diff --git a/.gitignore b/.gitignore
index 2ac512d..8d37e36 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,4 +10,7 @@ dist/
 .pytest_cache/
 .mypy_cache/
 # Jupyter Notebook checkpoints
-.ipynb_checkpoints/
\ No newline at end of file
+.ipynb_checkpoints/
+# Test coverage artifacts
+.coverage
+htmlcov/
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index dae7963..0000000
--- a/setup.cfg
+++ /dev/null
@@ -1,18 +0,0 @@
-[flake8]
-max-line-length = 100
-extend-ignore = E203, W503
-
-[isort]
-profile = black
-line_length = 100
-known_first_party = simicpipeline
-
-[tool:pytest]
-testpaths = tests
-addopts = -q
-
-[mypy]
-python_version = 3.9
-ignore_missing_imports = True
-strict_optional = True
-warn_unused_ignores = True
diff --git a/src/simicpipeline/__init__.py b/src/simicpipeline/__init__.py
index 65c8dd7..989885e 100644
--- a/src/simicpipeline/__init__.py
+++ b/src/simicpipeline/__init__.py
@@ -18,7 +18,7 @@
 
 try:
     from simicpipeline.core.aucprocessor import AUCProcessor
-    __all__.append("AUProcessor")
+    __all__.append("AUCProcessor")
 except ImportError as e:
     import warnings
     warnings.warn(f"Could not import AUCprocessor: {e}")
diff --git a/src/simicpipeline/_jupyter.py b/src/simicpipeline/_jupyter.py
index fb75025..df318c2 100644
--- a/src/simicpipeline/_jupyter.py
+++ b/src/simicpipeline/_jupyter.py
@@ -1,5 +1,4 @@
 # src/simicpipeline/_jupyter.py
-import os
 import subprocess
 
 def jupyter():
diff --git a/src/simicpipeline/core/__init__.py b/src/simicpipeline/core/__init__.py
index e0a1034..00925ac 100644
--- a/src/simicpipeline/core/__init__.py
+++ b/src/simicpipeline/core/__init__.py
@@ -2,12 +2,7 @@
 Core functionality for SimiC Pipeline
 """
 
-# This module is part of simicpipeline.core
-# All imports are handled at the package level (simicpipeline.__init__.py)
-# Individual modules can be imported as:
 from simicpipeline.core.base import SimiCBase
+
 __all__ = ["SimiCBase"]
-#   from simicpipeline.core.simicvisualization import SimiCVisualization
-#   from simicpipeline.core.simicpreprocess import MagicPipeline, ExperimentSetup
-#   from simicpipeline.core.aucprocessor import AUCprocessor
 
diff --git a/src/simicpipeline/core/aucprocessor.py b/src/simicpipeline/core/aucprocessor.py
index 869e84c..c35a46e 100644
--- a/src/simicpipeline/core/aucprocessor.py
+++ b/src/simicpipeline/core/aucprocessor.py
@@ -14,32 +14,6 @@
 from simicpipeline.core import SimiCBase
 from typing import Optional, Union
 
-# class BaseProcessor(SimiCBase):
-#     """
-#     Base class for SimiC processors.
-#     Provides common functionality for file handling and data loading.
-#     """
-
-
-#     def __init__(self, p2df, p2res):
-#         """
-#         Initialize the base processor.
-        
-#         Args:
-#             p2df (str): Path to dataframe pickle file
-#             p2res (str): Path to results pickle file
-#         """
-#         self.p2df = Path(p2df)
-#         self.p2res = Path(p2res)
-#         self.validate_files()
-    
-#     def validate_files(self):
-#         """Validate that required files exist."""
-#         if not self.p2df.exists():
-#             raise FileNotFoundError(f"Data file not found: {self.p2df}")
-#         if not self.p2res.exists():
-#             raise FileNotFoundError(f"Results file not found: {self.p2res}")
-
 
 class AUCProcessor(SimiCBase):
     """
diff --git a/src/simicpipeline/core/simicpreprocess.py b/src/simicpipeline/core/simicpreprocess.py
index c6150ab..07e1d99 100644
--- a/src/simicpipeline/core/simicpreprocess.py
+++ b/src/simicpipeline/core/simicpreprocess.py
@@ -18,31 +18,6 @@
 
