Testing

Testing Standards

Framework

• Use pytest for all tests
• Target 80%+ code coverage

File Organization

• Tests in tests/ directory mirroring src/ structure
• Test files: test_<module>.py or <module>_test.py
• Test functions: test_<description>

Fixtures

• Use fixtures for reusable test data
• Prefer scope="function" unless shared state is needed
• Use conftest.py for shared fixtures

Example:

import pytest

@pytest.fixture
def sample_user():
    """Create a sample user for testing."""
    return User(name="Test User", email="test@example.com")

def test_user_creation(sample_user):
    assert sample_user.name == "Test User"
    assert sample_user.email == "test@example.com"

Parametrization

• Use @pytest.mark.parametrize for testing multiple inputs
• Keep parameter names descriptive

Example:

@pytest.mark.parametrize("input_val,expected", [
    (1, 2),
    (2, 4),
    (0, 0),
])
def test_double(input_val, expected):
    assert double(input_val) == expected

Assertions

• Use plain assert statements
• Write clear assertion messages for complex checks
• Test one concept per test function

Mocking

• Use pytest-mock or unittest.mock
• Mock external dependencies (APIs, databases)
• Avoid mocking the code under test

Commands

• Run tests: pytest
• With coverage: pytest --cov
• Verbose: pytest -v
• Single file: pytest tests/test_specific.py
• Single test: pytest tests/test_specific.py::test_name