Added test case for format_suffix_patterns to validate changes introduced with issue #593.

Signed-off-by: Kevin Stone <kevinastone@gmail.com>
Tweaked some method names to be more clear and added a docstring to the test case class.

Signed-off-by: Kevin Stone <kevinastone@gmail.com>
Merge pull request #602 from kevinastone/master

TestCase for `format_suffix_patterns`