 from simicpipeline.core import SimiCBase
 
-# class SimiCPreprocess(SimiCBase):
-#     """
-#     Base preprocessing pipeline for SimiC analysis.
-#     Provides common utilities for both MAGIC imputation and experiment setup.
-#     """
-
-#     def __init__(self, 
-#                  project_dir: Union[str, Path],
-#                  ):
-#         """
-#         Initialize base preprocessing pipeline.
-
-#         Args:
-#             project_dir: Directory for project files
-#         """
-#         super().__init__(project_dir = project_dir)
-    
-#     def _create_directory_structure(self) -> None:
-#         """Create standard SimiC directory structure."""
-       
-#         self.input_files_dir = self.input_path
-#         self.output_simic_dir = self.output_path
-#         self.figures_dir = self.figures_path
-#         self.matrices_dir = self.matrices_path
-
 
 class MagicPipeline(SimiCBase):
     """
diff --git a/src/simicpipeline/data/__init__.py b/src/simicpipeline/data/__init__.py
index e69de29..754fc4a 100644
--- a/src/simicpipeline/data/__init__.py
+++ b/src/simicpipeline/data/__init__.py
@@ -0,0 +1,3 @@
+"""Data files bundled with SimiCPipeline."""
+
+__all__: list[str] = []
diff --git a/src/simicpipeline/utils/__init__.py b/src/simicpipeline/utils/__init__.py
index 82ef492..f560c86 100644
--- a/src/simicpipeline/utils/__init__.py
+++ b/src/simicpipeline/utils/__init__.py
@@ -4,16 +4,14 @@
     load_from_matrix_market,
     load_from_anndata,
     write_pickle,
-    install_package,
     format_time,
-    print_tree
+    print_tree,
 )
 
 __all__ = [
     "load_from_matrix_market",
     "load_from_anndata",
     "write_pickle",
-    "install_package",
     "format_time",
-    "print_tree"
+    "print_tree",
 ]
\ No newline at end of file
diff --git a/src/simicpipeline/utils/io.py b/src/simicpipeline/utils/io.py
index fd37f98..a2b3c2d 100644
--- a/src/simicpipeline/utils/io.py
+++ b/src/simicpipeline/utils/io.py
@@ -1,19 +1,15 @@
 from __future__ import annotations
-from typing import Optional, Tuple, Union
+from typing import Optional, Union
 from pathlib import Path
 import pickle
 import pandas as pd
-import numpy as np
-from scipy.sparse import coo_matrix
-# Install packages
 
-def install_package(package_name):
-   """Install a package using pip3."""
-   import subprocess
-   import sys
-   subprocess.check_call([sys.executable, "-m", "pip", "install", package_name])
 
-# Directories
+def _install_package(package_name: str) -> None:
+    """Install a package using pip (internal utility, not part of public API)."""
+    import subprocess
+    import sys
+    subprocess.check_call([sys.executable, "-m", "pip", "install", package_name])
 
 
 def print_tree(directory: Union[str,Path] = Path('.'),
@@ -40,7 +36,7 @@ def print_tree(directory: Union[str,Path] = Path('.'),
         │   └── utils/
         │       └── io.py
     """
-        #  Print the root directory name at the top
+    # Print the root directory name at the top
     directory = Path(directory)
     if current_depth == 0:
         print(f"{directory.name}/")
@@ -62,7 +58,7 @@ def print_tree(directory: Union[str,Path] = Path('.'),
             extension = "    " if is_last else "│   "
             print_tree(item, prefix + extension, max_depth, current_depth + 1)
 
-# Loaders
+
 def load_from_anndata(
     path: Union[str, Path],
 ) -> object:
@@ -83,15 +79,15 @@ def load_from_anndata(
 
     path = Path(path)
     adata = ad.read_h5ad(str(path))
-    if adata.raw == None:
+    if adata.raw is None:
         print("No raw attribute found in AnnData object.")
         
     return adata
 
 def load_from_matrix_market(
     matrix_path: Union[str, Path],
-    genes_path: Union[str, Path] = None,
-    cells_path: Union[str, Path] = None,
+    genes_path: Optional[Union[str, Path]] = None,
+    cells_path: Optional[Union[str, Path]] = None,
     transpose: bool = False,
     cells_index_name: str = "Cell",
 ) -> object:
@@ -127,9 +123,9 @@ def load_from_matrix_market(
     # Load names
     genes = None
     cells = None
-    if genes_path and genes_path.exists():
+    if genes_path is not None and Path(genes_path).exists():
         genes = pd.read_csv(genes_path, header=None, sep="\t").iloc[:, 0].astype(str).tolist()
-    if cells_path and cells_path.exists():
+    if cells_path is not None and Path(cells_path).exists():
         cells = pd.read_csv(cells_path, header=None, sep="\t").iloc[:, 0].astype(str).tolist()
 
