# Python Pytest Creator Skill > Generate comprehensive pytest test files for Python using the test-generator-framework Use when this capability is needed. - Skill: `tomevault-io/python-pytest-creator-skill` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/python-pytest-creator-skill` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/python-pytest-creator-skill/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/python-pytest-creator-skill --- ## What I do I implement a complete Python pytest test generation workflow by extending the `test-generator-framework`: 1. **Analyze Python Codebase**: Scan Python application to identify functions, classes, and modules 2. **Detect Python Testing Setup**: Identify pytest version and Poetry availability 3. **Generate Python-Specific Scenarios**: Create comprehensive test scenarios covering: - Happy paths, edge cases, and error handling - Python-specific patterns (decorators, context managers, async functions) 4. **Delegate to Framework**: Use `test-generator-framework` for core test generation workflow 5. **Ensure Executability**: Verify tests run with `poetry run pytest` or `pytest` ## When to use me Use this workflow when: - You need to create comprehensive pytest test files for a Python application - You want to ensure all edge cases and error conditions are covered - You need tests that integrate with Poetry environments - You prefer a systematic approach to test generation with user confirmation - You want to ensure tests run correctly with your project's pytest version **Framework**: This skill extends `test-generator-framework` for core test generation workflow, adding Python-specific functionality. ## Prerequisites - Python project with Poetry (`pyproject.toml`) or pip (`requirements.txt`) - Pytest installed and configured in project - Python source code to test - Appropriate file permissions to create test files Note: Poetry is optional. If Poetry is installed and `pyproject.toml` exists, tests will use `poetry run pytest`. Otherwise, tests will use `pytest` directly. ## Steps ### Step 1: Analyze Python Codebase - Use glob patterns to find Python files: `**/*.py` - Exclude test files: `**/test_*.py`, `**/*_test.py`, `**/tests/**/*.py` - Read each Python file to identify: - Functions: `def function_name(parameters):` - Classes: `class ClassName:` - Methods: `def method_name(self, parameters):` - Async functions: `async def async_function():` - Decorators: `@decorator_name` - Context managers: `with context_manager():` - Identify import statements to understand dependencies ### Step 2: Detect Python Testing Setup - Check for `pyproject.toml` or `requirements.txt` - Determine pytest version and plugins - Check for Poetry installation: `poetry --version` ### Step 3: Generate Python-Specific Test Scenarios #### Function Scenarios (Python-specific) - **Happy Path**: Normal inputs with expected outputs - **Edge Cases**: Empty strings, empty lists, `None`, `0`, `-1` - **Error Cases**: Invalid types, out of range values, missing parameters - **Python Features**: Decorators, type hints, default arguments, *args/**kwargs #### Class Scenarios - **Initialization**: `__init__` with valid/invalid parameters - **Method Behavior**: Public/private method testing - **Special Methods**: `__str__`, `__repr__`, `__eq__`, `__hash__` - **Class Methods**: `@classmethod`, `@staticmethod` - **Property**: Properties defined with `@property` - **Context Managers**: `__enter__` and `__exit__` methods #### Async Function Scenarios - **Awaitable Results**: Normal async execution - **Concurrency**: Multiple async calls with asyncio.gather() - **Error Handling**: Async exceptions with pytest.raises() - **Timeout**: Tests that should timeout ### Step 4: Delegate to Test Generator Framework **Note**: Core test generation workflow is provided by `test-generator-framework`. This skill focuses only on Python-specific aspects. Refer to `test-generator-framework` for: - Generic test file creation structure - Framework detection and command determination - User confirmation workflow - Executability verification Python-specific test file templates below extend the framework structure. ### Step 5: Create Test Files (Python-specific) ```python """ Test suite for .py Generated by python-pytest-creator skill """ import pytest from import , @pytest.fixture def sample_instance(): """Create a sample instance for testing""" return ClassName(param1, param2) def test_function_name_happy_path(sample_instance): """Test that function_name works with valid inputs""" result = function_name(valid_input) assert result == expected_output def test_function_name_edge_case_empty(): """Test that function_name handles empty input""" result = function_name("") assert result is None def test_function_name_error_invalid_type(): """Test that function_name raises ValueError for invalid type""" with pytest.raises(ValueError): function_name(invalid_input) @pytest.mark.parametrize("input,expected", [ (1, "one"), (2, "two"), ]) def test_function_name_parametrized(input, expected): """Test function_name with multiple inputs""" result = function_name(input) assert result == expected class TestClassName: """Test suite for ClassName""" def test_initialization(self): """Test that ClassName initializes correctly""" instance = ClassName(param1, param2) assert instance.attribute == expected_value def test_method_behavior(self, sample_instance): """Test that ClassName.method_name works correctly""" result = sample_instance.method_name(param) assert result == expected_result @pytest.mark.asyncio async