Moved most tests in 'test_clerk' into a class.
Moved most tests in 'test_clerk' into a class.

daviddeng/azrael,olitheolix/azrael,olitheolix/azrael,daviddeng/azrael,olitheolix/azrael,olitheolix/azrael,daviddeng/azrael,daviddeng/azrael,daviddeng/azrael,olitheolix/azrael