Template:Asbox/testcases

Hidden unicode char
category contains hidden unicode chars, DEL and LRM (if you use Chrome, notice how the spellchecker underlines part of the word as misspelled instead of the whole word when in the editor). However, note that this is still a valid category (link for Category:Østfold geography stubs is blue, not red), so it should not be sorted under 'S' in Category:Stub message templates needing attention (though it should still be sorted under 'N' for having other non-existing cats) and that the invalid char will still be outputted to the article (and would break the pseudo-categories, but should not affect actual categories)

Missing image
If making a major revision to the template, you may remove pre tags from below to see compare how the current and sandbox versions handle missing images. Remember to pre tag again in order to avoid cluttering Category:Templates with missing files.

Missing params
=Automatic Documention= if

=Ombox messages and error sorting=

Demo article space categories only
Same as above, but this time emulating article space (note lack of error/hidden categories and ombox; also demo cats link will not show in actual article space)