diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4ec7a1fc..2ca9eb7e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -44,74 +44,27 @@ jobs:
           unzip -q /tmp/godot.zip -d ~/godot
           mv ~/godot/Godot_v${GODOT_VERSION}_linux.x86_64 ~/godot/godot
 
-      - name: Import project
-        run: ~/godot/godot --headless --path "$PROJECT" --import
+      - name: Cache imported resources
+        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
+        with:
+          path: ${{ env.PROJECT }}/.godot
+          key: godot-import-${{ env.GODOT_VERSION }}-${{ hashFiles('hoppys-adventure-arcade/project.godot', 'hoppys-adventure-arcade/**/*.import') }}
+          # A stale cache is safe: Godot reimports any source whose hash changed.
+          restore-keys: godot-import-${{ env.GODOT_VERSION }}-
 
-      # Headless suites only. Not listed here:
-      # - capture_runner_menu_previews, perf_probe, runner_perf_probe, runner_pickup_hitch
-      #   need a real window/GPU and are run locally (see CONTRIBUTING.md).
-      # - menu_smoke and menu_hoppy_smoke rely on pointer hover, which doesn't happen headless
-      #   (2 failures each, also on main).
-      - name: Run headless suites
-        run: |
-          suites=(
-            code_city_assets
-            code_city_celebration
-            code_city_logic
-            code_city_mini_boss
-            code_city_motion
-            code_city_smoke
-            controller_service
-            stage_flow
-            beatemup_knockout
-            beatemup_story
-            beatemup_minimap
-            heroes_villains_assets
-            heroes_villains_logic
-            heroes_villains_motion
-            heroes_villains_smoke
-            hoppy_armed_assets
-            enchanted_assets
-            enchanted_boundaries
-            enchanted_repo_smoke
-            menu_return_layout
-            orbital_assets
-            orbital_ops_smoke
-            platformer_boss
-            platformer_knockout
-            platformer_smoke
-            platformer_traversal
-            runner_boss_validator
-            runner_chunk_validator
-            runner_logic
-            runner_run_intro
-            runner_run_intro_ui
-            runner_scaffold_check
-            runner_smoke
-            runner_synth_threads
-            runner_visual_smoke
-            runner_warmup_check
-          )
-          failed=()
-          for suite in "${suites[@]}"; do
-            echo "::group::$suite"
-            log="/tmp/$suite.log"
-            set +e
-            timeout 600 ~/godot/godot --headless --path "$PROJECT" \
-              --script "res://tests/$suite.gd" 2>&1 | tee "$log"
-            rc=${PIPESTATUS[0]}
-            set -e
-            echo "::endgroup::"
-            # A script that fails to parse can still exit 0, so treat SCRIPT ERROR as a failure too.
-            if [ "$rc" -ne 0 ] || grep -q "SCRIPT ERROR" "$log"; then
-              echo "::error title=$suite::failed (exit $rc)"
-              failed+=("$suite")
-            fi
-          done
-          if [ ${#failed[@]} -gt 0 ]; then
-            echo "Failed suites: ${failed[*]}"
-            exit 1
-          fi
+      # The runner imports first (failing on any engine error), then runs every tests/**/*.gd;
+      # tools/tests/suites.toml lists the few skipped or serial suites and why.
+      - name: Import and run headless suites
+        run: python3 tools/tests/run_tests.py --godot ~/godot/godot --jobs 4
+
+      - name: Upload test results
+        if: always()
+        uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
+        with:
+          name: test-results
+          path: build/test-results/
+          retention-days: 7
+          if-no-files-found: ignore
 
       # Quits from the hub, fights, the Code City celebration, the runner intro and mid-transition
       # with their audio playing. Godot prints its exit-leak lines only after the script is gone,
@@ -133,6 +86,8 @@ jobs:
       - run: pip install ruff gdtoolkit==4.*
       - name: Ruff (tools)
         run: ruff check tools hoppys-adventure-arcade/tools
+      - name: Test runner unit tests
+        run: python -m unittest discover -s tools/tests -v
       # Advisory until the existing code is formatted; make it blocking afterwards.
       - name: gdlint (advisory)
         continue-on-error: true
diff --git a/.gitignore b/.gitignore
index 184628f8..ee942587 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,5 +24,5 @@ __pycache__/
 .vscode/
 .DS_Store
 
-# Exported game builds (tools/build/export_game.py)
+# Build outputs: exported games (tools/build) and test results (tools/tests)
 /build/
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 41f3a684..101b8f3d 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -29,14 +29,26 @@ Thanks for helping out! This guide covers setup, workflow, testing and the asset
 
 ## Tests
 
-The tests are standalone `SceneTree` scripts. Each one exits nonzero on failure:
+The tests are standalone `SceneTree` scripts under `hoppys-adventure-arcade/tests/`. Run them all the way CI does:
+
+```sh
+python3 tools/tests/run_tests.py --godot /path/to/Godot      # or set $GODOT
+python3 tools/tests/run_tests.py -k runner                   # suites whose name contains "runner"
+python3 tools/tests/run_tests.py --list                      # what runs and what is skipped
+```
+
+- **Every new `.gd` file under `tests/` that `extends SceneTree` or `MainLoop` runs automatically.** Shared helpers that extend anything else, such as `tests/support/`, are never run as suites. There's no list to update. To keep a suite out of CI (it needs a GPU, a window or pointer hover), add it to `[skip]` in [`tools/tests/suites.toml`](tools/tests/suites.toml) with the reason.
+- **A suite fails if it exits nonzero, times out, or prints an engine or script error or an exit-time leak.** Suites run with `--verbose`, so a leak names the objects involved. The one tolerated shape is the engine's audio-teardown race: only `AudioStream*` playbacks and audio files, reported as a note. Anything else that leaks fails. That includes `ERROR:`, `SCRIPT ERROR`, parse errors and "leaked at exit". If a test provokes an engine error on purpose, list a pattern for it under `[expected_errors]`; the runner fails if that pattern stops matching.
+- **Finish a suite with `await root.get_node("AudioService").settle()` before `quit()`.** It stops the shared music and waits until the audio thread has released it. A fixed delay is not enough under parallel load.
+- Each suite gets a private user-data root (`HOME`, the XDG directories, and `APPDATA` on Windows), so `user://` files (settings, leaderboards) never touch your real ones. The runner checks this with Godot before starting and refuses to run if `user://` would escape. Suites listed under `[serial]` (wall-clock budgets, or suites that occupy every core) run alone after the parallel batch. Results are written to `build/test-results/summary.json`.
+
+To run a single suite directly:
 
 ```sh
 godot --headless --path hoppys-adventure-arcade --script res://tests/runner_logic.gd
-godot --headless --path hoppys-adventure-arcade --script res://tests/platformer_smoke.gd
 ```
 
-CI runs every headless suite listed in `.github/workflows/ci.yml`. It also runs `python3 tools/checks/exit_leak.py --godot <godot>`, which quits from screens with audio playing and fails on Godot's "leaked at exit" lines. Add a focused regression test when you change behavior. Some suites capture screenshots when run without `--headless`; include those in the PR for visual changes. On macOS, pass `--always-on-top` for graphical runs so the capture doesn't stall when the window is covered.
+CI also runs `python3 tools/checks/exit_leak.py --godot <godot>`, which quits from screens with audio playing and fails on Godot's "leaked at exit" lines. Add a focused regression test when you change behavior. Some suites capture screenshots when run without `--headless`; include those in the PR for visual changes. On macOS, pass `--always-on-top` for graphical runs so the capture doesn't stall when the window is covered.
 
 Per-mode notes and test details live in [`docs/`](docs/).
 
diff --git a/README.md b/README.md
index 43997e78..bf0bff7f 100644
--- a/README.md
+++ b/README.md
@@ -43,11 +43,10 @@ Versioned macOS, Windows, Linux and Web builds come from the [Build workflow](.g
 ## Tests
 
 ```sh
-godot --headless --path hoppys-adventure-arcade --import
-godot --headless --path hoppys-adventure-arcade --script res://tests/runner_logic.gd
+python3 tools/tests/run_tests.py --godot /path/to/Godot
 ```
 
-Each file in `hoppys-adventure-arcade/tests/` is a standalone script that exits nonzero on failure. CI runs the headless suites on every PR. See [CONTRIBUTING.md](CONTRIBUTING.md) for the full workflow.
+CI discovers the suites in `hoppys-adventure-arcade/tests/`: every script that extends `SceneTree` or `MainLoop`. Helpers such as `tests/support/` are not suites. It runs all of them on every PR, except the few listed with a reason in [`tools/tests/suites.toml`](tools/tests/suites.toml). A suite fails on a nonzero exit, an engine or script error, or a leak. See [CONTRIBUTING.md](CONTRIBUTING.md#tests) for details.
 
