This was achieved by:
* moving many pass statements in tests onto their own lines, so they pass line coverage and can match an easy ignore pattern if branch coverage is added later.
* removing code that cannot be reached.
* removing long-disabled tests.
* removing unused code.
* adding tests for uncovered code
It turned out that removing `if __name__ == '__main__'` blocks that run unittest.main() at the bottom of test files was surprisingly contentious, so they remain and can be filtered out with an appropriate .coveragerc.
Return None after calling unittest.mock.patch.object.stop() regardless of whether the object was started. This makes the method idempotent.
https://bugs.python.org/issue36366
* Resolve string target to patch.dict during function call
* Add NEWS entry
* Remove unneeded call
* Restore original value for support.target and refactor assertions
* Add extra assertion to verify unpatched dict