alijilani-dev/claude/pytest-python

Claude Code and agent skill by alijilani-dev/claude

Trust tier 3
  • community
Source check pending

Checking that the SKILL.md file is still in the repository.

Comprehensive pytest testing skill for Python projects. Write efficient, maintainable tests with fixtures, parametrization, markers, mocking, and assertions. Use when: (1) Writing new tests for Python code, (2) Setting up pytest in a project, (3) Creating fixtures for test dependencies, (4) Parametrizing tests for multiple inputs, (5) Mocking/patching with monkeypatch, (6) Debugging test failures, (7) Organizing test suites with markers, (8) Any Python testing task.

Install

npx vskill@latest install alijilani-dev/claude/pytest-python

SKILL.md

Pytest Testing for Python

Quick Reference

Test Discovery

Pytest auto-discovers tests matching:

  • Files: test_*.py or *_test.py
  • Functions: test_* prefix
  • Classes: Test* prefix (no __init__)
Running Tests
bash
pytest                           # Run all tests
pytest test_mod.py               # Single module
pytest tests/                    # Directory
pytest -k "name"                 # By keyword
pytest -m slow                   # By marker
pytest test_mod.py::test_func    # Specific test
pytest --durations=10            # Show slowest tests

Fixtures

Fixtures provide reusable test dependencies.

Basic Fixture
python
import pytest
@pytest.fixture
def sample_data():
    return {"key": "value"}
def test_example(sample_data):
    assert sample_data["key"] == "value"
Fixture Scopes
python
@pytest.fixture(scope="function")  # Default: per test
@pytest.fixture(scope="class")     # Per test class
@pytest.fixture(scope="module")    # Per module
@pytest.fixture(scope="session")   # Entire session
Fixture with Teardown (yield)
python
@pytest.fixture
def db_connection():
    conn = create_connection()
    yield conn
    conn.close()  # Cleanup after test
Factory Fixture
python
@pytest.fixture
def make_user():
    def _make_user(name, role="user"):
        return {"name": name, "role": role}
    return _make_user
def test_users(make_user):
    admin = make_user("Alice", role="admin")
    user = make_user("Bob")
Parametrized Fixture
python
@pytest.fixture(params=["mysql", "postgres", "sqlite"])
def database(request):
    return create_db(request.param)

Parametrization

Run tests with multiple inputs.

python
@pytest.mark.parametrize("input,expected", [
    (1, 2),
    (2, 4),
    (3, 6),
])
def test_double(input, expected):
    assert input * 2 == expected
Multiple Parameters (Combinations)
python
@pytest.mark.parametrize("x", [1, 2])
@pytest.mark.parametrize("y", [10, 20])
def test_multiply(x, y):  # Runs 4 combinations
    assert x * y > 0
With Expected Failures
python
@pytest.mark.parametrize("input,expected", [
    (1, 1),
    pytest.param(0, 1, marks=pytest.mark.xfail),
])
def test_factorial(input, expected):
    assert factorial(input) == expected

Markers

Built-in Markers
python
@pytest.mark.skip(reason="Not implemented")
def test_feature(): ...
@pytest.mark.skipif(sys.platform == "win32", reason="Unix only")
def test_unix(): ...
@pytest.mark.xfail(reason="Known bug")
def test_buggy(): ...
Custom Markers

Register in pytest.ini or pyproject.toml:

ini
[pytest]
markers =
    slow: marks tests as slow
    integration: integration tests
python
@pytest.mark.slow
def test_slow_operation(): ...

Run: pytest -m slow or pytest -m "not slow"

Assertions

Basic Assertions
python
assert value == expected
assert value != other
assert value is None
assert value is not None
assert value in collection
assert isinstance(obj, MyClass)
Floating Point
python
assert 0.1 + 0.2 == pytest.approx(0.3)
assert result == pytest.approx(expected, rel=1e-3)
Exception Testing
python
def test_raises():
    with pytest.raises(ValueError):
        int("invalid")
def test_raises_with_match():
    with pytest.raises(ValueError, match=r"invalid.*"):
        raise ValueError("invalid input")
def test_raises_inspect():
    with pytest.raises(ValueError) as exc_info:
        raise ValueError("test error")
    assert "test" in str(exc_info.value)