 ## Contributing
 
diff --git a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_albedo.png.import b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_albedo.png.import
index 4556aa30..e5135bce 100644
--- a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_albedo.png.import
+++ b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_albedo.png.import
@@ -3,10 +3,9 @@
 importer="texture"
 type="CompressedTexture2D"
 uid="uid://0smaw6gfvyj5"
-path.s3tc="res://.godot/imported/hoppy_accessory_albedo.png-c122b57ea96ce5ad67ded19ac527ca90.s3tc.ctex"
+path="res://.godot/imported/hoppy_accessory_albedo.png-c122b57ea96ce5ad67ded19ac527ca90.ctex"
 metadata={
-"imported_formats": ["s3tc_bptc"],
-"vram_texture": true
+"vram_texture": false
 }
 generator_parameters={
 "md5": "12ea3843bd9e25b4241e0d5e33b33f0e"
@@ -15,11 +14,11 @@ generator_parameters={
 [deps]
 
 source_file="res://Assets/runner/hoppy/hoppy_accessory_albedo.png"
-dest_files=["res://.godot/imported/hoppy_accessory_albedo.png-c122b57ea96ce5ad67ded19ac527ca90.s3tc.ctex"]
+dest_files=["res://.godot/imported/hoppy_accessory_albedo.png-c122b57ea96ce5ad67ded19ac527ca90.ctex"]
 
 [params]
 
-compress/mode=2
+compress/mode=0
 compress/high_quality=false
 compress/lossy_quality=0.7
 compress/uastc_level=0
diff --git a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_emissive.png.import b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_emissive.png.import
index 99c24327..11527a38 100644
--- a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_emissive.png.import
+++ b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_emissive.png.import
@@ -3,10 +3,9 @@
 importer="texture"
 type="CompressedTexture2D"
 uid="uid://dk6fxo7twe0us"
-path.s3tc="res://.godot/imported/hoppy_accessory_emissive.png-12050a52c862b1593e1bc121f8f122fa.s3tc.ctex"
+path="res://.godot/imported/hoppy_accessory_emissive.png-12050a52c862b1593e1bc121f8f122fa.ctex"
 metadata={
-"imported_formats": ["s3tc_bptc"],
-"vram_texture": true
+"vram_texture": false
 }
 generator_parameters={
 "md5": "ee72f210ceb66159b7d3d224a51ebf7a"
@@ -15,11 +14,11 @@ generator_parameters={
 [deps]
 
 source_file="res://Assets/runner/hoppy/hoppy_accessory_emissive.png"
-dest_files=["res://.godot/imported/hoppy_accessory_emissive.png-12050a52c862b1593e1bc121f8f122fa.s3tc.ctex"]
+dest_files=["res://.godot/imported/hoppy_accessory_emissive.png-12050a52c862b1593e1bc121f8f122fa.ctex"]
 
 [params]
 
-compress/mode=2
+compress/mode=0
 compress/high_quality=false
 compress/lossy_quality=0.7
 compress/uastc_level=0
diff --git a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_normal.png.import b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_normal.png.import
index 743e2ae2..ed693784 100644
--- a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_normal.png.import
+++ b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_normal.png.import
@@ -3,10 +3,9 @@
 importer="texture"
 type="CompressedTexture2D"
 uid="uid://b27dm5dn5qhlj"
-path.s3tc="res://.godot/imported/hoppy_accessory_normal.png-8498ac34154d1c36039fcb9428c418ee.s3tc.ctex"
+path="res://.godot/imported/hoppy_accessory_normal.png-8498ac34154d1c36039fcb9428c418ee.ctex"
 metadata={
-"imported_formats": ["s3tc_bptc"],
-"vram_texture": true
+"vram_texture": false
 }
 generator_parameters={
 "md5": "ca837196a548101c4ce1d30a9644f167"
@@ -15,11 +14,11 @@ generator_parameters={
 [deps]
 
 source_file="res://Assets/runner/hoppy/hoppy_accessory_normal.png"
-dest_files=["res://.godot/imported/hoppy_accessory_normal.png-8498ac34154d1c36039fcb9428c418ee.s3tc.ctex"]
+dest_files=["res://.godot/imported/hoppy_accessory_normal.png-8498ac34154d1c36039fcb9428c418ee.ctex"]
 
 [params]
 
-compress/mode=2
+compress/mode=0
 compress/high_quality=false
 compress/lossy_quality=0.7
 compress/uastc_level=0
diff --git a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_orm.png.import b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_orm.png.import
index 7838bf8b..9186cc7a 100644
--- a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_orm.png.import
+++ b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_accessory_orm.png.import
@@ -3,10 +3,9 @@
 importer="texture"
 type="CompressedTexture2D"
 uid="uid://bq52lv7petqa7"
-path.s3tc="res://.godot/imported/hoppy_accessory_orm.png-a24d2bbfa7539917534e8ce2748bee64.s3tc.ctex"
+path="res://.godot/imported/hoppy_accessory_orm.png-a24d2bbfa7539917534e8ce2748bee64.ctex"
 metadata={
-"imported_formats": ["s3tc_bptc"],
-"vram_texture": true
+"vram_texture": false
 }
 generator_parameters={
 "md5": "16227a4c91bb686a5186ac40be1c526f"
@@ -15,11 +14,11 @@ generator_parameters={
 [deps]
 
 source_file="res://Assets/runner/hoppy/hoppy_accessory_orm.png"
-dest_files=["res://.godot/imported/hoppy_accessory_orm.png-a24d2bbfa7539917534e8ce2748bee64.s3tc.ctex"]
+dest_files=["res://.godot/imported/hoppy_accessory_orm.png-a24d2bbfa7539917534e8ce2748bee64.ctex"]
 
 [params]
 
-compress/mode=2
+compress/mode=0
 compress/high_quality=false
 compress/lossy_quality=0.7
 compress/uastc_level=0
diff --git a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_albedo.png.import b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_albedo.png.import
index e3441b66..ab0a8960 100644
--- a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_albedo.png.import
+++ b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_albedo.png.import
@@ -3,10 +3,9 @@
 importer="texture"
 type="CompressedTexture2D"
 uid="uid://dk1u3h8nede88"
-path.s3tc="res://.godot/imported/hoppy_body_albedo.png-a4c37408013e37c8de18072982be504d.s3tc.ctex"
+path="res://.godot/imported/hoppy_body_albedo.png-a4c37408013e37c8de18072982be504d.ctex"
 metadata={
-"imported_formats": ["s3tc_bptc"],
-"vram_texture": true
+"vram_texture": false
 }
 generator_parameters={
 "md5": "8d1ce8c41029007e13f41ee644bd020e"
@@ -15,11 +14,11 @@ generator_parameters={
 [deps]
 
 source_file="res://Assets/runner/hoppy/hoppy_body_albedo.png"
-dest_files=["res://.godot/imported/hoppy_body_albedo.png-a4c37408013e37c8de18072982be504d.s3tc.ctex"]
+dest_files=["res://.godot/imported/hoppy_body_albedo.png-a4c37408013e37c8de18072982be504d.ctex"]
 
 [params]
 
-compress/mode=2
+compress/mode=0
 compress/high_quality=false
 compress/lossy_quality=0.7
 compress/uastc_level=0
diff --git a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_emissive.png.import b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_emissive.png.import
index af6f5bcc..681166a6 100644
--- a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_emissive.png.import
+++ b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_emissive.png.import
@@ -3,10 +3,9 @@
 importer="texture"
 type="CompressedTexture2D"
 uid="uid://cnwbddowongvs"
-path.s3tc="res://.godot/imported/hoppy_body_emissive.png-15b9193f78dd32e62b3bc8d4f2eb5591.s3tc.ctex"
+path="res://.godot/imported/hoppy_body_emissive.png-15b9193f78dd32e62b3bc8d4f2eb5591.ctex"
 metadata={
-"imported_formats": ["s3tc_bptc"],
-"vram_texture": true
+"vram_texture": false
 }
 generator_parameters={
 "md5": "efeebdda98ec1d7fb2ad83d23f0713bf"
@@ -15,11 +14,11 @@ generator_parameters={
 [deps]
 
 source_file="res://Assets/runner/hoppy/hoppy_body_emissive.png"
-dest_files=["res://.godot/imported/hoppy_body_emissive.png-15b9193f78dd32e62b3bc8d4f2eb5591.s3tc.ctex"]
+dest_files=["res://.godot/imported/hoppy_body_emissive.png-15b9193f78dd32e62b3bc8d4f2eb5591.ctex"]
 
 [params]
 
-compress/mode=2
+compress/mode=0
 compress/high_quality=false
 compress/lossy_quality=0.7
 compress/uastc_level=0
diff --git a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_normal.png.import b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_normal.png.import
index e609bffd..2bf62b1c 100644
--- a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_normal.png.import
+++ b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_normal.png.import
@@ -3,10 +3,9 @@
 importer="texture"
 type="CompressedTexture2D"
 uid="uid://d2rcbm37d6nu4"
-path.s3tc="res://.godot/imported/hoppy_body_normal.png-904e19f0aa8db2d232ac2f9e1ac495c8.s3tc.ctex"
+path="res://.godot/imported/hoppy_body_normal.png-904e19f0aa8db2d232ac2f9e1ac495c8.ctex"
 metadata={
-"imported_formats": ["s3tc_bptc"],
-"vram_texture": true
+"vram_texture": false
 }
 generator_parameters={
 "md5": "d338760e3eb0d148b22941e704792983"
@@ -15,11 +14,11 @@ generator_parameters={
 [deps]
 
 source_file="res://Assets/runner/hoppy/hoppy_body_normal.png"
-dest_files=["res://.godot/imported/hoppy_body_normal.png-904e19f0aa8db2d232ac2f9e1ac495c8.s3tc.ctex"]
+dest_files=["res://.godot/imported/hoppy_body_normal.png-904e19f0aa8db2d232ac2f9e1ac495c8.ctex"]
 
 [params]
 
-compress/mode=2
+compress/mode=0
 compress/high_quality=false
 compress/lossy_quality=0.7
 compress/uastc_level=0
diff --git a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_orm.png.import b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_orm.png.import
index 8c320401..9bb1c5d0 100644
--- a/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_orm.png.import
+++ b/hoppys-adventure-arcade/Assets/runner/hoppy/hoppy_body_orm.png.import
@@ -3,10 +3,9 @@
 importer="texture"
 type="CompressedTexture2D"
 uid="uid://bjkoyu6nxsyci"
-path.s3tc="res://.godot/imported/hoppy_body_orm.png-a36dae46ff5d3b78351e386b721c189f.s3tc.ctex"
+path="res://.godot/imported/hoppy_body_orm.png-a36dae46ff5d3b78351e386b721c189f.ctex"
 metadata={
-"imported_formats": ["s3tc_bptc"],
-"vram_texture": true
+"vram_texture": false
 }
 generator_parameters={
 "md5": "f684053ef742dca3be2d514aacf3a5a3"
@@ -15,11 +14,11 @@ generator_parameters={
 [deps]
 
 source_file="res://Assets/runner/hoppy/hoppy_body_orm.png"
-dest_files=["res://.godot/imported/hoppy_body_orm.png-a36dae46ff5d3b78351e386b721c189f.s3tc.ctex"]
+dest_files=["res://.godot/imported/hoppy_body_orm.png-a36dae46ff5d3b78351e386b721c189f.ctex"]
 
