[Tests] Get to 100% code coverage.

[davidfstr]

It's just work...

--- Important
9: Edge cases when parsing referer and URLs. --> 2%
1: Add "Delete" endpoint tests after the existing "Refresh" endpoint tests.

--- Remainder
2: Address missing resources.
3: Non-quiet.
2: Argument parsing errors (for domain).

[davidfstr]

Strategy: Increase minimum required coverage % by 2% on each release.