diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..174b7cb
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,124 @@
+"""Pytest configuration and fixtures."""
+
+import pytest
+from pathlib import Path
+import tempfile
+import os
+
+
+@pytest.fixture
+def sample_python_code():
+    """Sample Python code with various issues."""
+    return '''
+import os
+
+def dangerous_function(user_input):
+    password = "secret123"
+    result = eval(user_input)
+    cursor.execute("SELECT * FROM users WHERE name = '" + user_input + "'")
+    try:
+        do_something()
+    except:
+        pass
+    return 42 * multiplier
+
+AWS_KEY = "AKIAIOSFODNN7EXAMPLE"
+
+def process_items(items):
+    for i in range(len(items)):
+        print(items[i])
+    result = list(list(items))
+    return result
+'''
+
+
+@pytest.fixture
+def sample_javascript_code():
+    """Sample JavaScript code with various issues."""
+    return '''
+const password = "secret123";
+const AWS_KEY = "AKIAIOSFODNN7EXAMPLE";
+
+function process(userInput) {
+    const result = eval(userInput);
+    const query = "SELECT * FROM users WHERE name = " + userInput;
+    try {
+        doSomething();
+    } catch (e) {
+        // silent catch
+    }
+    for (let i = 0; i < items.length; i++) {
+        console.log(items[i]);
+    }
+}
+'''
+
+
+@pytest.fixture
+def sample_typescript_code():
+    """Sample TypeScript code with various issues."""
+    return '''
+const apiKey = "AIzaSyDxxxxxxxxxxxxxxxxxxxxxxxxxxx";
+const token = "ghp_xxxxxxxxxxxxxxxxxxxxxxxxxxxx";
+
+async function fetchData(userId: string) {
+    try {
+        const result = eval("getData(" + userId + ")");
+        return result;
+    } catch {
+        // empty catch
+    }
+}
+
+const config = {
+    password: "secret123"
+};
+'''
+
+
+@pytest.fixture
+def clean_python_code():
+    """Sample clean Python code without issues."""
+    return '''
+def calculate_total(items: list[int]) -> int:
+    """Calculate the total of all items."""
+    total = 0
+    for item in items:
+        total += item
+    return total
+
+class Calculator:
+    """A simple calculator class."""
+    
+    DEFAULT_MULTIPLIER = 1
+    
+    def __init__(self, multiplier: int = DEFAULT_MULTIPLIER):
+        self.multiplier = multiplier
+    
+    def multiply(self, value: int) -> int:
+        """Multiply the value by the multiplier."""
+        return value * self.multiplier
+'''
+
+
+@pytest.fixture
+def temp_file_with_content():
+    """Create a temporary file with given content."""
+    def _create_temp_file(content: str, suffix: str = ".py") -> Path:
+        with tempfile.NamedTemporaryFile(mode="w", suffix=suffix, delete=False) as f:
+            f.write(content)
+            return Path(f.name)
+    return _create_temp_file
+
+
+@pytest.fixture
+def temp_directory():
+    """Create a temporary directory with test files."""
+    def _create_temp_dir(files: dict[str, str]) -> Path:
+        tmpdir = tempfile.mkdtemp()
+        for filename, content in files.items():
+            filepath = Path(tmpdir) / filename
+            filepath.parent.mkdir(parents=True, exist_ok=True)
+            filepath.write_text(content)
+        return Path(tmpdir)
+    return _create_temp_dir