 [params]
 
-compress/mode=2
+compress/mode=0
 compress/high_quality=false
 compress/lossy_quality=0.7
 compress/uastc_level=0
diff --git a/hoppys-adventure-arcade/app/audio_service.gd b/hoppys-adventure-arcade/app/audio_service.gd
index 563afd31..07db13d9 100644
--- a/hoppys-adventure-arcade/app/audio_service.gd
+++ b/hoppys-adventure-arcade/app/audio_service.gd
@@ -96,6 +96,19 @@ func shutdown() -> void:
 	music.stream = null
 	sfx.stream = null
 
+## Stops all audio, then waits until the audio thread has let go of every playback, so the
+## caller can quit without "leaked at exit" reports. A fixed delay races the mixer under load.
+func settle(max_seconds := 2.0) -> void:
+	var held: Array[AudioStreamPlayback] = []
+	for player: AudioStreamPlayer in [music, sfx]:
+		if player.has_stream_playback():
+			held.append(player.get_stream_playback())
+	shutdown()
+	var deadline := Time.get_ticks_msec() + int(max_seconds * 1000.0)
+	while held.any(func(playback: AudioStreamPlayback) -> bool: return playback.get_reference_count() > 1) \
+			and Time.get_ticks_msec() < deadline:
+		await get_tree().create_timer(0.02, true, false, true).timeout
+
 ## The autoload only leaves the tree when the app exits, after the current scene has left it.
 ## A voice the mixer still holds when the engine shuts down is reported as leaked ("ObjectDB
 ## instances were leaked", "resources still in use"), and a stopped voice is let go only by the
diff --git a/hoppys-adventure-arcade/tests/assets/a3_check.gd b/hoppys-adventure-arcade/tests/assets/a3_check.gd
index 2fbfb73f..8bcc8b10 100644
--- a/hoppys-adventure-arcade/tests/assets/a3_check.gd
+++ b/hoppys-adventure-arcade/tests/assets/a3_check.gd
@@ -247,6 +247,7 @@ func _run() -> void:
 	check(runtime_errors.count == 0,"no runtime errors during asset checks")
 	preload("res://scenes/runner/hazards/visuals/hazard_art.gd").release_caches()
 	print("ASSET A3: %s (%d checks)" % ["PASS" if failures == 0 else "FAIL",checks])
+	await root.get_node("AudioService").settle()
 	quit(0 if failures == 0 else 1)
 
 func _round_two(visual: Base, title: String) -> void:
diff --git a/hoppys-adventure-arcade/tests/assets/a6_check.gd b/hoppys-adventure-arcade/tests/assets/a6_check.gd
index bc5e93c0..bfb5565c 100644
--- a/hoppys-adventure-arcade/tests/assets/a6_check.gd
+++ b/hoppys-adventure-arcade/tests/assets/a6_check.gd
@@ -87,7 +87,6 @@ func run() -> void:
 	print("A6 HUNTER CENSUS: %d draws, %d triangles, no textures" % [draws,triangles])
 	print("A6 HUNTER ENVELOPE: ",envelope)
 	visual.free()
-	root.get_node("AudioService").shutdown()
-	await create_timer(0.3).timeout
+	await root.get_node("AudioService").settle()
 	print("ASSET A6: %s (%d checks)" % ["PASS" if failures == 0 else "FAIL",checks])
 	quit(0 if failures == 0 else 1)
diff --git a/hoppys-adventure-arcade/tests/assets/a9_check.gd b/hoppys-adventure-arcade/tests/assets/a9_check.gd
index 114f94ed..46397121 100644
--- a/hoppys-adventure-arcade/tests/assets/a9_check.gd
+++ b/hoppys-adventure-arcade/tests/assets/a9_check.gd
@@ -222,8 +222,7 @@ func run() -> void:
 	check(not fixture.post.settings.pursuit and value(fixture.post, "grain") > 0.0, "preview restores safe integrated defaults")
 	fixture.free()
 	if root.has_node("AudioService"):
-		root.get_node("AudioService").shutdown()
-	await create_timer(0.3).timeout
+		await root.get_node("AudioService").settle()
 	print("ASSET A9: %s (%d checks)" % ["PASS" if failures == 0 else "FAIL", checks])
 	quit(0 if failures == 0 else 1)
 
diff --git a/hoppys-adventure-arcade/tests/assets/starship_check.gd b/hoppys-adventure-arcade/tests/assets/starship_check.gd
index c1910258..6a734b1a 100644
--- a/hoppys-adventure-arcade/tests/assets/starship_check.gd
+++ b/hoppys-adventure-arcade/tests/assets/starship_check.gd
@@ -105,4 +105,5 @@ func run() -> void:
 	print("STARSHIP TOTAL: %d triangles including deck, far bulkhead, entry bulkhead and reactor dock" % (triangles + extra_triangles))
 	print("STARSHIP GEOMETRY: repeated modules=%d triangles; 6 batches; 1 shared 256x256 texture" % triangles)
 	print("STARSHIP CHECK: %s (%d checks, %d failures)" % ["PASS" if failures == 0 else "FAIL",checks,failures])
+	await root.get_node("AudioService").settle()
 	quit(0 if failures == 0 else 1)
diff --git a/hoppys-adventure-arcade/tests/beatemup_knockout.gd b/hoppys-adventure-arcade/tests/beatemup_knockout.gd
index 281f61ab..833c04f3 100644
--- a/hoppys-adventure-arcade/tests/beatemup_knockout.gd
+++ b/hoppys-adventure-arcade/tests/beatemup_knockout.gd
@@ -192,8 +192,7 @@ func run() -> void:
 	await run_mode("res://scenes/beatem_up/reinvent/heroes_vs_villains.tscn", true)
 	print("Knockout passes: ", passes, " failures: ", failures)
 	if is_instance_valid(current_scene): current_scene.queue_free()
-	root.get_node("AudioService").shutdown()
-	await create_timer(.4).timeout
+	await root.get_node("AudioService").settle()
 	quit(1 if failures else 0)
 ## Takes the scene just changed to as `game` once it has built. Without it the suite cannot go
 ## on: records a failure, quits 1 and returns false.
diff --git a/hoppys-adventure-arcade/tests/beatemup_minimap.gd b/hoppys-adventure-arcade/tests/beatemup_minimap.gd
index b91cb0fa..9d63a1de 100644
--- a/hoppys-adventure-arcade/tests/beatemup_minimap.gd
+++ b/hoppys-adventure-arcade/tests/beatemup_minimap.gd
@@ -56,8 +56,7 @@ func run() -> void:
 	print("Minimap checks: ", checks, " failures: ", failures)
 	paused = false
 	if is_instance_valid(current_scene): current_scene.queue_free()
-	root.get_node("AudioService").shutdown()
-	await create_timer(0.4).timeout
+	await root.get_node("AudioService").settle()
 	quit(1 if failures else 0)
 
 ## The pure helpers, on a standalone minimap.
diff --git a/hoppys-adventure-arcade/tests/beatemup_story.gd b/hoppys-adventure-arcade/tests/beatemup_story.gd
index 6213f198..c257dd9c 100644
--- a/hoppys-adventure-arcade/tests/beatemup_story.gd
+++ b/hoppys-adventure-arcade/tests/beatemup_story.gd
@@ -84,8 +84,7 @@ func run() -> void:
 	print("Story checks: ", checks, " failures: ", failures)
 	paused = false
 	if is_instance_valid(current_scene): current_scene.queue_free()
-	root.get_node("AudioService").shutdown()
-	await create_timer(0.4).timeout
+	await root.get_node("AudioService").settle()
 	quit(1 if failures else 0)
 
 func check_textures() -> void:
diff --git a/hoppys-adventure-arcade/tests/booth_mode.gd b/hoppys-adventure-arcade/tests/booth_mode.gd
index 74c0ea34..1f2b1318 100644
--- a/hoppys-adventure-arcade/tests/booth_mode.gd
+++ b/hoppys-adventure-arcade/tests/booth_mode.gd
@@ -86,7 +86,6 @@ func run() -> void:
 
 	router.set_booth(false)
 	router.idle_limit = router.IDLE_SECONDS
-	root.get_node("AudioService").shutdown()
-	await wait(0.4)
+	await root.get_node("AudioService").settle()
 	print("Booth mode failures: ", failures)
 	quit(1 if failures else 0)
diff --git a/hoppys-adventure-arcade/tests/code_city_assets.gd b/hoppys-adventure-arcade/tests/code_city_assets.gd
index 999cc3f3..3c4f8f07 100644
--- a/hoppys-adventure-arcade/tests/code_city_assets.gd
+++ b/hoppys-adventure-arcade/tests/code_city_assets.gd
@@ -253,6 +253,5 @@ func piece(key: String, clip: String, pos: Vector2, size: Vector2) -> void:
 	stage.add_child(sprite)
 
