Update some comments but more important, I added the test for GridCell and put in the correct matcher (there is not #must_not_have_selector).
Also, very important, and there may be a better way to do this, but GridCell#classes was modifying the class attribute, so I created a copy of the array before manipulating it. I suppose if this is the best way, it could be copied only when necessary (when adding the .end class).
Update some comments but more important, I added the test for GridCell and put in the correct matcher (there is not #must_not_have_selector).
Also, very important, and there may be a better way to do this, but GridCell#classes was modifying the class attribute, so I created a copy of the array before manipulating it. I suppose if this is the best way, it could be copied only when necessary (when adding the .end class).