg}"),
-            other => panic!("expected SectionMap, got {other:?}"),
-        }
-    }
-}
diff --git a/src/entities/ole2_frame.rs b/src/entities/ole2_frame.rs
index 30dd4d7..379bad9 100644
--- a/src/entities/ole2_frame.rs
+++ b/src/entities/ole2_frame.rs
@@ -80,76 +80,3 @@ pub fn decode(c: &mut BitCursor<'_>) -> Result<Ole2Frame> {
         mode,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_ole2frame_small_blob() {
-        let mut w = BitWriter::new();
-        w.write_bs(2); // ole_version
-        // Four-byte synthetic "blob" — a real OLE 2 header would start
-        // with the Compound Document magic (D0 CF 11 E0 A1 B1 1A E1),
-        // but this test only cares that decode preserves the bytes.
-        let blob = [0xD0u8, 0xCF, 0x11, 0xE0];
-        w.write_bl(blob.len() as i32);
-        for b in blob {
-            w.write_rc(b);
-        }
-        w.write_bs(2); // embedded
-        w.write_rc(0); // mode
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let o = decode(&mut c).unwrap();
-        assert_eq!(o.ole_version, 2);
-        assert_eq!(o.data, blob);
-        assert_eq!(o.oleobject_type, 2);
-        assert_eq!(o.mode, 0);
-    }
-
-    #[test]
-    fn roundtrip_ole2frame_empty_blob() {
-        let mut w = BitWriter::new();
-        w.write_bs(2);
-        w.write_bl(0);
-        w.write_bs(1);
-        w.write_rc(1);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let o = decode(&mut c).unwrap();
-        assert!(o.data.is_empty());
-        assert_eq!(o.oleobject_type, 1);
-        assert_eq!(o.mode, 1);
-    }
-
-    #[test]
-    fn rejects_negative_data_length() {
-        let mut w = BitWriter::new();
-        w.write_bs(2);
-        w.write_bl(-1);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c).unwrap_err();
-        assert!(
-            matches!(&err, Error::SectionMap(msg) if msg.contains("negative data_length")),
-            "err={err:?}"
-        );
-    }
-
-    #[test]
-    fn rejects_excessive_data_length() {
-        let mut w = BitWriter::new();
-        w.write_bs(2);
-        // Claim 32 MiB — exceeds OLE2FRAME_MAX_DATA_BYTES (16 MiB).
-        w.write_bl(32 * 1024 * 1024);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c).unwrap_err();
-        assert!(
-            matches!(&err, Error::SectionMap(msg) if msg.contains("exceeds cap")),
-            "err={err:?}"
-        );
-    }
-}
diff --git a/src/entities/polyface_mesh.rs b/src/entities/polyface_mesh.rs
index 0973316..8f4a578 100644
--- a/src/entities/polyface_mesh.rs
+++ b/src/entities/polyface_mesh.rs
@@ -74,43 +74,3 @@ pub fn decode_record(c: &mut BitCursor<'_>, version: Version) -> Result<Polyface
         num_owned_objects,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    /// The corpus record's own values: 5 vertices, 2 faces, 7 owned
-    /// objects, in exactly 30 bits.
-    #[test]
-    fn roundtrip_measured_r2018_header() {
-        let mut w = BitWriter::new();
-        w.write_bs_u(5);
-        w.write_bs_u(2);
-        w.write_bl(7);
-        assert_eq!(w.position_bits(), 30);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let p = decode_record(&mut c, Version::R2018).unwrap();
-        assert_eq!(p.vertex_count, 5);
-        assert_eq!(p.face_count, 2);
-        assert_eq!(p.num_owned_objects, Some(7));
-        assert_eq!(c.position_bits(), 30);
-    }
-
-    /// Before R2004 the owned-object count is absent, so the same two
-    /// counts close 10 bits earlier.
-    #[test]
-    fn r2000_header_has_no_owned_count() {
-        let mut w = BitWriter::new();
-        w.write_bs_u(8);
-        w.write_bs_u(6);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let p = decode_record(&mut c, Version::R2000).unwrap();
-        assert_eq!(p.vertex_count, 8);
-        assert_eq!(p.face_count, 6);
-        assert_eq!(p.num_owned_objects, None);
-        assert_eq!(c.position_bits(), 20);
-    }
-}
diff --git a/src/entities/polygon_mesh.rs b/src/entities/polygon_mesh.rs
index c663ec3..a5f201c 100644
--- a/src/entities/polygon_mesh.rs
+++ b/src/entities/polygon_mesh.rs
@@ -110,124 +110,3 @@ pub fn decode(c: &mut BitCursor<'_>, version: Version) -> Result<PolygonMesh> {
         num_owned_objects,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    struct PmeshFields {
-        flags: u16,
-        md: u16,
-        nd: u16,
-        m: u16,
-        n: u16,
-    }
-
-    fn write_pmesh(w: &mut BitWriter, f: &PmeshFields) {
-        w.write_bs_u(f.flags);
-        w.write_bs_u(0); // curve type
-        w.write_bs_u(f.m);
-        w.write_bs_u(f.n);
-        w.write_bs_u(f.md);
-        w.write_bs_u(f.nd);
-    }
-
-    #[test]
-    fn roundtrip_open_mesh() {
-        let mut w = BitWriter::new();
-        write_pmesh(
-            &mut w,
-            &PmeshFields {
-                flags: 0,
-                md: 6,
-                nd: 6,
-                m: 5,
-                n: 4,
-            },
-        );
-        let end = w.position_bits();
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let m = decode(&mut c, Version::R2000).unwrap();
-        assert_eq!(m.flags, 0);
-        assert!(!m.is_closed_m());
-        assert!(!m.is_closed_n());
-        assert_eq!(m.m_density, 6);
-        assert_eq!(m.n_density, 6);
-        assert_eq!(m.m_vert_count, 5);
-        assert_eq!(m.n_vert_count, 4);
-        // The six shorts are the whole R2000 data-stream field list — the
-        // vertex-chain handles are not in it.
