Severity: minor
Tags: patch

Running the test ‘mailcap-parsing-and-mailcap-mime-info’ will set the
HOME environment variable to a temporary directory.  After the test the
directory is removed (thanks to the ‘ert-with-temp-directory’ macro),
but the value of the environment variable not restored, polluting the
state of a running Emacs and affecting later commands in the Emacs
session, like the vc-* commands when git cannot find its global
configuration anymore.

The patch wraps the test in a ‘let’ and ‘unwind-protect’ to restore the
value of the environment variable after the test has been run.