 func finish(code: int = 0) -> void:
-	root.get_node("AudioService").shutdown()
-	await create_timer(0.3).timeout
+	await root.get_node("AudioService").settle()
 	quit(code)
diff --git a/hoppys-adventure-arcade/tests/code_city_logic.gd b/hoppys-adventure-arcade/tests/code_city_logic.gd
index fa370e85..a453f974 100644
--- a/hoppys-adventure-arcade/tests/code_city_logic.gd
+++ b/hoppys-adventure-arcade/tests/code_city_logic.gd
@@ -222,6 +222,5 @@ func run() -> void:
 			check(InputMap.event_is_action(pad,binding[0]),"%s answers pad %d" % [binding[0],device])
 	print("Code City logic failures: ",failures)
 	game.queue_free()
-	root.get_node("AudioService").shutdown()
-	await create_timer(.4).timeout
+	await root.get_node("AudioService").settle()
 	quit(1 if failures else 0)
diff --git a/hoppys-adventure-arcade/tests/code_city_motion.gd b/hoppys-adventure-arcade/tests/code_city_motion.gd
index 5f7984b0..0d417149 100644
--- a/hoppys-adventure-arcade/tests/code_city_motion.gd
+++ b/hoppys-adventure-arcade/tests/code_city_motion.gd
@@ -1007,6 +1007,5 @@ func run() -> void:
 	check(boss.position==transition_pos and not boss.leaping and not boss.core_cue.visible,"Defeat clears movement and the exposed-core cue")
 	print("Code City motion failures: ",failures)
 	game.queue_free()
-	root.get_node("AudioService").shutdown()
-	await create_timer(.4).timeout
+	await root.get_node("AudioService").settle()
 	quit(1 if failures else 0)
diff --git a/hoppys-adventure-arcade/tests/code_city_smoke.gd b/hoppys-adventure-arcade/tests/code_city_smoke.gd
index 693fadd7..5d4a9f43 100644
--- a/hoppys-adventure-arcade/tests/code_city_smoke.gd
+++ b/hoppys-adventure-arcade/tests/code_city_smoke.gd
@@ -180,6 +180,5 @@ func run() -> void:
 	await process_frame;await process_frame
 	check(not paused and current_scene.name=="BeatemMenu","Completion returns cleanly to the mode menu")
 	current_scene.queue_free()
-	root.get_node("AudioService").shutdown()
-	await create_timer(.4).timeout
+	await root.get_node("AudioService").settle()
 	quit(1 if failures else 0)
diff --git a/hoppys-adventure-arcade/tests/enchanted_assets.gd b/hoppys-adventure-arcade/tests/enchanted_assets.gd
index cbcccd84..c5035cd7 100644
--- a/hoppys-adventure-arcade/tests/enchanted_assets.gd
+++ b/hoppys-adventure-arcade/tests/enchanted_assets.gd
@@ -102,8 +102,7 @@ func run() -> void:
 	await finish()
 
 func finish(code: int = 0) -> void:
-	root.get_node("AudioService").shutdown()
-	await create_timer(0.3).timeout
+	await root.get_node("AudioService").settle()
 	quit(code)
 
 func plate(key: String, pos: Vector2, size: Vector2, opacity: float = 1.0) -> void:
diff --git a/hoppys-adventure-arcade/tests/enchanted_boundaries.gd b/hoppys-adventure-arcade/tests/enchanted_boundaries.gd
index 6ef6e73c..30badf1b 100644
--- a/hoppys-adventure-arcade/tests/enchanted_boundaries.gd
+++ b/hoppys-adventure-arcade/tests/enchanted_boundaries.gd
@@ -80,6 +80,5 @@ func run() -> void:
 	check(current_scene.boss.hp==12 and current_scene.boss.armor_stage==0,"Actor state never mutates shared SpriteFrames")
 	change_scene_to_file("res://scenes/platformer/platformer_menu.tscn")
 	await frames(3)
-	root.get_node("AudioService").shutdown()
-	await create_timer(.3).timeout
+	await root.get_node("AudioService").settle()
 	quit(failures)
diff --git a/hoppys-adventure-arcade/tests/enchanted_repo_smoke.gd b/hoppys-adventure-arcade/tests/enchanted_repo_smoke.gd
index f3d7a85e..d07c26ae 100644
--- a/hoppys-adventure-arcade/tests/enchanted_repo_smoke.gd
+++ b/hoppys-adventure-arcade/tests/enchanted_repo_smoke.gd
@@ -284,6 +284,5 @@ func shutdown() -> void:
 	paused=false
 	change_scene_to_file("res://scenes/platformer/platformer_menu.tscn")
 	await frames(2)
-	root.get_node("AudioService").shutdown()
-	await create_timer(.3).timeout
+	await root.get_node("AudioService").settle()
 	quit(failures)
diff --git a/hoppys-adventure-arcade/tests/heroes_villains_assets.gd b/hoppys-adventure-arcade/tests/heroes_villains_assets.gd
index 1a164754..c08a9615 100644
--- a/hoppys-adventure-arcade/tests/heroes_villains_assets.gd
+++ b/hoppys-adventure-arcade/tests/heroes_villains_assets.gd
@@ -95,6 +95,5 @@ func run() -> void:
 	else:
 		printerr(failures, " asset checks failed")
 	resources.clear()
-	root.get_node("AudioService").shutdown()
-	await create_timer(0.3).timeout
+	await root.get_node("AudioService").settle()
 	quit(0 if failures == 0 else 1)
diff --git a/hoppys-adventure-arcade/tests/heroes_villains_logic.gd b/hoppys-adventure-arcade/tests/heroes_villains_logic.gd
index 1544d8f0..354dadb6 100644
--- a/hoppys-adventure-arcade/tests/heroes_villains_logic.gd
+++ b/hoppys-adventure-arcade/tests/heroes_villains_logic.gd
@@ -427,7 +427,6 @@ func run() -> void:
 	game.victory._input(advance_key())
 	check(game.leaving,"Dedicated advance presses Return once the count has landed")
 	game.queue_free();await process_frame
-	root.get_node("AudioService").shutdown()
-	await create_timer(.3).timeout
+	await root.get_node("AudioService").settle()
 	print("Heroes vs. Villains logic failures: ",failures)
 	quit(0 if failures==0 else 1)
diff --git a/hoppys-adventure-arcade/tests/heroes_villains_motion.gd b/hoppys-adventure-arcade/tests/heroes_villains_motion.gd
index 640f4b96..42f650b1 100644
--- a/hoppys-adventure-arcade/tests/heroes_villains_motion.gd
+++ b/hoppys-adventure-arcade/tests/heroes_villains_motion.gd
@@ -422,9 +422,9 @@ func run() -> void:
 	print("Heroes vs. Villains motion failures: ",failures)
 	for voice in game.sound_pool: voice.stop()
 	game.music.stop()
-	root.get_node("AudioService").shutdown()
 	game.queue_free()
 	await process_frame;await process_frame
+	await root.get_node("AudioService").settle()
 	quit(1 if failures else 0)
 
 const ENCOUNTER := "ENCOUNTER 1 / 3 — clear the blockers"
diff --git a/hoppys-adventure-arcade/tests/heroes_villains_smoke.gd b/hoppys-adventure-arcade/tests/heroes_villains_smoke.gd
index 7074c6ba..c3921a33 100644
--- a/hoppys-adventure-arcade/tests/heroes_villains_smoke.gd
+++ b/hoppys-adventure-arcade/tests/heroes_villains_smoke.gd
@@ -168,6 +168,6 @@ func run() -> void:
 		if is_instance_valid(current_scene) and current_scene.scene_file_path.ends_with("beatem_menu.tscn") and not root.get_node("AppRouter").busy: break
 	check(current_scene.scene_file_path.ends_with("beatem_menu.tscn") and not paused,"Victory returns to an unpaused mode menu")
 	current_scene.queue_free();await process_frame
-	root.get_node("AudioService").shutdown();await create_timer(.3).timeout
+	await root.get_node("AudioService").settle()
 	print("Heroes vs. Villains smoke failures: ",failures)
 	quit(0 if failures==0 else 1)
diff --git a/hoppys-adventure-arcade/tests/menu_hoppy_smoke.gd b/hoppys-adventure-arcade/tests/menu_hoppy_smoke.gd
index 428d60ad..4144fbb7 100644
--- a/hoppys-adventure-arcade/tests/menu_hoppy_smoke.gd
+++ b/hoppys-adventure-arcade/tests/menu_hoppy_smoke.gd
@@ -51,6 +51,5 @@ func run() -> void:
 	check(hoppy.runner.process_mode == Node.PROCESS_MODE_DISABLED, "Hidden rig stops processing")
 	check(hoppy.get_child_count() == 3, "Switching reuses portrait nodes")
 	print("MENU HOPPY SMOKE: ", "PASS" if failures == 0 else "FAIL", " (", failures, " failures)")
-	root.get_node("AudioService").shutdown()
-	await wait(0.3)
+	await root.get_node("AudioService").settle()
 	quit(failures)
diff --git a/hoppys-adventure-arcade/tests/menu_return_layout.gd b/hoppys-adventure-arcade/tests/menu_return_layout.gd
index e23e2685..5ba08927 100644
--- a/hoppys-adventure-arcade/tests/menu_return_layout.gd
+++ b/hoppys-adventure-arcade/tests/menu_return_layout.gd
@@ -104,6 +104,5 @@ func run() -> void:
 	await settle()
 	await check_menu("retry-platformer-hub")
 	print("MENU RETURN: ", "PASS" if failures == 0 else "FAIL", " (", failures, " failures)")
-	root.get_node("AudioService").shutdown()
-	await wait(0.3)
+	await root.get_node("AudioService").settle()
 	quit(failures)
diff --git a/hoppys-adventure-arcade/tests/orbital_assets.gd b/hoppys-adventure-arcade/tests/orbital_assets.gd
index e19672e0..2a24bcdb 100644
--- a/hoppys-adventure-arcade/tests/orbital_assets.gd
+++ b/hoppys-adventure-arcade/tests/orbital_assets.gd
@@ -98,8 +98,7 @@ func run() -> void:
 	await finish()
 
 func finish(code: int = 0) -> void:
-	root.get_node("AudioService").shutdown()
-	await create_timer(0.3).timeout
+	await root.get_node("AudioService").settle()
 	quit(code)
 
