MR !1735 mistakenly assumed that x.is_covered(y) means "x is covered by
y" when the opposite is true
Fix the logic of is_covered and associated tests.
Signed-off-by: Maxime Bélair <maxime.belair@canonical.com>
Known Bugs:
Will allow multiple letters in the () due to translation/unicode issues with regexing the key.
User input will probably bug out in a different locale.