How do I debug py.test in PyCharm when coverage is enabled?
Coverage is enabled using --cov=project --cov-report=term-missing, removing this and breakpoints are hit.
Versions: pycharm 5.0.3, pytest==2.8.5, pytest-cache==1.0, pytest-cov==2.2.0, pytest-pep8==1.0.6, pytest-xdist==1.13.1, python-coveralls==2.6.0.
(thanks for jon's advice on further diagnosing the issue)
There is now a flag in py.test to disable coverage which you can activate when running tests from PyCharm.
The flag to use is --no-cov. If you want this to apply to all your test runs you can add this to the default pytest configuration as below:
Extra tip: You probably also want a -s flag in there so output isn't swallowed by py.test. See https://stackoverflow.com/a/17810324/238166 for details.
In case you receive an "unrecognized argument" error, you may need to install pytest-cov, e.g. by pip install pytest-cov.
来源：https://stackoverflow.com/questions/34870962/how-to-debug-py-test-in-pycharm-when-coverage-is-enabled