 func plate(key: String, pos: Vector2, size: Vector2, opacity: float = 1.0) -> void:
diff --git a/hoppys-adventure-arcade/tests/orbital_ops_smoke.gd b/hoppys-adventure-arcade/tests/orbital_ops_smoke.gd
index 56e9fefb..99fb1ec3 100644
--- a/hoppys-adventure-arcade/tests/orbital_ops_smoke.gd
+++ b/hoppys-adventure-arcade/tests/orbital_ops_smoke.gd
@@ -286,6 +286,5 @@ func shutdown() -> void:
 	paused=false
 	change_scene_to_file("res://scenes/platformer/platformer_menu.tscn")
 	await frames(2)
-	root.get_node("AudioService").shutdown()
-	await create_timer(.3).timeout
+	await root.get_node("AudioService").settle()
 	quit(failures)
diff --git a/hoppys-adventure-arcade/tests/perf_probe.gd b/hoppys-adventure-arcade/tests/perf_probe.gd
index 73b2b320..27599dc7 100644
--- a/hoppys-adventure-arcade/tests/perf_probe.gd
+++ b/hoppys-adventure-arcade/tests/perf_probe.gd
@@ -92,6 +92,5 @@ func run() -> void:
 	router.go("hub")
 	await worst(60)
 	report("swap_to_hub")
-	root.get_node("AudioService").shutdown()
-	await create_timer(0.2).timeout
+	await root.get_node("AudioService").settle()
 	quit(0)
diff --git a/hoppys-adventure-arcade/tests/platformer_boss.gd b/hoppys-adventure-arcade/tests/platformer_boss.gd
index ddfef26d..38634eb5 100644
--- a/hoppys-adventure-arcade/tests/platformer_boss.gd
+++ b/hoppys-adventure-arcade/tests/platformer_boss.gd
@@ -135,6 +135,5 @@ func run() -> void:
 	print("BOSS TEST: ", "PASS" if failures == 0 else "FAIL", " (", failures, " failures)")
 	change_scene_to_file("res://scenes/platformer/platformer_menu.tscn")
 	await frames(2)
-	root.get_node("AudioService").shutdown()
-	await create_timer(0.4).timeout
+	await root.get_node("AudioService").settle()
 	quit(failures)
diff --git a/hoppys-adventure-arcade/tests/platformer_smoke.gd b/hoppys-adventure-arcade/tests/platformer_smoke.gd
index d2ed2760..6f897efd 100644
--- a/hoppys-adventure-arcade/tests/platformer_smoke.gd
+++ b/hoppys-adventure-arcade/tests/platformer_smoke.gd
@@ -182,6 +182,5 @@ func run() -> void:
 	check(not root.get_node("AudioService").music.stream_paused, "Menu music restored")
 	print("PLATFORMER SMOKE: ", "PASS" if failures == 0 else "FAIL", " (", failures, " failures)")
 	await frames(35)
-	root.get_node("AudioService").shutdown()
-	await create_timer(0.3).timeout
+	await root.get_node("AudioService").settle()
 	quit(failures)
diff --git a/hoppys-adventure-arcade/tests/platformer_traversal.gd b/hoppys-adventure-arcade/tests/platformer_traversal.gd
index 8915c0a2..fefcc02c 100644
--- a/hoppys-adventure-arcade/tests/platformer_traversal.gd
+++ b/hoppys-adventure-arcade/tests/platformer_traversal.gd
@@ -90,8 +90,7 @@ func run() -> void:
 			child.stream = null
 	level.music.stop()
 	level.music.stream = null
-	root.get_node("AudioService").shutdown()
-	await create_timer(0.3).timeout
-	# Audio cleanup uses wall time even in accelerated --fixed-fps test runs.
+	await root.get_node("AudioService").settle()
+	# The level's own player still releases on wall time in accelerated --fixed-fps runs.
 	OS.delay_msec(300)
 	quit(failures)
diff --git a/hoppys-adventure-arcade/tests/runner_boss_validator.gd b/hoppys-adventure-arcade/tests/runner_boss_validator.gd
index 99c78b91..5f3bca6c 100644
--- a/hoppys-adventure-arcade/tests/runner_boss_validator.gd
+++ b/hoppys-adventure-arcade/tests/runner_boss_validator.gd
@@ -915,4 +915,8 @@ func _report() -> void:
 	player = null
 	tool_node = null
 	print("RUNNER BOSS: ", "PASS" if failures == 0 else "FAIL", " (", failures, " failures / ", checks, " checks)")
-	quit(failures)
+	_quit_quietly(failures)
+
+func _quit_quietly(code: int) -> void:
+	await root.get_node("AudioService").settle()
+	quit(code)
diff --git a/hoppys-adventure-arcade/tests/runner_chunk_validator.gd b/hoppys-adventure-arcade/tests/runner_chunk_validator.gd
index aa5258da..b42183af 100644
--- a/hoppys-adventure-arcade/tests/runner_chunk_validator.gd
+++ b/hoppys-adventure-arcade/tests/runner_chunk_validator.gd
@@ -1133,4 +1133,8 @@ func _report() -> void:
 	junk.clear()
 	wall_scene = null
 	print("RUNNER CHUNKS: ", "PASS" if failures == 0 else "FAIL", " (", failures, " failures / ", checks, " checks)")
-	quit(failures)
+	_quit_quietly(failures)
+
+func _quit_quietly(code: int) -> void:
+	await root.get_node("AudioService").settle()
+	quit(code)
diff --git a/hoppys-adventure-arcade/tests/runner_logic.gd b/hoppys-adventure-arcade/tests/runner_logic.gd
index c77281ad..de7af293 100644
--- a/hoppys-adventure-arcade/tests/runner_logic.gd
+++ b/hoppys-adventure-arcade/tests/runner_logic.gd
@@ -3787,4 +3787,8 @@ func _report() -> void:
 	spawner_script = null
 	player_script = null
 	print("RUNNER LOGIC: ", "PASS" if failures == 0 else "FAIL", " (", failures, " failures / ", checks, " checks)")
-	quit(failures)
+	_quit_quietly(failures)
+
+func _quit_quietly(code: int) -> void:
+	await root.get_node("AudioService").settle()
+	quit(code)
diff --git a/hoppys-adventure-arcade/tests/runner_visual_smoke.gd b/hoppys-adventure-arcade/tests/runner_visual_smoke.gd
index 9726348e..477a59af 100644
--- a/hoppys-adventure-arcade/tests/runner_visual_smoke.gd
+++ b/hoppys-adventure-arcade/tests/runner_visual_smoke.gd
@@ -336,8 +336,7 @@ func run() -> void:
 	await check_runner_audio()
 	await check_runner_full_loop()
 	await check_runner_menu_reset()
-	root.get_node("AudioService").shutdown()
-	await create_timer(0.3).timeout
+	await root.get_node("AudioService").settle()
 	failures += _logger.errors()
 	print("RUNNER VISUAL SMOKE: ", "PASS" if failures == 0 else "FAIL", " (", failures, " failures)")
 	OS.remove_logger(_logger)
diff --git a/hoppys-adventure-arcade/tests/stage_flow.gd b/hoppys-adventure-arcade/tests/stage_flow.gd
index b59624cb..50ea84f7 100644
--- a/hoppys-adventure-arcade/tests/stage_flow.gd
+++ b/hoppys-adventure-arcade/tests/stage_flow.gd
@@ -104,8 +104,7 @@ func run() -> void:
 	await check_armed_overlays()
 	print("Stage flow failures: ", failures)
 	if is_instance_valid(current_scene): current_scene.queue_free()
-	root.get_node("AudioService").shutdown()
-	await create_timer(.4).timeout
+	await root.get_node("AudioService").settle()
 	quit(1 if failures else 0)
 ## Accumulated 1/60 steps land one ulp under 4.5, so the page turns on the next tick.
 func cross_intro(page: int) -> void:
diff --git a/hoppys-adventure-arcade/tools/blender/bosses/boss_kit.py b/hoppys-adventure-arcade/tools/blender/bosses/boss_kit.py
index 03abf461..79147346 100644
--- a/hoppys-adventure-arcade/tools/blender/bosses/boss_kit.py
+++ b/hoppys-adventure-arcade/tools/blender/bosses/boss_kit.py
@@ -7,6 +7,7 @@
 """
 import hashlib
 import json
+import math
 import os
 from pathlib import Path
 import random
@@ -17,14 +18,14 @@
 import tempfile
 
 import bpy
-from mathutils import Matrix, Vector
+from mathutils import Euler, Matrix, Vector
 
 HERE = Path(__file__).resolve().parent
 DEFAULT_ASSET_DIR = HERE.parent.parent.parent / 'Assets' / 'runner' / 'bosses'
 sys.path.insert(0, str(HERE.parent))
 sys.path.insert(0, str(HERE.parent / 'props'))
 import props_kit as P
-from props_kit import Part as Part, linear, xform, G2B, B2G
+from props_kit import Part, linear, xform, G2B, B2G
 from glb_atlas import consolidate_atlases
 
 SEED = 73019
diff --git a/hoppys-adventure-arcade/tools/blender/bosses/build_legacy_monolith.py b/hoppys-adventure-arcade/tools/blender/bosses/build_legacy_monolith.py
index 4b081dc1..ccf299f8 100644
--- a/hoppys-adventure-arcade/tools/blender/bosses/build_legacy_monolith.py
+++ b/hoppys-adventure-arcade/tools/blender/bosses/build_legacy_monolith.py
@@ -7,7 +7,7 @@
 import sys
 
 sys.path.insert(0, str(Path(__file__).resolve().parent))
-from boss_kit import DEFAULT_ASSET_DIR, BossBuilder, Part, xform
+from boss_kit import DEFAULT_ASSET_DIR, BossBuilder, Part, xform, require
 