-        assert_eq!(c.position_bits(), end);
-    }
-
-    #[test]
-    fn roundtrip_cylinder_closed_in_m() {
-        let mut w = BitWriter::new();
-        write_pmesh(
-            &mut w,
-            &PmeshFields {
-                flags: flag_bits::CLOSED_M,
-                md: 8,
-                nd: 4,
-                m: 16,
-                n: 8,
-            },
-        );
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let m = decode(&mut c, Version::R2000).unwrap();
-        assert!(m.is_closed_m());
-        assert!(!m.is_closed_n());
-        assert_eq!(m.m_vert_count, 16);
-        assert_eq!(m.n_vert_count, 8);
-    }
-
-    #[test]
-    fn roundtrip_torus_closed_both() {
-        let mut w = BitWriter::new();
-        write_pmesh(
-            &mut w,
-            &PmeshFields {
-                flags: flag_bits::CLOSED_M | flag_bits::CLOSED_N,
-                md: 8,
-                nd: 8,
-                m: 24,
-                n: 12,
-            },
-        );
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let m = decode(&mut c, Version::R2000).unwrap();
-        assert!(m.is_closed_m());
-        assert!(m.is_closed_n());
-        assert_eq!(m.flags & 0x3, 0x3);
-        assert_eq!(m.m_vert_count, 24);
-        assert_eq!(m.n_vert_count, 12);
-    }
-
-    #[test]
-    fn preserves_unknown_high_flag_bits() {
-        // Files in the wild sometimes carry extra bits we don't
-        // semantically interpret; round-tripping them verbatim is how
-        // the reader stays honest with unknown metadata.
-        let mut w = BitWriter::new();
-        write_pmesh(
-            &mut w,
-            &PmeshFields {
-                flags: 0x8000,
-                md: 2,
-                nd: 3,
-                m: 7,
-                n: 5,
-            },
-        );
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let m = decode(&mut c, Version::R2000).unwrap();
-        assert_eq!(m.flags, 0x8000);
-        assert!(!m.is_closed_m());
-        assert!(!m.is_closed_n());
-    }
-}
diff --git a/src/entities/proxy_entity_passthrough.rs b/src/entities/proxy_entity_passthrough.rs
index 4a8a4a1..2467866 100644
--- a/src/entities/proxy_entity_passthrough.rs
+++ b/src/entities/proxy_entity_passthrough.rs
@@ -104,88 +104,3 @@ pub fn decode(c: &mut BitCursor<'_>, version: Version) -> Result<ProxyEntityPass
         original_object_handle,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_empty_proxy_entity() {
-        let mut w = BitWriter::new();
-        w.write_bl(500); // class id
-        w.write_bl(1); // app version
-        w.write_bl(0); // 0 bits of data
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let p = decode(&mut c, Version::R2000).unwrap();
-        assert_eq!(p.proxy_class_id, 500);
-        assert_eq!(p.application_version, 1);
-        assert_eq!(p.data_size_bits, 0);
-        assert!(p.raw_proxy_data.is_empty());
-        assert!(p.original_object_handle.is_none());
-    }
-
-    #[test]
-    fn roundtrip_proxy_entity_with_payload() {
-        let mut w = BitWriter::new();
-        w.write_bl(501);
-        w.write_bl(2);
-        let payload: [u8; 4] = [0xDE, 0xAD, 0xBE, 0xEF];
-        w.write_bl((payload.len() * 8) as i32);
-        for b in &payload {
-            w.write_rc(*b);
-        }
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let p = decode(&mut c, Version::R2000).unwrap();
-        assert_eq!(p.proxy_class_id, 501);
-        assert_eq!(p.application_version, 2);
-        assert_eq!(p.data_size_bits, 32);
-        assert_eq!(p.raw_proxy_data, &payload);
-    }
-
-    #[test]
-    fn rejects_oversized_data_size_bits() {
-        let mut w = BitWriter::new();
-        w.write_bl(500);
-        w.write_bl(1);
-        // 17 MiB × 8 bits/byte = 142 606 336 — above the cap.
