How to use `pytest` from Python?

Question

I'm working in a project that recently switched to the pytest unittest framework. I was used to calling my tests from Eclipse, so that I can use the debugger (e.g. placing breakpoints to analyze how a test failure develops). Now this is no longer possible, since the only way to run the tests is via the command line blackbox.

Is there some way to use pytest from within Python, so that one is not forced to drop out of the IDE? The tests should of course not be run in a separate process.

Answer 1

I think I can now answer my own question, it's pretty simple:

import pytest

pytest.main(args)

which is documented in the Section "Calling pytest from Python code". Then I can run this module and/or start it with the integrated debugger.

args is the list of command-line arguments, so for example to run only particular tests I can use something like:

args_str = "-k test_myfavorite"
args = args_str.split(" ")
pytest.main(args)

Answer 2

It seems that now (py.test version 2.0+) someone can also do this :

import pytest

pytest.main('-x {0}'.format(argument))

# Or
# pytest.main(['-x', 'argument'])

Ref

Answer 3

This is now supported by pytest and described nicely in the documentation.

You can invoke pytest from Python code directly:

import pytest
pytest.main()

this acts as if you would call “pytest” from the command line. It will not raise SystemExit but return the exitcode instead. You can pass in options and arguments:

pytest.main(["-x", "mytestdir"])

Answer 4

For me it was this:

pytest.main(["-x", "path to test file", "args"])

For example:

import pytest
pytest.main(["-x", "/api/test", "-vv"])

Answer 5

Maybe you could give a try to pycharm it has direct integration with py.test (I use it at work) and debugger runs perfectly.

Answer 6

I have not tried with eclipse, but as was suggested in a related question, it is possible to use the --pdb command line option with py.test. Maybe it is possible to configure eclipse that way.

However, calling the standard import pdb;pdb.set_trace() will not directly call the debugger. First it will issue an error which in turn will activate the debugger. This might or might not make things work differently.

Answer 7

You can just run py.test --pdb if you just want to a debugger and don't need the IDE