create-tests

name	create-tests
description	Generate pytest tests for Python code. Use when asked to write, add or scaffold tests for a function, class or module. Covers happy path, edge cases, exceptions and parametrize patterns.
argument-hint	Source file or function to test

Create Tests

Generates idiomatic pytest test files for Python source code.

When to Use

• Writing tests for a new function or class.
• Adding missing coverage to an existing module.
• Scaffolding a test file from scratch.

Procedure

1. Read the target source file to understand the public API and types.
2. Check tests/ for existing conftest.py, fixtures, and naming patterns.
3. Consult pytest patterns reference for idiomatic examples.
4. Determine test file path: mirror source under tests/
   • src/pkg/module.py → tests/pkg/test_module.py
5. Write tests covering:
   • Happy path (expected inputs/outputs)
   • Edge cases (empty, boundary, large values)
   • Error scenarios (pytest.raises with match=)
   • Multiple inputs (pytest.mark.parametrize)
6. Mock all external dependencies (HTTP, DB, file I/O) with unittest.mock (stdlib) or pytest-mock if already available.
7. Report what was created and any coverage gaps.

Requirements

• Type-annotate all test functions: -> None.
• Each test has a one-line docstring.
• Test names follow test_<function>_<scenario>.
• No repeated setup code — use fixtures or parametrize.