diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..c99c4a1
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,187 @@
+"""Pytest configuration and fixtures."""
+
+import tempfile
+from pathlib import Path
+import pytest
+
+
+@pytest.fixture
+def sample_python_file(tmp_path):
+    """Create a sample Python file for testing."""
+    content = '''"""Sample module for testing stubgen."""
+
+def greet(name: str) -> str:
+    """Greet a person by name.
+    
+    Args:
+        name: The name to greet
+    
+    Returns:
+        The greeting message
+    """
+    return f"Hello, {name}"
+
+
+class Calculator:
+    """A simple calculator class."""
+    
+    def __init__(self, initial_value: int = 0):
+        self.value = initial_value
+    
+    def add(self, x: int, y: int) -> int:
+        """Add two numbers."""
+        return self.value + x + y
+    
+    def multiply(self, x: int, y: int = 2) -> int:
+        """Multiply numbers."""
+        return self.value * x * y
+
+
+def process_list(items: list[str], count: int = 10) -> list[str]:
+    """Process items from a list.
+    
+    Args:
+        items: List of strings to process
+        count: Number of items
+    
+    Returns:
+        Processed list
+    """
+    return items[:count]
+
+
+def get_user_info(name: str, age: int = 25, active: bool = True) -> dict:
+    """Get user information.
+    
+    Args:
+        name: User's name
+        age: User's age
+        active: Whether user is active
+    
+    Returns:
+        User info dictionary
+    """
+    return {"name": name, "age": age, "active": active}
+
+
+async def async_fetch(url: str, timeout: int = 30) -> str:
+    """Fetch data from URL asynchronously.
+    
+    Args:
+        url: URL to fetch
+        timeout: Request timeout in seconds
+    
+    Returns:
+        Response content
+    """
+    return f"Content from {url}"
+
+
+class DataProcessor:
+    """Data processing class."""
+    
+    def __init__(self, config: dict):
+        self.config = config
+        self.processed = 0
+    
+    def process(self, data: list[dict]) -> list[dict]:
+        """Process data items.
+        
+        Args:
+            data: List of data dictionaries
+        
+        Returns:
+            Processed data
+        """
+        self.processed = len(data)
+        return data
+    
+    def reset(self):
+        """Reset processor state."""
+        self.processed = 0
+'''
+    file_path = tmp_path / "sample.py"
+    file_path.write_text(content)
+    return file_path
+
+
+@pytest.fixture
+def sample_directory(tmp_path):
+    """Create a directory with multiple Python files."""
+    module1 = tmp_path / "module1.py"
+    module1.write_text('''"""Module 1."""
+
+def func1(x: int) -> int:
+    return x * 2
+
+def func2(y: str) -> str:
+    return y.upper()
+''')
+    
+    module2 = tmp_path / "module2.py"
+    module2.write_text('''"""Module 2."""
+
+class MyClass:
+    def method(self, value: float) -> float:
+        return value / 2
+''')
+    
+    subdir = tmp_path / "subpackage"
+    subdir.mkdir()
+    subdir_file = subdir / "submodule.py"
+    subdir_file.write_text('''"""Submodule."""
+
+def sub_func() -> bool:
+    return True
+''')
+    
+    return tmp_path
+
+
+@pytest.fixture
+def untyped_python_file(tmp_path):
+    """Create a Python file without type annotations."""
+    content = '''"""Module without type annotations."""
+
+def greet(name):
+    return f"Hello, {name}"
+
+def add(a, b):
+    return a + b
+
+class Calculator:
+    def __init__(self, initial=0):
+        self.value = initial
+    
+    def add(self, x, y):
+        return self.value + x + y
+'''
+    file_path = tmp_path / "untyped.py"
+    file_path.write_text(content)
+    return file_path
+
+
+@pytest.fixture
+def mixed_file(tmp_path):
+    """Create a file with mixed typed and untyped code."""
+    content = '''"""Mixed typed and untyped code."""
+
+def typed_func(x: int, y: str) -> list[str]:
+    return [str(x), y]
+
+def untyped_func(a, b):
+    return a * b
+
+class MixedClass:
+    typed_attr: int = 10
+    untyped_attr = "hello"
+    
+    def typed_method(self, x: int) -> int:
+        return x * 2
+    
+    def untyped_method(self, x):
+        return x
+'''
+    file_path = tmp_path / "mixed.py"
+    file_path.write_text(content)
+    return file_path