Unable to debug in pycharm with pytest

For my situation, I found what the problem is:

If there is --cov in pytest.ini, then breakpoints in pycharm won't work, after deleting all --cov in pytest.ini, the breakpoints in pycharm can work.

Reason:

"The coverage module and pycharm's debugger use the same tracing api (sys.settrace) - they don't work together. " -- https://github.com/pytest-dev/pytest-cov/issues/131

References:

How to debug py.test in PyCharm when coverage is enabled

The root issue is debugging does not work if you have coverage enabled by default (usually on pytest.ini).

To disable just on pycharm, just add --no-cov on the Additional Arguments on the Run/Debug Configurations.
Update Templates -> Python tests -> pytest, so every new test gets this configuration.
After this, delete your current debug settings and redebug it.

Pycharm 2018.3.x (still works in 2020.x)