determining test coverage with py.test + gevent

Question

How can one get an accurate test coverage report when using py.test + gevent?

I've already tried the obvious thing, using the pytest-cov plugin for py.test, but it generates inaccurate reports when gevent is in use.

Answer 1

The gevent coverage issue was fixed in coveragepy recently.

However, pytest-cov fails to run with coverage>=4.

One possible fix, is to run py.test with the later versions of coverage.py without using the pytest-cov plugin.

First, install coverage >= 4 and uninstall the pytest-cov plugin:

pip install --pre --upgrade coverage
pip uninstall pytest-cov

Add the following setting to .coveragerc:

[run]
concurrency = gevent

Then run with:

coverage run -m py.test

(instead of the regular py.test run)