 RECIPE_REVISION = 3
 RACK_Y = (-0.47, 0.34, 1.32, 2.68)
diff --git a/hoppys-adventure-arcade/tools/blender/bosses/build_merge_conflict_hydra.py b/hoppys-adventure-arcade/tools/blender/bosses/build_merge_conflict_hydra.py
index deb2702e..350d6728 100644
--- a/hoppys-adventure-arcade/tools/blender/bosses/build_merge_conflict_hydra.py
+++ b/hoppys-adventure-arcade/tools/blender/bosses/build_merge_conflict_hydra.py
@@ -2,10 +2,11 @@
 import argparse
 import bpy
 import hashlib
+import json
 import math
 from pathlib import Path
 import sys
-from mathutils import Vector
+from mathutils import Matrix, Vector
 sys.path.insert(0, str(Path(__file__).resolve().parent))
 from boss_kit import DEFAULT_ASSET_DIR, BossBuilder, Part, xform, B2G
 
diff --git a/ruff.toml b/ruff.toml
index 72b777e8..3b983d38 100644
--- a/ruff.toml
+++ b/ruff.toml
@@ -1,3 +1,9 @@
 # Baseline: pyflakes errors only (undefined names, unused imports). Tighten over time.
 [lint]
 select = ["F"]
+
+[lint.per-file-ignores]
+# Each boss GLB records the SHA-256 of these recipe sources (boss_kit.py export), and
+# tests/assets/boss_legacy_monolith_check.gd fails when a source no longer matches. Leave their
+# unused imports until the next rebake, so a lint fix doesn't drift them from the committed models.
+"hoppys-adventure-arcade/tools/blender/bosses/{boss_kit,build_legacy_monolith,build_merge_conflict_hydra}.py" = ["F401"]
diff --git a/tools/tests/run_tests.py b/tools/tests/run_tests.py
new file mode 100644
index 00000000..a6cd8df8
--- /dev/null
+++ b/tools/tests/run_tests.py
@@ -0,0 +1,318 @@
+"""Run every Godot test suite headless and fail on anything the engine reports.
+
+Usage:
+    python3 tools/tests/run_tests.py                     # all suites, in parallel
+    python3 tools/tests/run_tests.py -k runner -j 2      # suites whose name contains "runner"
+    python3 tools/tests/run_tests.py --list              # what would run, and what is skipped
+
+Every .gd file under hoppys-adventure-arcade/tests/ that extends SceneTree (or MainLoop) is a
+suite and runs by default; new tests need no registration. Other scripts there are helpers.
+tools/tests/suites.toml is the only way to keep a suite out, and each skip carries a reason.
+A suite fails if it exits nonzero, times out, or prints an engine/script error or an exit-time
+leak. Errors a suite provokes on purpose are allowed only through its expected_errors patterns,
+and every listed pattern must still match. Suites listed under [serial] (timing budgets) run one
+at a time after the parallel batch.
+
+Each suite gets its own HOME, so user:// writes (settings, leaderboards) never touch the
+developer's real files or another suite running in parallel. Standard library only.
+"""
+from __future__ import annotations
+
+import argparse
+import json
+import os
+import re
+import shutil
+import subprocess
+import sys
+import tempfile
+import time
+import tomllib
+from concurrent.futures import ThreadPoolExecutor, as_completed
+from dataclasses import dataclass, field
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[2]
+PROJECT = ROOT / "hoppys-adventure-arcade"
+TESTS = PROJECT / "tests"
+CONFIG = Path(__file__).with_name("suites.toml")
+TIMEOUT = 600
+ANSI = re.compile(r"\x1b\[[0-9;]*m")
+# Lines that mean something went wrong even when a suite's own checks all passed.
+PROBLEM = re.compile(
+    r"^(?:ERROR:|SCRIPT ERROR|USER ERROR|Parse Error)"
+    r"|Failed to load script|leaked at exit|still in use at exit"
+)
+
+
+@dataclass
+class Result:
+    name: str
+    seconds: float
+    exit_code: int | None
+    problems: list[str] = field(default_factory=list)
+    log: str = ""
+    notes: list[str] = field(default_factory=list)
+
+    @property
+    def passed(self) -> bool:
+        """A clean exit with nothing in the log that fails a suite."""
+        return self.exit_code == 0 and not self.problems
+
+
+# Godot can only run a script that extends SceneTree or MainLoop with --script; anything else
+# under tests/ (shared helpers, fixtures) is support code, and running it pops a modal alert.
+SUITE_BASE = re.compile(r"^extends\s+(?:SceneTree|MainLoop)\b", re.M)
+
+
+def discover() -> list[str]:
+    """Suite names are paths under tests/ without .gd, e.g. "runner_logic" or "assets/a1_check"."""
+    return sorted(
+        path.relative_to(TESTS).with_suffix("").as_posix()
+        for path in TESTS.rglob("*.gd")
+        if SUITE_BASE.search(path.read_text(encoding="utf-8", errors="replace"))
+    )
+
+
+@dataclass
+class Config:
+    skip: dict[str, str]
+    serial: dict[str, str]
+    expected: dict[str, list[re.Pattern[str]]]
+    errors: list[str]
+
+
+def load_config(suites: list[str], text: str | None = None) -> Config:
+    """Read suites.toml (or `text`); every entry must name a suite, and skips and serials need a reason."""
+    raw = tomllib.loads(CONFIG.read_text(encoding="utf-8") if text is None else text)
+    skip: dict[str, str] = raw.get("skip", {})
+    serial: dict[str, str] = raw.get("serial", {})
+    expected = {name: [re.compile(p) for p in patterns] for name, patterns in raw.get("expected_errors", {}).items()}
+    errors = [f"{CONFIG.name}: [{section}] names {name!r}, which is not a suite"
+              for section, names in (("skip", skip), ("serial", serial), ("expected_errors", expected))
+              for name in names if name not in suites]
+    errors += [f"{CONFIG.name}: [{section}] entry {name!r} needs a reason"
+               for section, table in (("skip", skip), ("serial", serial))
+               for name, reason in table.items() if not reason.strip()]
+    return Config(skip, serial, expected, errors)
+
+
+def isolated_env(home: str) -> dict[str, str]:
+    """Point every platform's user-data root (user://) at a private directory."""
+    return {**os.environ, "HOME": home, "USERPROFILE": home,
+            "XDG_DATA_HOME": f"{home}/.local/share", "XDG_CONFIG_HOME": f"{home}/.config",
+            "XDG_CACHE_HOME": f"{home}/.cache",
+            "APPDATA": str(Path(home, "AppData", "Roaming")), "LOCALAPPDATA": str(Path(home, "AppData", "Local"))}
+
+
+def check_isolation(godot: str) -> str | None:
+    """Ask Godot where user:// resolves under the isolated environment; None when it is private."""
+    home = tempfile.mkdtemp(prefix="arcade-test-probe-")
+    try:
+        probe = Path(home, "probe.gd")
+        probe.write_text('extends SceneTree\nfunc _init() -> void:\n\tprint("USER_DIR=", OS.get_user_data_dir())\n'
+                         '\tquit()\n', encoding="utf-8")
+        try:
+            output = subprocess.run([godot, "--headless", "--path", str(PROJECT), "--script", str(probe)],
+                                    env=isolated_env(home), capture_output=True, text=True, timeout=120).stdout
+        except (OSError, subprocess.TimeoutExpired) as error:
+            return f"the user:// probe could not run ({error})"
+        match = re.search(r"^USER_DIR=(.+)$", ANSI.sub("", output), re.M)
+        user_dir = Path(match.group(1).strip()).resolve() if match else None
+        if user_dir is None or Path(home).resolve() not in user_dir.parents:
+            return f"user:// resolved to {user_dir or 'nothing'}, outside the isolated home {home}"
+        return None
+    finally:
+        shutil.rmtree(home, ignore_errors=True)
+
+
+LEAK = re.compile(r"leaked at exit|still in use at exit")
+# The engine's two summary lines whose --verbose detail lines classify_leaks() reads. Any other exit
+# leak report (RID allocations, for one) has no such detail and is never tolerated.
+LEAK_SUMMARY = re.compile(r"ObjectDB instances were leaked at exit|resources still in use at exit")
+LEAKED_INSTANCE = re.compile(r"^Leaked instance: (\w+):", re.M)
+RESOURCE_IN_USE = re.compile(r"^Resource still in use: (.+) \((\w+)\)$", re.M)
+# The engine releases audio playbacks on its audio thread. When a suite quits while that thread
+# is starved (parallel 3D suites on a small CI runner), the shared music and UI voices are
+# reported as leaked even after AudioService.settle(). Only that exact shape is tolerated:
+# audio stream classes (AudioStream*, and Ogg Vorbis's internal OggPacketSequence*) and audio
+# files still in use. Any other leaked object fails the suite.
+AUDIO_CLASS = re.compile(r"^(?:AudioStream\w*|OggPacketSequence\w*)$")
+VERBOSE_NOISE = re.compile(r"^(?:Loading resource:|Completed load for:|Loaded builtin|Loading |  ->|ResourceFormat)")
+
+
+def classify_leaks(log: str) -> tuple[bool, list[str]]:
+    """(is the audio-teardown race, detail lines naming what leaked) from a --verbose log."""
+    instances = LEAKED_INSTANCE.findall(log)
+    resources = RESOURCE_IN_USE.findall(log)
+    unclassified = [line.strip() for line in log.splitlines() if LEAK.search(line) and not LEAK_SUMMARY.search(line)]
+    details = [f"leaked: {name}" for name in instances] + [f"still in use: {path} ({kind})" for path, kind in resources]
+    audio_only = bool(details) and not unclassified and all(AUDIO_CLASS.match(name) for name in instances) \
+        and all(AUDIO_CLASS.match(kind) for _, kind in resources)
+    return audio_only, details + unclassified
+
+
+def run_suite(godot: str, name: str, expected: list[re.Pattern[str]]) -> Result:
+    """Run one suite and classify any exit leak: only the audio-teardown race becomes a note."""
+    result = run_once(godot, name, expected)
+    if any(LEAK.search(problem) for problem in result.problems):
+        audio_only, details = classify_leaks(result.log)
+        if audio_only:
