Tests: Add tests that will generate more coverage

[Lilja]

Description of new feature, or changes

Adds more tests and coverage

Checklist

• [x] Your branch is up-to-date with the base branch
• [x] You've included at least one test if this is a new feature
• [ ] All tests are passing

Related Issues and Discussions

88

[Lilja]

New coverage 93%. Not sure if I can do more.

I'm changing the import is_supported() => _utils.is_supported() since it's easier to mock.