Add unit test coverage

[jasonblais]

[keremgocen]

Can we branch this into smaller issues for coverage on each file? I'd like to add some but it can take a bit to add coverage on everything.

[larkox]

Hi @keremgocen . The idea is not so much about adding tests to improve the coverage, but activate the coverage for this repo. You can see a similar PR here:
mattermost/mattermost-plugin-zoom#135

[keremgocen]

I'll see what I can do in the weekend then, cheers