test-revert: add methodical revert with explicit file path
We now also test reverting file to the working directory parent
content. However this differs from the previously introduced test by using
the explicit path of each "case file" when calling revert. This should
result in the same result regarding file content and backup creation,
but the output of the `hg revert` call should differ.
try:
import coverage
getattr(coverage, 'process_startup', lambda: None)()
except ImportError:
pass