Update testsuite for Generator, simplify service provider and mock

[barryvdh]

Summary

I think the models were not typehinted because of Lumen etc. Now that we've bumped versions, we can skip Lumen.

Also simplified the serviceprovider and the mock a bit, to allow for testing the Generator.

The Filesystem mock only mock the Put method now, rest is not mocked (partial mock).

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Misc. change (internal, infrastructure, maintenance, etc.)

Checklist

• Existing tests have been adapted and/or new tests have been added
• Update the README.md
• Code style has been fixed via composer fix-style

[barryvdh]

Ah yes, of course the actual file is different based on the PHP version, which makes it a bit difficult I guess 🤔