+            result.problems = [problem for problem in result.problems if not LEAK_SUMMARY.search(problem)]
+            result.notes.append("engine audio-teardown race tolerated: " + ", ".join(details))
+        else:
+            result.problems += details[:20] or ["leak with no --verbose detail"]
+    result.log = "\n".join(line for line in result.log.splitlines() if not VERBOSE_NOISE.match(line))
+    return result
+
+
+def run_once(godot: str, name: str, expected: list[re.Pattern[str]]) -> Result:
+    """One headless, --verbose run of res://tests/<name>.gd with a private user-data root."""
+    home = tempfile.mkdtemp(prefix="arcade-test-home-")
+    env = isolated_env(home)
+    # --verbose makes Godot name what leaked in the same run, so a leak can be classified.
+    command = [godot, "--headless", "--verbose", "--path", str(PROJECT), "--script", f"res://tests/{name}.gd"]
+    started = time.monotonic()
+    try:
+        completed = subprocess.run(command, env=env, capture_output=True, text=True, timeout=TIMEOUT)
+        exit_code, log = completed.returncode, ANSI.sub("", completed.stdout + completed.stderr)
+    except subprocess.TimeoutExpired as timeout:
+        output = timeout.stdout or b""
+        exit_code, log = None, ANSI.sub("", output.decode() if isinstance(output, bytes) else output)
+    finally:
+        shutil.rmtree(home, ignore_errors=True)
+    return Result(name, time.monotonic() - started, exit_code, find_problems(log, exit_code, expected), log)
+
+
+def find_problems(log: str, exit_code: int | None, expected: list[re.Pattern[str]]) -> list[str]:
+    """Everything that fails a suite besides its exit code: engine errors, leaks, stale expectations."""
+    problems = [] if exit_code is not None else [f"timed out after {TIMEOUT}s"]
+    lines = log.splitlines()
+    problems += [line.strip() for line in lines
+                 if PROBLEM.search(line) and not any(pattern.search(line) for pattern in expected)]
+    problems += [f"expected error no longer occurs; remove it from {CONFIG.name}: {pattern.pattern}"
+                 for pattern in expected if not any(pattern.search(line) for line in lines)]
+    return problems
+
+
+def annotate(result: Result) -> None:
+    """Report a failed suite as a GitHub Actions error annotation (no-op outside Actions)."""
+    if os.environ.get("GITHUB_ACTIONS") != "true":
+        return
+    detail = "%0A".join(dict.fromkeys(result.problems))[:4000] or f"exit {result.exit_code}"
+    print(f"::error title=tests/{result.name}.gd::{detail}")
+
+
+def write_summary(path: Path, seconds: float, skipped: dict[str, str], results: list[Result],
+                  setup_error: str | None = None) -> None:
+    """Write the JSON results summary. A setup failure (isolation, import) is recorded with no suites."""
+    summary: dict[str, object] = {
+        "seconds": round(seconds, 1),
+        "skipped": skipped,
+        "suites": [{"name": r.name, "passed": r.passed, "exit_code": r.exit_code, "seconds": round(r.seconds, 1),
+                    "problems": list(dict.fromkeys(r.problems)), "notes": r.notes}
+                   for r in sorted(results, key=lambda r: r.name)],
+    }
+    if setup_error is not None:
+        summary["setup_error"] = setup_error
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_text(json.dumps(summary, indent=2) + "\n", encoding="utf-8")
+
+
+def main() -> int:
+    """Discover, filter and run the suites; returns 0 if all pass, 1 on a failure, 2 on a usage or setup error."""
+    parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+    parser.add_argument("--godot", default=os.environ.get("GODOT", "godot"),
+                        help="Godot 4.7.1 binary (default: $GODOT or godot)")
+    parser.add_argument("-k", dest="match", action="append", default=[],
+                        help="run suites whose name contains this text")
+    parser.add_argument("-j", "--jobs", type=int, default=min(4, os.cpu_count() or 1), help="suites to run at once")
+    parser.add_argument("--no-import", action="store_true", help="skip the resource import step")
+    parser.add_argument("--list", action="store_true", help="print the plan and exit")
+    parser.add_argument("--results", type=Path, default=ROOT / "build/test-results/summary.json")
+    args = parser.parse_args()
+
+    suites = discover()
+    config = load_config(suites)
+    if config.errors:
+        print("\n".join(config.errors), file=sys.stderr)
+        return 2
+    skips, expected = config.skip, config.expected
+    selected = [s for s in suites if not args.match or any(m in s for m in args.match)]
+    planned = [s for s in selected if s not in skips]
+    if args.list:
+        for suite in selected:
+            if suite in skips:
+                print(f"skip    {suite}: {skips[suite]}")
+            elif suite in config.serial:
+                print(f"serial  {suite}: {config.serial[suite]}")
+            else:
+                print(f"run     {suite}")
+        return 0
+    if not planned:
+        print("No suites selected.", file=sys.stderr)
+        return 2
+    skipped = {name: skips[name] for name in selected if name in skips}
+
+    leak = check_isolation(args.godot)
+    if leak:
+        print(f"Refusing to run: {leak}. Suites must not touch real settings or leaderboards.", file=sys.stderr)
+        write_summary(args.results, 0.0, skipped, [], f"user:// isolation: {leak}")
+        return 2
+
+    if not args.no_import:
+        home = tempfile.mkdtemp(prefix="arcade-test-import-")
+        try:
+            imported = subprocess.run([args.godot, "--headless", "--path", str(PROJECT), "--import"],
+                                      env=isolated_env(home), capture_output=True, text=True, timeout=TIMEOUT)
+        except (OSError, subprocess.TimeoutExpired) as error:
+            print(f"Resource import failed: {error}", file=sys.stderr)
+            write_summary(args.results, 0.0, skipped, [], f"resource import failed: {error}")
+            return 1
+        finally:
+            shutil.rmtree(home, ignore_errors=True)
+        import_log = ANSI.sub("", imported.stdout + imported.stderr)
+        import_problems = find_problems(import_log, imported.returncode, [])
+        if imported.returncode != 0 or import_problems:
+            print(import_log[-4000:], file=sys.stderr)
+            print("Resource import failed:", *dict.fromkeys(import_problems), sep="\n  ", file=sys.stderr)
+            reasons = list(dict.fromkeys(import_problems)) or [f"exit {imported.returncode}"]
+            write_summary(args.results, 0.0, skipped, [], "resource import failed: " + "; ".join(reasons))
+            return 1
+
+    parallel = [s for s in planned if s not in config.serial]
+    serial = [s for s in planned if s in config.serial]
+    print(f"Running {len(planned)} suites ({len(selected) - len(planned)} skipped): "
+          f"{len(parallel)} at {args.jobs} a time, then {len(serial)} alone.")
+    started = time.monotonic()
+    results: list[Result] = []
+
+    def record(result: Result) -> None:
+        results.append(result)
+        note = f"  [{result.notes[0][:120]}]" if result.notes else ""
+        print(f"{'PASS' if result.passed else 'FAIL'}  {result.name}  ({result.seconds:.0f}s){note}", flush=True)
+
+    with ThreadPoolExecutor(max_workers=max(1, args.jobs)) as pool:
+        futures = [pool.submit(run_suite, args.godot, s, expected.get(s, [])) for s in parallel]
+        for future in as_completed(futures):
+            record(future.result())
+    # Suites with timing budgets run on an otherwise idle machine.
+    for suite in serial:
+        record(run_suite(args.godot, suite, expected.get(suite, [])))
+
+    failed = sorted((r for r in results if not r.passed), key=lambda r: r.name)
+    for result in failed:
+        print(f"\n--- {result.name}: exit {result.exit_code}")
+        for problem in dict.fromkeys(result.problems):
+            print(f"    {problem}")
+        print("    last output:\n" + "\n".join(f"      {line}" for line in result.log.splitlines()[-25:]))
+        annotate(result)
+
+    write_summary(args.results, time.monotonic() - started, skipped, results)
+    print(f"\n{len(results) - len(failed)} passed, {len(failed)} failed, "
+          f"{len(selected) - len(planned)} skipped in {time.monotonic() - started:.0f}s")
+    return 1 if failed else 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/tools/tests/suites.toml b/tools/tests/suites.toml
new file mode 100644
index 00000000..5f3f47e9
--- /dev/null
+++ b/tools/tests/suites.toml
@@ -0,0 +1,27 @@
+# Configuration for tools/tests/run_tests.py.
+#
+# Every suite (a script under hoppys-adventure-arcade/tests/ that extends SceneTree or MainLoop)
+# runs headless in CI by default.
+# A [skip] entry is the only way to keep a suite out, and it must say why.
+
+[skip]
+capture_runner_menu_previews = "Writes menu preview screenshots; needs a window and GPU. Run it locally without --headless."
+perf_probe = "Measures GPU frame times, which are meaningless headless. Run it locally."
+runner_perf_probe = "Measures runner frame times on a GPU. Run it locally."
+runner_pickup_hitch = "Measures GPU hitches during pickups. Run it locally."
+menu_smoke = "Drives the menu with pointer hover, which a headless run never produces."
+menu_hoppy_smoke = "Drives the menu with pointer hover, which a headless run never produces."
+capture_code_city_bosses = "Writes the Code City boss stills into docs/previews/; a graphical run only."