Monkeypatch (Mocking)

Patching Functions
python
def test_api_call(monkeypatch):
    def mock_get(*args, **kwargs):
        return {"status": "ok"}
    monkeypatch.setattr("mymodule.api.get", mock_get)
    result = mymodule.fetch_data()
    assert result["status"] == "ok"
Environment Variables
python
def test_with_env(monkeypatch):
    monkeypatch.setenv("API_KEY", "test-key")
    assert os.environ["API_KEY"] == "test-key"
def test_without_env(monkeypatch):
    monkeypatch.delenv("API_KEY", raising=False)
Dictionary Values
python
def test_config(monkeypatch):
    monkeypatch.setitem(app.config, "DEBUG", True)

Built-in Fixtures

FixturePurpose
tmp_pathTemporary directory (pathlib.Path)
tmp_path_factorySession-scoped temp directories
capsysCapture stdout/stderr
caplogCapture log messages
monkeypatchDynamic patching
requestFixture/test metadata
Examples
python
def test_output(capsys):
    print("hello")
    captured = capsys.readouterr()
    assert captured.out == "hello\n"
def test_logging(caplog):
    import logging
    logging.warning("test warning")
    assert "test warning" in caplog.text
def test_temp_file(tmp_path):
    file = tmp_path / "test.txt"
    file.write_text("content")
    assert file.read_text() == "content"

Project Structure

Recommended layout:

project/
├── pyproject.toml
├── src/
│   └── mypackage/
│       ├── __init__.py
│       └── module.py
└── tests/
    ├── conftest.py      # Shared fixtures
    ├── test_module.py
    └── unit/
        └── test_specific.py
conftest.py

Shared fixtures available to all tests in directory:

python
# tests/conftest.py
import pytest
@pytest.fixture
def app():
    return create_app(testing=True)
@pytest.fixture
def client(app):
    return app.test_client()

Configuration

pyproject.toml
toml
[tool.pytest.ini_options]
testpaths = ["tests"]
python_files = ["test_*.py"]
python_functions = ["test_*"]
addopts = "-v --strict-markers"
markers = [
    "slow: marks tests as slow",
    "integration: integration tests",
]
filterwarnings = [
    "ignore::DeprecationWarning",
]

Best Practices

  1. One assertion focus per test - Test one behavior per function
  2. Descriptive names - test_user_creation_with_invalid_email_raises_error
  3. Use fixtures - Avoid setup duplication
  4. Isolate tests - No shared state between tests
  5. Fast unit tests - Mark slow tests with @pytest.mark.slow
  6. Parametrize - Use parametrize over copy-paste tests
  7. Test edge cases - Empty inputs, boundaries, errors

References

Security

  • Security scanPassed, 100 of 100Pattern checks on the skill's files.
  • Model reviewPassed

See the full security report

Quality evaluation

  • Task evaluationNot runNo evaluation yet. Run one in Skill Studio.

See evaluation results

Source

Popularity

7-day trend score
0

Refreshed 17 Mar 2026, 7 months ago.

Works with

Any agent vskill installs to: 56 targets in all. These 39 have a page on this site.

  • Claude Code
  • Cursor
  • GitHub Copilot
  • Windsurf
  • Codex
  • Gemini CLI
  • Cline
  • Amp
  • Roo Code
  • Goose
  • Continue
  • Kilo Code
  • Junie
  • Trae
  • OpenHands
  • Qwen Code
  • AI Agent
  • Tabnine Chat
  • Sourcegraph Cody
  • Amazon Q
  • Firebase Genkit
  • Sweep
  • Devin
  • Phind
  • Mentat
  • Claude Desktop
  • Aider
  • GPT Pilot
  • Plandex
  • bolt.new
  • v0
  • Replit Agent
  • Anse
  • TypingMind
  • BetterChatGPT
  • LibreChat
  • Warp AI
  • Pieces
  • Fig AI
Embed badge
vskill VERIFIED badge
[![vskill VERIFIED](https://verified-skill.com/api/v1/skills/alijilani-dev/claude/pytest-python/badge)](https://verified-skill.com/skills/alijilani-dev/claude/pytest-python)

Something wrong with this skill or its page? Tell us.