-        w.write_bl(142_606_336);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c, Version::R2000).unwrap_err();
-        assert!(matches!(&err, Error::SectionMap(msg) if msg.contains("PROXY")));
-    }
-
-    #[test]
-    fn rejects_data_size_exceeding_remaining() {
-        let mut w = BitWriter::new();
-        w.write_bl(500);
-        w.write_bl(1);
-        // Claim 1000 bytes of payload but write nothing.
-        w.write_bl(8000);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c, Version::R2000).unwrap_err();
-        assert!(matches!(&err, Error::SectionMap(msg) if msg.contains("remaining_bits")));
-    }
-
-    #[test]
-    fn r2007_attempts_owner_handle_read() {
-        // With padding room for a handle after the payload, R2007 should
-        // opportunistically read one. If the handle is malformed we
-        // fall back to None — but a well-formed one decodes.
-        let mut w = BitWriter::new();
-        w.write_bl(500);
-        w.write_bl(1);
-        w.write_bl(0); // 0 payload bits
-        w.write_handle(5, 0x42);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let p = decode(&mut c, Version::R2007).unwrap();
-        let h = p.original_object_handle.expect("handle should decode");
-        assert_eq!(h.code, 5);
-        assert_eq!(h.value, 0x42);
-    }
-}
diff --git a/src/entities/ray.rs b/src/entities/ray.rs
index e4da3b3..8b4d5e0 100644
--- a/src/entities/ray.rs
+++ b/src/entities/ray.rs
@@ -24,39 +24,3 @@ pub fn decode(c: &mut BitCursor<'_>) -> Result<Ray> {
     let direction = read_bd3(c)?;
     Ok(Ray { start, direction })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_ray() {
-        let mut w = BitWriter::new();
-        w.write_bd(1.0);
-        w.write_bd(2.0);
-        w.write_bd(3.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let r = decode(&mut c).unwrap();
-        assert_eq!(
-            r.start,
-            Point3D {
-                x: 1.0,
-                y: 2.0,
-                z: 3.0
-            }
-        );
-        assert_eq!(
-            r.direction,
-            Vec3D {
-                x: 1.0,
-                y: 0.0,
-                z: 0.0
-            }
-        );
-    }
-}
diff --git a/src/entities/region.rs b/src/entities/region.rs
index 9299062..92cb1b5 100644
--- a/src/entities/region.rs
+++ b/src/entities/region.rs
@@ -67,78 +67,3 @@ pub fn decode_record(
         tail: Some(record.tail),
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_empty_region() {
-        let mut w = BitWriter::new();
-        w.write_b(true); // ACIS empty
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let r = decode(&mut c).unwrap();
-        assert!(r.acis_empty);
-        assert_eq!(r.version, None);
-        assert_eq!(r.sat_blob, None);
-    }
-
-    #[test]
-    fn roundtrip_region_with_blob() {
-        let payload = b"400 0 1 0";
-        let mut w = BitWriter::new();
-        w.write_b(false);
-        w.write_b(false); // §20.4.41 unknown bit
-        w.write_bs_u(1);
-        w.write_bl(payload.len() as i32);
-        for b in payload {
-            w.write_rc(*b);
-        }
-        w.write_bl(0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let r = decode(&mut c).unwrap();
-        assert!(!r.acis_empty);
-        assert_eq!(r.version, Some(1));
-        assert_eq!(r.sat_blob.as_deref(), Some(&payload[..]));
-    }
-
-    /// The R2013+ data-store shape: no inline envelope, a wireframe
-    /// point, `num isolines = 4` and the 16-byte revision GUID.
-    #[test]
-    fn roundtrip_region_data_store_record() {
-        let guid = [0xABu8; 16];
-        let mut w = BitWriter::new();
-        w.write_b(true); // wireframe data present
-        w.write_b(true); // point present
-        w.write_bd(1.0);
-        w.write_bd(2.0);
-        w.write_bd(0.0);
-        w.write_bl(4); // num isolines
-        w.write_b(true); // isolines present
-        w.write_bl(0); // num wires
-        w.write_bl(0); // num silhouettes
-        w.write_b(true); // ACIS empty (2)
-        w.write_bl(0); // R2007+ unknown
-        w.write_b(true);
-        w.write_bb(0);
-        w.write_bb(0);
-        w.write_bb(0b10);
-        for b in guid {
-            w.write_rc(b);
-        }
-        w.write_bl(0);
-        let end = w.position_bits();
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let r = decode_record(&mut c, Version::R2018, true).unwrap();
-        assert!(r.in_data_store);
-        assert!(r.acis_empty);
-        let fields = r.tail.unwrap();
-        assert_eq!(fields.num_isolines, 4);
-        assert_eq!(fields.revision_guid, Some(guid));
-        assert_eq!(c.position_bits(), end);
-    }
-}
diff --git a/src/entities/revolved_surface.rs b/src/entities/revolved_surface.rs
index ed64dbf..f945f44 100644
--- a/src/entities/revolved_surface.rs
+++ b/src/entities/revolved_surface.rs
@@ -47,73 +47,3 @@ pub fn decode(c: &mut BitCursor<'_>) -> Result<RevolvedSurface> {
         sweep_angle,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::entities::modeler::tests::write_sat_blob;
-    use std::f64::consts::PI;
-
-    #[test]
