Massage text input for difflib when comparing pformat output of
different line lengths.
Also do not strip ndiff output on the left, which currently already
removes indenting for lines with no differences.
Before:
E AssertionError: assert ['version', '...version_info'] == ['version', '...version', ...]
E Right contains 3 more items, first extra item: ' '
E Full diff:
E - ['version', 'version_info', 'sys.version', 'sys.version_info']
E + ['version',
E + 'version_info',
E + 'sys.version',
E + 'sys.version_info',
E + ' ',
E + 'sys.version',
E + 'sys.version_info']
After:
E AssertionError: assert ['version', '...version_info'] == ['version', '...version', ...]
E Right contains 3 more items, first extra item: ' '
E Full diff:
E [
E 'version',
E 'version_info',
E 'sys.version',
E 'sys.version_info',
E + ' ',
E + 'sys.version',
E + 'sys.version_info',
E ]