AI Guide

Test Guide

  • Use only pytest (no unittest, no test classes).
  • All tests are top-level functions named test_*.
  • Use @pytest.fixture for setup/data.
  • Use plain assert for checks.
  • Use @pytest.mark.parametrize for multiple cases.
  • Use pytest.raises for exceptions.
  • Use tmp_path/tmpdir for temp files.
  • Each test must be independent.

Example: 

import pytest
from mymodule import myfunc

@pytest.fixture
def sample_data():
    return [1, 2, 3]

def test_myfunc_basic(sample_data):
    assert myfunc(sample_data) == expected_result

@pytest.mark.parametrize("input,expected", [(1, 2), (2, 3)])
def test_myfunc_param(input, expected):
    assert myfunc(input) == expected

def test_myfunc_error():
    with pytest.raises(ValueError):
        myfunc(bad_input)

Docstring Style Guide (PEP287 reST)

Use short, concise reST (PEP287) docstrings for all modules, classes, and functions.

Function Docstring Template

def func(arg1, arg2):
    """Short summary.

    :param int arg1: Description
    :param str arg2: Description
    :returns bool: Description
    :raises ValueError: If something goes wrong
    """

Class Docstring Template

class MyClass:
    """Short summary.

    :ivar int attr: Description
    :ivar str other: Description
    """

Module Docstring Template

"""Short summary of the module.

:var str VERSION: Module version
"""

Best Practices

  • Use a single short summary line if possible.
  • Use field lists with type on the same line as param/return (e.g., :param int foo: ...)
  • Only document what isn’t obvious from the signature.
  • Use imperative mood for descriptions.
  • Prefer single-line docstrings for trivial functions.

Examples

def add(a, b):
    """Add two numbers.

    :param float a: First number
    :param float b: Second number
    :returns float: Sum of a and b
    """

class User:
    """User object.

    :ivar str name: User name
    :ivar int age: User age
    """