-    fn roundtrip_full_revolution() {
-        let mut w = BitWriter::new();
-        write_sat_blob(
-            &mut w,
-            &SatBlob {
-                empty: false,
-                version: 1,
-                bytes: b"R-SAT".to_vec(),
-            },
-        );
-        // axis origin at (0, 0, 0)
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        // axis direction +Z
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        // 360°
-        w.write_bd(2.0 * PI);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let s = decode(&mut c).unwrap();
-        assert_eq!(s.axis_origin, Point3D::default());
-        assert_eq!(
-            s.axis_direction,
-            Vec3D {
-                x: 0.0,
-                y: 0.0,
-                z: 1.0
-            }
-        );
-        assert!((s.sweep_angle - 2.0 * PI).abs() < 1e-12);
-        assert_eq!(s.sat.version, 1);
-    }
-
-    #[test]
-    fn roundtrip_partial_sweep_with_empty_sat() {
-        let mut w = BitWriter::new();
-        write_sat_blob(
-            &mut w,
-            &SatBlob {
-                empty: true,
-                version: 0,
-                bytes: Vec::new(),
-            },
-        );
-        w.write_bd(5.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bd(PI / 2.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let s = decode(&mut c).unwrap();
-        assert!(s.sat.empty);
-        assert!((s.sweep_angle - PI / 2.0).abs() < 1e-12);
-    }
-}
diff --git a/src/entities/seqend.rs b/src/entities/seqend.rs
index 51ff2a4..0e453ab 100644
--- a/src/entities/seqend.rs
+++ b/src/entities/seqend.rs
@@ -29,16 +29,3 @@ pub struct SeqEnd;
 pub fn decode(_c: &mut BitCursor<'_>) -> Result<SeqEnd> {
     Ok(SeqEnd)
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn seqend_consumes_nothing() {
-        let buf = [0xFFu8; 4];
-        let mut c = BitCursor::new(&buf);
-        let _ = decode(&mut c).unwrap();
-        assert_eq!(c.position_bits(), 0);
-    }
-}
diff --git a/src/entities/spline.rs b/src/entities/spline.rs
index 05830fb..722dd1f 100644
--- a/src/entities/spline.rs
+++ b/src/entities/spline.rs
@@ -250,194 +250,3 @@ fn bounds_check(n: usize, field: &'static str, remaining_bits: usize) -> Result<
         Ok(())
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::string_stream::tests::{bits_of, build_payload};
-
-    fn write_preamble(w: &mut BitWriter) {
-        w.write_bs_u(0);
-        w.write_b(false);
-        w.write_bb(0b10);
-        w.write_bl(0);
-        w.write_b(true);
-        w.write_b(false);
-        w.write_bs_u(0x0100);
-        w.write_bd(1.0);
-        w.write_bb(0b00);
-        w.write_bb(0b00);
-        w.write_bb(0b00);
-        w.write_rc(0);
-        w.write_b(false);
-        w.write_b(false);
-        w.write_b(false);
-        w.write_bs(0);
-        w.write_rc(0x1D);
-    }
-
-    #[test]
-    fn roundtrip_fit_spline_pre_r2013() {
-        let mut w = BitWriter::new();
-        w.write_bl(2); // scenario = fit
-        w.write_bl(3); // degree is a BL
-        w.write_bd(0.01); // fit tolerance
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0); // begin tangent
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0); // end tangent
-        w.write_bl(3); // 3 fit points
-        for (x, y, z) in [(0.0, 0.0, 0.0), (1.0, 1.0, 0.0), (2.0, 0.0, 0.0)] {
-            w.write_bd(x);
-            w.write_bd(y);
-            w.write_bd(z);
-        }
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let s = decode(&mut c, Version::R2000).unwrap();
-        let fit = s.fit.unwrap();
-        assert_eq!(s.degree, 3);
-        assert_eq!(fit.fit_points.len(), 3);
-        assert_eq!(fit.tolerance, 0.01);
-        assert!(s.control.is_none());
-    }
-
-    #[test]
-    fn roundtrip_control_spline_pre_r2013() {
-        let mut w = BitWriter::new();
-        w.write_bl(1); // control-based
-        w.write_bl(3); // degree
-        w.write_b(false); // not rational
-        w.write_b(false); // not closed
-        w.write_b(false); // not periodic
-        w.write_bd(1e-6); // knot tolerance
-        w.write_bd(1e-6); // control tolerance
-        w.write_bl(5); // 5 knots
-        w.write_bl(3); // 3 control points
-        w.write_b(false); // no weights
-        for k in [0.0, 0.0, 0.5, 1.0, 1.0] {
-            w.write_bd(k);
-        }
-        for (x, y, z) in [(0.0, 0.0, 0.0), (1.0, 2.0, 0.0), (2.0, 0.0, 0.0)] {
-            w.write_bd(x);
-            w.write_bd(y);
-            w.write_bd(z);
-        }
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let s = decode(&mut c, Version::R2000).unwrap();
-        let ctl = s.control.unwrap();
-        assert_eq!(ctl.knots.len(), 5);
-        assert_eq!(ctl.control_points.len(), 3);
-        assert!(ctl.weights.is_empty());
-    }
-
-    /// The R2018 shape measured on `sample_AC1032.dwg` handle `0x433`:
-    /// stored scenario `1`, spline flags `0`, knot parameter `15`
-    /// (Custom) — so the control branch is taken — with 8 knots and 4
-    /// control points, and the whole record closing on its
-    /// data-stream boundary.
