view tests/README @ 35540:f948c5b3f5c9 stable

run-tests: avoid set PYTHONUSERBASE environment variable to None

According to python documentation, get_config_var can return None and it was
during running mercurial tests under a virtual environment with the local built
mercurial installed as a python package with `pip install -e .`.

On the other hand, if mercurial is installed in the user library folders with
`pip install --local -e .` the issue doesn't reproduce.

The fallback is that it will just set an empty string and everything should work
as before, according to https://www.python.org/dev/peps/pep-0370/:

    The path to the user base directory can be overwritten with the environment
    variable PYTHONUSERBASE. The default location is used when PYTHONUSERBASE is
    not set or empty.

To run the tests, do:

cd tests/
python run-tests.py

See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.