Coverage report generation incompatible with pytest `tmpdir` feature

Given a project structure like:

myproject
├── myproject
│   └── __init__.py
├── tests
│   └── myproject
│       └── test.py
└── setup.cfg

I’m running the command in the toplevel myproject directory:

py.test --cov=myproject --cov-report html

On stdout I can see the log output:

Coverage HTML written to dir htmlcov

However no output has been written, i.e., the myproject directory does not contain htmlcov (and neither of its subdirectories). Even a find / -name "*htmlcov*" reveals nothing.

Notes:

• The output is written if I use --cov-report html:/absolute/path/to/myproject/htmlcov.
• I get the same issue for --cov-report xml.
• My tests chdir a lot – can this mess up pytest-cov?

Versions:

• pytest: 3.8.1
• pytest-cov: 2.6.0

[tbaledent]

I also ran into the same issue recently where I couldn’t chdir into pytest’s tmpdir feature without breaking how pytest-cov locates the coverage report at the end of a test suite, so I figured I would leave a comment with a quick solution to help anyone else who might have the same problems in the future. To keep the line tmpdir.chdir() in the initdir fixture without adversely affecting any downstream tests or the coverage report generation, simply add a constant at the top of your test like OLD_DIR = os.getcwd() and then add the following to your tearDownClass (assuming you’re using the pytest fixtures within a unittest TestCase):

    @classmethod
    def tearDownClass(cls) -> None:
        # tear down some other stuff
        os.chdir(OLD_DIR)

This will cleanly revert the current working directory to the previous directory before tmpdir once the tests have completed so the coverage report can successfully be located after the test suite has completed.

[ionelmc]

We could try to make sure we dump the report in the original cwd tho (just like we handle config paths).