Add schema and functional tests

Nikolay Shapovalov → made their first commit to this issue’s fork.

@danflanagan8 thanks a lot for you contribution.
It would be awesome to cover code with tests.
I created MR, and test failed.
New issues to phpstan was introduced by suggested changes.
Set to NW.

MR is ready for review.

Nikolay Shapovalov → closed merge request !9

Add schema as separate commit.

@danflanagan8 thanks for your contribution.
Changes merged.

Nikolay Shapovalov → closed merge request !7

Automatically closed - issue fixed for 2 weeks with no activity.