python ยท diff
git:20260318.4d14ab2 to git:20260318.b5f0c27
27 added, 6 removed. Audit A to A.
---
name: python
description: Write clean, readable Pythonic code. Use this skill any time you write or change a Python file.
---
+ # General guidelines
+
+
# Coding Style
- Always write clean, readable, well separated, well organized, Pythonic code.
- Don't run linters or formatters, they will run automatically after every edit by the harness.
+ - Always write clean, readable, well separated, well organized, Pythonic code.
+ - Don't run linters or formatters, they will run automatically after every edit by the harness.
+ - When using `datetime`, import it like this: `import datetime as dt`
# Type hints
- ALWAYS type hint every function and method signature precisely even in tests.
- "" -> None" return values are not necessary, they are just noise.
- No need to type hint variables from functions call return values inside function bodies, they are inferred from the method return type,
except extreme cases when the type is a huge help or a generic and it's concrete type cannot be determined.
+ - Only use APIs, class names, variables or objects which you already read or
+ know exist for sure.
+ - Use the new pipe operator for `Optional` variables like this: `value | None`
+
# Testing
- - NEVER use mocks, never assert on method calls, just use real objects and assert on results. When absolutely necessary and can't be avoided,
- use `pytest.monkeypatch`, but that should be rare when the setup would be too different or the code have side effects, but in that case,
- consider writing a fake instead of using Mock or MagicMock.
- - ALWAYS assert on the full result of the function call, never just list length or containment, except where that's the point.
+ - ALWAYS use `pytest` for all tests
+ - ALWAYS assert on whole ouptut or full results in tests, not just tiny parts
+ - For mocking, use pytest `monkeypatch` fixture, NEVER `unittest.mock` and NEVER
+ any of the `Mock` classes or `patch` function
+ - IMPORTANT: NEVER import from `conftest.py`
+ - ALWAYS type hint test function parameters correctly.
+ - Don't make a test class with only one function, a module-level test function is enough
+ - NEVER use `unittest.mock` or any of the `Mock` classes or `patch` function, never assert on method calls,
+ use real objects and assert on full results. When absolutely necessary and can't be avoided, use `pytest.monkeypatch`,
+ when the test setup would be too difficult or the code have side effects, but consider writing a fake.
+ - ALWAYS assert on the full result of the function call, never just list lengths or containment, except where that's the point.
+
+
+ # Managing dependencies
+
+ - Use `uv add` for adding dependencies, never directly edit `pyproject.toml` files.
+ - For CLI scripts and apps, ALWAYS use `click` library instead of `argparse`, add it to dependencies if necessary.