     # Convert to dense for simplicity; adjust if large matrices are expected
@@ -150,7 +146,7 @@ def load_from_matrix_market(
 
     return df
 
-# Writers
+
 def write_pickle(obj, file_path):
     file_path = Path(file_path)
     file_path.parent.mkdir(parents=True, exist_ok=True)
@@ -164,7 +160,6 @@ def write_pickle(obj, file_path):
         print(f"Pickle failed with error: {e}")
 
 
-@staticmethod
 def format_time(seconds: float) -> str:
     """
     Format time duration in human-readable format.
@@ -185,5 +180,3 @@ def format_time(seconds: float) -> str:
         return f"{minutes}min {secs}s"
     else:
         return f"{secs}s"
-
-###########################################################################################
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_core_base.py b/tests/test_core_base.py
new file mode 100644
index 0000000..670c5f9
--- /dev/null
+++ b/tests/test_core_base.py
@@ -0,0 +1,48 @@
+"""Smoke tests for core base class."""
+
+from pathlib import Path
+
+import pytest
+
+from simicpipeline.core.base import SimiCBase, _load_assignment_file
+
+
+class TestSimiCBase:
+    """Smoke tests for SimiCBase initialization and helpers."""
+
+    def test_creates_project_dir(self, tmp_path):
+        project_dir = tmp_path / "my_project"
+        assert not project_dir.exists()
+        base = SimiCBase(project_dir)
+        assert project_dir.exists()
+        assert base.project_dir == project_dir
+
+    def test_existing_project_dir(self, tmp_path):
+        base = SimiCBase(tmp_path)
+        assert base.project_dir == tmp_path
+
+    def test_format_time_delegates(self, tmp_path):
+        base = SimiCBase(tmp_path)
+        assert base.format_time(60) == "1min 0s"
+
+    def test_print_project_info(self, tmp_path, capsys):
+        base = SimiCBase(tmp_path)
+        base.print_project_info(max_depth=1)
+        captured = capsys.readouterr()
+        assert tmp_path.name in captured.out
+
+
+class TestLoadAssignmentFile:
+    """Tests for _load_assignment_file helper."""
+
+    def test_new_csv_format(self, tmp_path):
+        csv_file = tmp_path / "assignment.csv"
+        csv_file.write_text("category,label\ncell1,0\ncell2,1\ncell3,0\n")
+        labels = _load_assignment_file(csv_file)
+        assert list(labels) == [0, 1, 0]
+
+    def test_legacy_format(self, tmp_path):
+        tsv_file = tmp_path / "assignment.txt"
+        tsv_file.write_text("0\n1\n1\n0\n")
+        labels = _load_assignment_file(tsv_file)
+        assert list(labels) == [0, 1, 1, 0]
diff --git a/tests/test_utils_io.py b/tests/test_utils_io.py
new file mode 100644
index 0000000..078e0c4
--- /dev/null
+++ b/tests/test_utils_io.py
@@ -0,0 +1,59 @@
+"""Tests for simicpipeline.utils.io utilities."""
+
+import pickle
+from pathlib import Path
+
+import pytest
+
+from simicpipeline.utils.io import format_time, print_tree, write_pickle
+
+
+class TestFormatTime:
+    """Tests for the format_time utility function."""
+
+    def test_seconds_only(self):
+        assert format_time(45) == "45s"
+
+    def test_minutes_and_seconds(self):
+        assert format_time(90) == "1min 30s"
+
+    def test_hours_minutes_seconds(self):
+        assert format_time(3661) == "1h 1min 1s"
+
+    def test_zero(self):
+        assert format_time(0) == "0s"
+
+    def test_returns_string(self):
+        assert isinstance(format_time(100), str)
+
+
+class TestWritePickle:
+    """Tests for the write_pickle utility function."""
+
+    def test_writes_and_reloads(self, tmp_path):
+        obj = {"key": [1, 2, 3]}
+        out = tmp_path / "test.pkl"
+        write_pickle(obj, out)
+        assert out.exists()
+        with open(out, "rb") as f:
+            loaded = pickle.load(f)
+        assert loaded == obj
+
+    def test_creates_parent_directories(self, tmp_path):
+        obj = "hello"
+        out = tmp_path / "nested" / "dir" / "test.pkl"
+        write_pickle(obj, out)
+        assert out.exists()
+
+
+class TestPrintTree:
+    """Tests for the print_tree utility function."""
+
+    def test_runs_without_error(self, tmp_path, capsys):
+        (tmp_path / "a.txt").write_text("x")
+        sub = tmp_path / "sub"
+        sub.mkdir()
+        (sub / "b.txt").write_text("y")
+        print_tree(tmp_path, max_depth=2)
+        captured = capsys.readouterr()
+        assert tmp_path.name in captured.out