Question 1

How to test a custom mypy plugin with pytest-mypy-plugins?

Accepted Answer

Use the YAML spec to define test cases with the plugin imported, set MYPYPATH in the env section to point to your plugin, and run pytest. The README shows examples with environment variables for simulating import paths.

Question 2

pytest-mypy-plugins vs writing mypy tests in Python – which is better?

Accepted Answer

pytest-mypy-plugins is better for structured, YAML-based testing integrated with pytest, while writing tests in Python offers more flexibility and debugability. Choose based on team preference and need for automation.

Question 3

How do I set up environment variables for mypy tests in YAML?

Accepted Answer

Add an 'env' key in your YAML test case with variables like PYTHONPATH, as shown in the README. This allows simulating different paths without modifying the system environment.

Question 4

Can pytest-mypy-plugins be used with Django type stubs?

Accepted Answer

Yes, it's commonly used for testing Django type stubs; examples in the repository include Django-related tests. You can define files and env vars to mimic Django project structures.

Question 5

What are the performance implications of using pytest-mypy-plugins?

Accepted Answer

Running mypy in a subprocess adds overhead, and using --mypy-same-process can cause import cache issues. It's best for CI/CD where isolated runs are acceptable, but may slow down local testing.

Question 6

How to handle relative paths in pytest-mypy-plugins tests?

Accepted Answer

Convert relative paths to absolute ones using tools like $(pwd) in shell commands or set --mypy-same-process flag, as advised in the README to avoid temporary directory issues.

pytest-mypy-plugins

What is pytest-mypy-plugins?

Overview

Use Cases

Best For

Found a gem we're missing?

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions