git.cmd.Git.execute(..): fix `with_stdout=False` by ngie-eign · Pull Request #2126 · gitpython-developers/GitPython

In the event the end-user called one of the APIs with
`with_stdout=False`, i.e., they didn't want to capture stdout, the code
would crash with an AttributeError or ValueError when trying to
dereference the stdout/stderr streams attached to `Popen(..)` objects.

Be more defensive by checking the streams first to make sure they're not
`None` before trying to access their corresponding attributes.

Add myself to AUTHORS and add corresponding regression tests for the
change.

Signed-off-by: Enji Cooper <yaneurabeya@gmail.com>

Prior to this the test would fail [silently] on my macOS host during the
test and then pytest would complain loudly about it being an issue
post-session (regardless of whether or not the test was being run).

Squash the unwritable directory to mute noise complaints from pytest.

Signed-off-by: Enji Cooper <yaneurabeya@gmail.com>