-    #[test]
-    fn r2018_control_spline_closes_on_the_boundary() {
-        let mut w = BitWriter::new();
-        write_preamble(&mut w);
-        w.write_bl(1); // scenario
-        w.write_bl(0); // spline flags 1
-        w.write_bl(15); // knot parameter = Custom
-        w.write_bl(3); // degree
-        w.write_b(false); // rational
-        w.write_b(false); // closed
-        w.write_b(false); // periodic
-        w.write_bd(1e-9);
-        w.write_bd(1e-10);
-        w.write_bl(8); // num knots
-        w.write_bl(4); // num control points
-        w.write_b(false); // no weights
-        for k in [0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0] {
-            w.write_bd(k);
-        }
-        for i in 0..4u8 {
-            w.write_bd(f64::from(i));
-            w.write_bd(f64::from(i) * 2.0);
-            w.write_bd(0.0);
-        }
-        let body = bits_of(&w);
-        let payload = build_payload(&body, &[]);
-        let s = decode_modern_split_stream(&payload, 8, Version::R2018).unwrap();
-        assert_eq!(s.scenario, 1);
-        assert_eq!(s.knot_param, Some(15));
-        assert_eq!(s.degree, 3);
-        let ctl = s.control.expect("control form");
-        assert_eq!(ctl.knots.len(), 8);
-        assert_eq!(ctl.control_points.len(), 4);
-        assert!(s.fit.is_none());
-    }
-
-    /// The R2018 shape measured on handle `0x434`: the same stored
-    /// scenario `1`, but spline flags `9` (method fit points + use knot
-    /// parameter) and knot parameter `2` (Uniform), which §20.4.40's
-    /// derivation turns into the *fit* branch.
-    #[test]
-    fn r2018_derived_scenario_takes_the_fit_branch() {
-        let mut w = BitWriter::new();
-        write_preamble(&mut w);
-        w.write_bl(1); // stored scenario says control...
-        w.write_bl(9); // ...but the flags say method-fit-points
-        w.write_bl(2); // knot parameter = Uniform (not Custom)
-        w.write_bl(3); // degree
-        w.write_bd(1e-10); // fit tolerance
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0); // begin tangent
-        w.write_bd(0.0);
-        w.write_bd(-1.0);
-        w.write_bd(0.0); // end tangent
-        w.write_bl(2); // 2 fit points
-        for (x, y) in [(250.0, 17.0), (259.0, 27.0)] {
-            w.write_bd(x);
-            w.write_bd(y);
-            w.write_bd(0.0);
-        }
-        let body = bits_of(&w);
-        let payload = build_payload(&body, &[]);
-        let s = decode_modern_split_stream(&payload, 8, Version::R2018).unwrap();
-        assert_eq!(s.scenario, 1);
-        assert_eq!(s.flag1, Some(9));
-        let fit = s.fit.expect("fit form");
-        assert_eq!(fit.fit_points.len(), 2);
-        assert_eq!(fit.tolerance, 1e-10);
-        assert!(s.control.is_none());
-    }
-
-    /// A field list one bit short of the boundary must be rejected,
-    /// not returned.
-    #[test]
-    fn misaligned_field_list_errors() {
-        let mut w = BitWriter::new();
-        write_preamble(&mut w);
-        w.write_bl(1);
-        w.write_bl(0);
-        w.write_bl(15);
-        w.write_bl(3);
-        w.write_b(false);
-        w.write_b(false);
-        w.write_b(false);
-        w.write_bd(1e-9);
-        w.write_bd(1e-10);
-        w.write_bl(0); // num knots
-        w.write_bl(0); // num control points
-        w.write_b(false);
-        let mut body = bits_of(&w);
-        body.push(false); // one bit the field list will not consume
-        let payload = build_payload(&body, &[]);
-        let err = decode_modern_split_stream(&payload, 8, Version::R2018)
-            .expect_err("an extra bit must be rejected");
-        assert!(
-            matches!(&err, Error::SectionMap(m) if m.contains("SPLINE data fields ended")),
-            "err={err:?}"
-        );
-    }
-}
diff --git a/src/entities/swept_surface.rs b/src/entities/swept_surface.rs
index c7a39c4..d5eb4bc 100644
--- a/src/entities/swept_surface.rs
+++ b/src/entities/swept_surface.rs
@@ -91,58 +91,3 @@ pub fn decode(c: &mut BitCursor<'_>) -> Result<SweptSurface> {
         align_option,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::entities::modeler::tests::write_sat_blob;
-
-    #[test]
-    fn roundtrip_swept_surface_with_handle() {
-        let mut w = BitWriter::new();
-        write_sat_blob(
-            &mut w,
-            &SatBlob {
-                empty: false,
-                version: 1,
-                bytes: b"SW".to_vec(),
-            },
-        );
-        // Soft-owner handle (code 2), value 0x42.