def test_async_function_happy_path(): """Test successful async execution""" result = await async_function(valid_input) assert result["status"] == "success" ``` ### Step 6: Verify Executability Refer to `test-generator-framework` for core executability verification. ### Step 7: Display Summary ``` ✅ Python test files created successfully! **Test Files Created:** - tests/test_.py ( tests) **Total Tests Generated:** **Test Framework:** Pytest **Python-Specific Categories:** - Decorator tests: - Context manager tests: - Special method tests: - Async function tests: ``` **To run tests:** ```bash # If Poetry is installed: poetry run pytest tests/test_.py -v poetry run pytest --cov= tests/ # Otherwise: pytest tests/test_.py -v pytest --cov= tests/ ``` ## Python-Specific Scenario Generation Python-specific patterns to focus on: ### Decorator Testing - **Decorator Execution**: Decorator modifies function behavior correctly - **Decorator Chaining**: Multiple decorators apply correctly - **Decorator Arguments**: Decorator with parameters works - **Class Decorators**: Decorator classes properly ### Context Manager Testing - **`__enter__`**: Returns context manager correctly - **`__exit__`**: Cleans up resources properly - **Exception Handling**: Exceptions in context are handled - **Nested Context**: Multiple context managers work together ### Special Method Testing - **`__str__`**: String representation is correct - **`__repr__`**: Developer representation is correct - **`__eq__`**: Equality comparison works - **`__hash__`**: Hash allows use in sets/dicts - **`__len__`**: Length function returns correct value - **`__getitem__`**: Item access works - **`__setitem__`**: Item assignment works ### Property Testing - **Getter**: Property returns correct value - **Setter**: Property sets value correctly - **Deleter**: Property deletion works - **Cached Properties**: Cached behavior is correct ## Best Practices Refer to `test-generator-framework` for general best practices. Python-specific best practices: - **Pytest Features**: Use fixtures, parametrization, marks - **Async Testing**: Use pytest-asyncio for async functions - **Type Hints**: Include type hints for better test coverage - **Mocking**: Use pytest-mock or unittest.mock appropriately - **Integration Tests**: Always include at least one integration test with real database sessions — mock-only tests mask session boundary bugs ## Common Issues Refer to `test-generator-framework` for general issues. Python-specific issues: ### Poetry Not Installed **Issue**: `poetry run pytest` command not found **Solution**: Use `pytest` directly instead: ```bash pytest tests/ ``` ### pytest-asyncio Not Installed **Issue**: Async tests fail or don't run **Solution**: Install pytest-asyncio: ```bash poetry add --group dev pytest-asyncio # or pip install pytest-asyncio ``` ### Module Not Found **Issue**: Import errors for modules to test **Solution**: Add source to PYTHONPATH: ```bash export PYTHONPATH="${PYTHONPATH}:$(pwd)" ``` ### MagicMock Truthy Headers **Issue**: `MagicMock` for `response.headers` creates truthy auto-created mocks, causing false positives in header-checking code. ```python # WRONG — MagicMock auto-creates `response.headers.get()` as truthy mock_response = MagicMock() mock_response.headers.get.return_value = "Bearer test-token" assert mock_response.headers.get("Authorization") == "Bearer test-token" # passes # But also: mock_response.headers.get("X-Missing") returns a MagicMock (truthy!) # CORRECT — use a real dict for headers mock_response = MagicMock() mock_response.headers = {"Authorization": "Bearer test-token"} # real dict assert mock_response.headers.get("Authorization") == "Bearer test-token" assert mock_response.headers.get("X-Missing") is None # correctly returns None ``` ### Detached ORM Across Sessions (Mocking Pitfall) **Issue**: Mock-only tests mask session boundary bugs. When an ORM object is fetched in one session and mutated in another, mocks won't catch the detached state. ```python # WRONG — mock hides the bug: test passes but production fails mock_session = MagicMock() mock_session.get.return_value = User(id="u1", name="old") repo = UserRepository(mock_session) repo.update_name("u1", "new") mock_session.commit.assert_called_once() # passes, but nothing actually flushed # CORRECT — include at least one integration test with real sessions @pytest.mark.asyncio async def test_update_user_real_session(test_db_session): user = User(id="u1", name="old") test_db_session.add(user) await test_db_session.commit() # fetch and update in the SAME session fetched = await test_db_session.get(User, "u1") fetched.name = "new" await test_db_session.commit() result = await test_db_session.get(User, "u1") assert result.name == "new" ``` ## Troubleshooting Checklist Refer to `test-generator-framework` for general checklist. Python-specific additions: Before generating tests: - [ ] Python files exist and are syntactically correct - [ ] `pyproject.toml` or `requirements.txt` exists - [ ] Pytest is installed - [ ] Poetry is installed (if using Poetry) ## Related Commands ```bash # Poetry commands poetry run pytest -v poetry run pytest --cov= tests/ poetry install --group dev pytest-asyncio # Direct pytest commands pytest -v pytest tests/test_module.py -v pytest --cov= tests/ pytest -k "test_name" # Python commands python -m pytest export PYTHONPATH="${PYTHONPATH}:$(pwd)" ``` --- > Source: [darellchua2/opencode-config-template](https://github.com/darellchua2/opencode-config-template) — distributed by [TomeVault](https://tomevault.io).