+exit_leak = "Needs a --scenario per process; CI runs every scenario through tools/checks/exit_leak.py."
+
+# Suites with wall-clock budgets, or that occupy every core, run alone after the parallel
+# batch, so CPU contention from other suites can't fail them (or them, the others).
+[serial]
+"assets/prewarm_check" = "Asserts the runner's synchronous cold warm finishes under 1000 ms."
+"assets/a2_check" = "Waits at most 15 s for the asynchronous prewarm, which the parallel batch starves on a 2-core runner."
+runner_synth_threads = "Parks a thread on every core and releases them together; it needs idle cores and starves other suites."
+
+# Engine errors a suite triggers on purpose. Each pattern must match at least one line of
+# that suite's output, so the list can't outlive the behavior it describes.
+[expected_errors]
+runner_logic = ['^ERROR: ConfigFile parse error at user://test_leaderboard_']
diff --git a/tools/tests/test_run_tests.py b/tools/tests/test_run_tests.py
new file mode 100644
index 00000000..62628f85
--- /dev/null
+++ b/tools/tests/test_run_tests.py
@@ -0,0 +1,166 @@
+"""Unit tests for run_tests.py's discovery, configuration checks and failure detection."""
+import contextlib
+import io
+import json
+import re
+import subprocess
+import tempfile
+import unittest
+from pathlib import Path
+from unittest import mock
+
+import run_tests
+
+
+class FindProblems(unittest.TestCase):
+    def test_clean_log_has_no_problems(self):
+        self.assertEqual(run_tests.find_problems("PASS: thing\nAll good\n", 0, []), [])
+
+    def test_engine_and_script_errors_fail(self):
+        log = "SCRIPT ERROR: Invalid call\nERROR: Condition failed\nParse Error: bad\n"
+        self.assertEqual(len(run_tests.find_problems(log, 0, [])), 3)
+
+    def test_exit_leaks_fail(self):
+        log = ("WARNING: 3 ObjectDB instances were leaked at exit (run with `--verbose` for details).\n"
+               "ERROR: 1 resources still in use at exit (run with --verbose for details).\n")
+        self.assertEqual(len(run_tests.find_problems(log, 0, [])), 2)
+
+    def test_ordinary_warnings_and_file_names_pass(self):
+        log = "WARNING: leaderboard schema newer\nStoring File: sfx_sounds_error1.wav\n"
+        self.assertEqual(run_tests.find_problems(log, 0, []), [])
+
+    def test_expected_errors_are_allowed_but_must_still_occur(self):
+        expected = [re.compile(r"^ERROR: ConfigFile parse error")]
+        self.assertEqual(run_tests.find_problems("ERROR: ConfigFile parse error at x\n", 0, expected), [])
+        stale = run_tests.find_problems("all fine\n", 0, expected)
+        self.assertEqual(len(stale), 1)
+        self.assertIn("no longer occurs", stale[0])
+
+    def test_timeout_is_a_problem(self):
+        self.assertIn("timed out", run_tests.find_problems("", None, [])[0])
+
+
+class ClassifyLeaks(unittest.TestCase):
+    AUDIO = ("Leaked instance: AudioStreamPlaybackMP3:1 - Reference count: 1\n"
+             "Leaked instance: AudioStreamPlaybackPolyphonic:2 - Reference count: 1\n"
+             "Resource still in use: res://Assets/Audio/Main Menu/track.mp3 (AudioStreamMP3)\n")
+
+    def test_ogg_internals_count_as_audio(self):
+        log = ("Leaked instance: OggPacketSequence:1 - Reference count: 3\n"
+               "Leaked instance: OggPacketSequencePlayback:2 - Reference count: 1\n"
+               "Leaked instance: AudioStreamOggVorbis:3 - Reference count: 1\n")
+        self.assertTrue(run_tests.classify_leaks(log)[0])
+
+    def test_audio_teardown_race_is_recognized(self):
+        audio_only, details = run_tests.classify_leaks(self.AUDIO)
+        self.assertTrue(audio_only)
+        self.assertEqual(len(details), 3)
+
+    def test_any_other_leak_is_not_tolerated(self):
+        audio_only, details = run_tests.classify_leaks(self.AUDIO + "Leaked instance: Node3D:9 - Node path:\n")
+        self.assertFalse(audio_only)
+        self.assertIn("leaked: Node3D", details)
+        texture = "Resource still in use: res://a.png (CompressedTexture2D)\n"
+        self.assertFalse(run_tests.classify_leaks(self.AUDIO + texture)[0])
+
+    def test_a_leak_without_detail_is_not_tolerated(self):
+        self.assertEqual(run_tests.classify_leaks("WARNING: 3 ObjectDB instances were leaked at exit\n"), (False, []))
+
+    def test_an_rid_leak_beside_the_audio_race_is_not_tolerated(self):
+        rid = "ERROR: 2 RID allocations of type 'N12MeshStorage4MeshE' were leaked at exit."
+        audio_only, details = run_tests.classify_leaks(self.AUDIO + rid + "\n")
+        self.assertFalse(audio_only)
+        self.assertIn(rid, details)
+
+
+class RunSuite(unittest.TestCase):
+    """run_suite() turns only the audio-teardown race into a note; every other leak still fails."""
+    SUMMARY = ("WARNING: 3 ObjectDB instances were leaked at exit (run with `--verbose` for details).\n"
+               "ERROR: 1 resources still in use at exit (run with --verbose for details).\n")
+    RID = "ERROR: 2 RID allocations of type 'N12MeshStorage4MeshE' were leaked at exit."
+
+    def run_with_log(self, log):
+        result = run_tests.Result("fake", 1.0, 0, run_tests.find_problems(log, 0, []), log)
+        with mock.patch.object(run_tests, "run_once", return_value=result):
+            return run_tests.run_suite("godot", "fake", [])
+
+    def test_the_audio_race_alone_passes_with_a_note(self):
+        result = self.run_with_log(self.SUMMARY + ClassifyLeaks.AUDIO)
+        self.assertTrue(result.passed, result.problems)
+        self.assertIn("audio-teardown race", result.notes[0])
+
+    def test_an_rid_leak_mixed_with_the_audio_race_still_fails(self):
+        result = self.run_with_log(self.SUMMARY + self.RID + "\n" + ClassifyLeaks.AUDIO)
+        self.assertFalse(result.passed)
+        self.assertIn(self.RID, result.problems)
+        self.assertEqual(result.notes, [])
+
+
+class SetupFailures(unittest.TestCase):
+    """A run that stops before any suite still writes a results summary saying why."""
+
+    def run_main(self, results, **patches):
+        argv = ["run_tests.py", "--godot", "godot", "-k", "runner_logic", "--results", str(results)]
+        with mock.patch("sys.argv", argv), contextlib.redirect_stderr(io.StringIO()), \
+                contextlib.ExitStack() as stack:
+            for name, value in patches.items():
+                stack.enter_context(mock.patch.object(run_tests, name, value))
+            return run_tests.main()
+
+    def test_an_isolation_failure_writes_the_summary(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            results = Path(tmp, "summary.json")
+            code = self.run_main(results, check_isolation=mock.Mock(return_value="user:// resolved to /real"))
+            self.assertEqual(code, 2)
+            summary = json.loads(results.read_text(encoding="utf-8"))
+            self.assertIn("/real", summary["setup_error"])
+            self.assertEqual(summary["suites"], [])
+
+    def test_a_probe_that_cannot_start_is_an_isolation_failure(self):
+        with mock.patch.object(run_tests.subprocess, "run", side_effect=FileNotFoundError("no godot")):
+            self.assertIn("no godot", run_tests.check_isolation("missing-godot"))
+        timeout = subprocess.TimeoutExpired(["godot"], 120)
+        with mock.patch.object(run_tests.subprocess, "run", side_effect=timeout):
+            self.assertIn("timed out", run_tests.check_isolation("godot"))
+
+    def test_an_import_timeout_writes_the_summary(self):
+        timeout = subprocess.TimeoutExpired(["godot", "--import"], run_tests.TIMEOUT)
+        with tempfile.TemporaryDirectory() as tmp, \
+                mock.patch.object(run_tests.subprocess, "run", side_effect=timeout):
+            results = Path(tmp, "summary.json")
+            code = self.run_main(results, check_isolation=mock.Mock(return_value=None))
+            self.assertEqual(code, 1)
+            summary = json.loads(results.read_text(encoding="utf-8"))
+            self.assertIn("timed out", summary["setup_error"])
+
+    def test_an_import_failure_writes_the_summary(self):
+        imported = subprocess.CompletedProcess([], 0, stdout="ERROR: Cannot import x.png\n", stderr="")
+        with tempfile.TemporaryDirectory() as tmp, \
+                mock.patch.object(run_tests.subprocess, "run", return_value=imported):
+            results = Path(tmp, "summary.json")
+            code = self.run_main(results, check_isolation=mock.Mock(return_value=None))
+            self.assertEqual(code, 1)
+            summary = json.loads(results.read_text(encoding="utf-8"))
+            self.assertIn("Cannot import x.png", summary["setup_error"])
+
+
+class LoadConfig(unittest.TestCase):
+    def test_unknown_suites_and_missing_reasons_are_errors(self):
+        text = ('[skip]\nghost = "gone"\nreal = " "\n[serial]\nspecter = "timing"\nreal = ""\n'
+                '[expected_errors]\nphantom = ["x"]\n')
+        self.assertEqual(len(run_tests.load_config(["real"], text).errors), 5)
+
+    def test_committed_config_matches_the_suites_on_disk(self):
+        self.assertEqual(run_tests.load_config(run_tests.discover()).errors, [])
+
+
+class Discover(unittest.TestCase):
+    def test_finds_top_level_and_nested_suites_but_not_helpers(self):
+        suites = run_tests.discover()
+        self.assertIn("runner_logic", suites)
+        self.assertIn("assets/a1_check", suites)
+        self.assertNotIn("support/armed_measure", suites)  # extends RefCounted: a helper, not a suite
+
+
+if __name__ == "__main__":
+    unittest.main()