-        w.write_handle(2, 0x42);
-        w.write_bb(1); // Normal alignment
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let s = decode(&mut c).unwrap();
-        assert_eq!(s.sat.version, 1);
-        assert_eq!(s.path_handle.code, 2);
-        assert_eq!(s.path_handle.value, 0x42);
-        assert_eq!(s.align_option, AlignOption::Normal);
-    }
-
-    #[test]
-    fn rejects_bad_alignment_enum() {
-        // The BB read at the end of decode() will only ever yield
-        // 0..=3, so the enum converter cannot be driven to an
-        // out-of-range value from decode(). Still, exercise the
-        // converter directly so the error path is covered.
-        assert!(AlignOption::from_bb(4).is_err());
-        assert!(matches!(
-            AlignOption::from_bb(4).unwrap_err(),
-            Error::SectionMap(_)
-        ));
-    }
-
-    #[test]
-    fn align_option_roundtrip() {
-        for opt in [
-            AlignOption::NoAlignment,
-            AlignOption::Normal,
-            AlignOption::Translate,
-            AlignOption::ForcedAlignment,
-        ] {
-            assert_eq!(AlignOption::from_bb(opt.to_bb()).unwrap(), opt);
-        }
-    }
-}
diff --git a/src/entities/three_d_solid.rs b/src/entities/three_d_solid.rs
index 7e7e6d8..c7b2ec6 100644
--- a/src/entities/three_d_solid.rs
+++ b/src/entities/three_d_solid.rs
@@ -262,95 +262,3 @@ fn read_sab_file(c: &mut BitCursor<'_>) -> Result<Vec<u8>> {
         blob.push(c.read_rc()?);
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_empty_body() {
-        // acis_empty = true ⇒ no version, no blocks.
-        let mut w = BitWriter::new();
-        w.write_b(true);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let s = decode(&mut c).unwrap();
-        assert!(s.acis_empty);
-        assert_eq!(s.version, None);
-        assert_eq!(s.sat_blob, None);
-        assert_eq!(s.tail, None);
-    }
-
-    #[test]
-    fn roundtrip_single_block() {
-        // acis_empty=false, unknown, version=1, one 9-byte block, stop.
-        // "400 0 1 0" is the header line every SAT stream opens with.
-        let payload: [u8; 9] = *b"400 0 1 0";
-        let mut w = BitWriter::new();
-        w.write_b(false);
-        w.write_b(false);
-        w.write_bs_u(1);
-        w.write_bl(payload.len() as i32);
-        for b in payload {
-            w.write_rc(b);
-        }
-        w.write_bl(0); // terminating block size
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let s = decode(&mut c).unwrap();
-        assert!(!s.acis_empty);
-        assert_eq!(s.version, Some(1));
-        assert_eq!(s.sat_blob.as_deref(), Some(&payload[..]));
-    }
-
-    #[test]
-    fn roundtrip_multi_block() {
-        // Two blocks that together form "hello, world!".
-        let mut w = BitWriter::new();
-        w.write_b(false);
-        w.write_b(true);
-        w.write_bs_u(1);
-        w.write_bl(7);
-        for b in b"hello, " {
-            w.write_rc(*b);
-        }
-        w.write_bl(6);
-        for b in b"world!" {
-            w.write_rc(*b);
-        }
-        w.write_bl(0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let s = decode(&mut c).unwrap();
-        assert_eq!(s.version, Some(1));
-        assert_eq!(s.sat_blob.as_deref(), Some(&b"hello, world!"[..]));
-    }
-
-    #[test]
-    fn block_size_over_remaining_rejected() {
-        // Claim 1_000_000 bytes in a single block but provide almost
-        // nothing. Must return SectionMap, not allocate 1M.
-        let mut w = BitWriter::new();
-        w.write_b(false);
-        w.write_b(false);
-        w.write_bs_u(1);
-        w.write_bl(1_000_000);
-        // No payload follows — cursor runs out.
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c).unwrap_err();
-        match err {
-            Error::SectionMap(msg) => {
-                assert!(msg.contains("exceeds remaining cursor"), "msg: {msg}");
-            }
-            other => panic!("expected SectionMap, got {other:?}"),
-        }
-    }
-
-    #[test]
-    fn max_sat_blob_cap_constant() {
-        // Compile-time sanity: 32 MiB.
-        assert_eq!(MAX_SAT_BLOB_BYTES, 32 * 1024 * 1024);
-    }
-}
diff --git a/src/entities/underlay.rs b/src/entities/underlay.rs
index 90bb689..0b6080f 100644
--- a/src/entities/underlay.rs
+++ b/src/entities/underlay.rs
@@ -156,114 +156,3 @@ pub fn decode(c: &mut BitCursor<'_>, kind: UnderlayKind) -> Result<Underlay> {
         clip_polygon,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    fn write_minimal_underlay(flags: u8, clip_verts: &[(f64, f64)]) -> Vec<u8> {
-        let mut w = BitWriter::new();
-        // normal
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        // insertion_point
-        w.write_bd(1.0);
-        w.write_bd(2.0);
-        w.write_bd(0.0);
-        // rotation
-        w.write_bd(0.0);
-        // scale
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        // flags / contrast / fade
-        w.write_rc(flags);
-        w.write_rc(75);
-        w.write_rc(20);
-        // clip polygon
-        w.write_bs(clip_verts.len() as i16);
-        for (x, y) in clip_verts {
-            w.write_bd(*x);
-            w.write_bd(*y);
-        }
-        w.into_bytes()
-    }
-
-    #[test]
-    fn roundtrip_pdf_underlay_with_rect_clip() {
-        let bytes = write_minimal_underlay(0x03, &[(0.0, 0.0), (10.0, 10.0)]);
-        let mut c = BitCursor::new(&bytes);
-        let u = decode(&mut c, UnderlayKind::Pdf).unwrap();
-        assert_eq!(u.kind, UnderlayKind::Pdf);
-        assert_eq!(
-            u.insertion_point,
-            Point3D {
-                x: 1.0,
-                y: 2.0,
-                z: 0.0
-            }
-        );
-        assert_eq!(u.contrast, 75);
-        assert_eq!(u.fade, 20);
-        assert_eq!(u.clip_polygon.len(), 2);
-        assert!(u.is_clip_on());
-        assert!(u.is_underlay_on());
-        assert!(!u.is_monochrome());
-        assert!(!u.is_adjust_for_background());
-    }
-
-    #[test]
-    fn roundtrip_dwf_underlay_no_clip() {
-        let bytes = write_minimal_underlay(0x02, &[]);
-        let mut c = BitCursor::new(&bytes);
-        let u = decode(&mut c, UnderlayKind::Dwf).unwrap();
-        assert_eq!(u.kind, UnderlayKind::Dwf);
-        assert!(u.clip_polygon.is_empty());
-        assert!(!u.is_clip_on());
-        assert!(u.is_underlay_on());
-    }
-
-    #[test]
-    fn roundtrip_dgn_underlay_preserves_flags() {
-        let bytes = write_minimal_underlay(0x0F, &[(0.0, 0.0)]);
-        let mut c = BitCursor::new(&bytes);
-        let u = decode(&mut c, UnderlayKind::Dgn).unwrap();
-        assert_eq!(u.kind, UnderlayKind::Dgn);
-        assert_eq!(u.flags, 0x0F);
-        assert!(u.is_monochrome());
-        assert!(u.is_adjust_for_background());
-    }
-
-    #[test]
-    fn rejects_excessive_clip_verts() {
-        // Write a payload that *claims* far more verts than fit, via a
-        // BS that encodes a large positive value. We stop after the BS
-        // since decode should reject before reading the polygon.
-        let mut w = BitWriter::new();
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_bd(1.0);
-        w.write_rc(0);
-        w.write_rc(0);
-        w.write_rc(0);
-        // A BS that reads as 32767 (max i16). 32767 BD2s need ~16 million
-        // bits of payload but only a handful remain.
-        w.write_bs(32767);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let err = decode(&mut c, UnderlayKind::Pdf).unwrap_err();
-        assert!(
-            matches!(&err, Error::SectionMap(msg) if msg.contains("UNDERLAY clip verts")),
-            "err={err:?}"
-        );
-    }
-}
diff --git a/src/entities/vertex.rs b/src/entities/vertex.rs
index c62c136..05146c3 100644
--- a/src/entities/vertex.rs
+++ b/src/entities/vertex.rs
@@ -154,91 +154,3 @@ pub fn decode_pface_face(c: &mut BitCursor<'_>) -> Result<VertexPfaceFace> {
     }
     Ok(VertexPfaceFace { vertex_indices })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    /// The measured VERTEX_3D shape: flag `0x20` then a point whose z
-    /// defaults, in exactly 142 bits.
-    #[test]
-    fn roundtrip_measured_vertex_3d() {
-        let mut w = BitWriter::new();
-        w.write_rc(0x20);
-        w.write_bd(232.60172074430375);
-        w.write_bd(0.8926935903469939);
-        w.write_bd(0.0);
-        assert_eq!(w.position_bits(), 142);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let v = decode_point(&mut c).unwrap();
-        assert_eq!(v.flag, 0x20);
-        assert_eq!(v.location.z, 0.0);
-        assert_eq!(c.position_bits(), 142);
-    }
-
-    /// The measured VERTEX_PFACE_FACE shape: four `BS`, one negative
-    /// (invisible edge), in exactly 48 bits.
-    #[test]
-    fn roundtrip_measured_pface_face() {
-        let mut w = BitWriter::new();
-        for value in [1i16, 2, 3, -4] {
-            w.write_bs(value);
-        }
-        assert_eq!(w.position_bits(), 48);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let f = decode_pface_face(&mut c).unwrap();
-        assert_eq!(f.vertex_indices, [1, 2, 3, -4]);
-        assert_eq!(c.position_bits(), 48);
-    }
-
-    #[test]
-    fn roundtrip_simple_vertex_r2000() {
-        let mut w = BitWriter::new();
-        w.write_rc(0x00); // no flags
-        w.write_bd(1.0);
-        w.write_bd(2.0);
-        w.write_bd(3.0);
-        w.write_bd(0.0); // start width
-        w.write_bd(0.0); // end width
-        w.write_bd(0.0); // bulge
-        w.write_bd(0.0); // tangent dir: §20.4.11 stores it on every vertex
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let v = decode(&mut c, Version::R2000).unwrap();
-        assert_eq!(
-            v.location,
-            Point3D {
-                x: 1.0,
-                y: 2.0,
-                z: 3.0
-            }
-        );
-        assert!(v.vertex_id.is_none());
-        assert_eq!(v.tangent_direction, Some(0.0));
-    }
-
-    #[test]
-    fn roundtrip_vertex_with_tangent_r2018() {
-        let mut w = BitWriter::new();
-        w.write_rc(0x02); // tangent present
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0); // start width
-        w.write_bd(2.0); // end width
-        w.write_bd(0.5); // bulge
-        w.write_bl(42); // vertex id
-        w.write_bd(std::f64::consts::FRAC_PI_4); // tangent
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let v = decode(&mut c, Version::R2018).unwrap();
-        assert_eq!(v.vertex_id, Some(42));
-        assert!((v.tangent_direction.unwrap() - std::f64::consts::FRAC_PI_4).abs() < 1e-12);
-        assert_eq!(v.bulge, 0.5);
-        assert_eq!(v.start_width, 1.0);
-        assert_eq!(v.end_width, 2.0);
-    }
-}
diff --git a/src/entities/wipeout.rs b/src/entities/wipeout.rs
index 6d2abef..8512b8e 100644
--- a/src/entities/wipeout.rs
+++ b/src/entities/wipeout.rs
@@ -42,55 +42,3 @@ pub type Wipeout = super::image::Image;
 pub fn decode(c: &mut BitCursor<'_>, version: Version) -> Result<Wipeout> {
     super::image::decode(c, version)
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-    use crate::entities::image::ClipBoundary;
-
-    /// The measured `sample_AC1032.dwg` WIPEOUT body: a polygon clip
-    /// with an explicit vertex count, decoded through the IMAGE layout.
-    #[test]
-    fn decodes_the_measured_polygon_wipeout_body() {
-        let mut w = BitWriter::new();
-        w.write_bl(0); // class_version
-        w.write_bd(271.9211288808192); // insertion point
-        w.write_bd(3.988123351850959);
-        w.write_bd(0.0);
-        w.write_bd(31.707742926072683); // u vector
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0); // v vector
-        w.write_bd(31.707742926072683);
-        w.write_bd(0.0);
-        w.write_rd(1.0); // image size
-        w.write_rd(1.0);
-        w.write_bs(7); // display flags
-        w.write_b(true); // clipping
-        w.write_rc(50); // brightness
-        w.write_rc(50); // contrast
-        w.write_rc(0); // fade
-        w.write_b(false); // clip mode (R2010+)
-        w.write_bs(2); // polygon boundary
-        w.write_bl(4); // vertex count
-        for (x, y) in [(0.0f64, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0)] {
-            w.write_rd(x);
-            w.write_rd(y);
-        }
-        let end = w.position_bits();
-
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let wp = decode(&mut c, Version::R2018).unwrap();
-        assert_eq!(wp.brightness, 50);
-        assert_eq!(wp.contrast, 50);
-        assert_eq!(wp.fade, 0);
-        assert!(wp.clipping);
-        match &wp.clip_boundary {
-            ClipBoundary::Polygon(pts) => assert_eq!(pts.len(), 4),
-            other => panic!("expected a polygon boundary, got {other:?}"),
-        }
-        assert_eq!(c.position_bits(), end);
-    }
-}
diff --git a/src/entities/xline.rs b/src/entities/xline.rs
index 61fc4fb..a2c3c8c 100644
--- a/src/entities/xline.rs
+++ b/src/entities/xline.rs
@@ -20,25 +20,3 @@ pub fn decode(c: &mut BitCursor<'_>) -> Result<XLine> {
     let direction = read_bd3(c)?;
     Ok(XLine { point, direction })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::bitwriter::BitWriter;
-
-    #[test]
-    fn roundtrip_xline() {
-        let mut w = BitWriter::new();
-        w.write_bd(5.0);
-        w.write_bd(5.0);
-        w.write_bd(0.0);
-        w.write_bd(0.0);
-        w.write_bd(1.0);
-        w.write_bd(0.0);
-        let bytes = w.into_bytes();
-        let mut c = BitCursor::new(&bytes);
-        let x = decode(&mut c).unwrap();
-        assert_eq!(x.point.x, 5.0);
-        assert_eq!(x.direction.y, 1.0);
-    }
-}