add unit test coverage and tests!

[rawlingsj]

When the slack bot was made open source it came with no tests from its original source and so is very hard to make changes, understand what is meant to happen or what may be incorrect.

We should add test coverage and unit / integration tests, at the time of creating this issue we've started to add some but there is a long way to go. Not sure when we can say this issue can be closed, maybe once we get 50% coverage or something?

[jenkins-x-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.
If this issue is safe to close now please do so with /close.
Provide feedback via https://jenkins-x.io/community.
/lifecycle stale

[rawlingsj]

/remove-lifecycle stale

[jenkins-x-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.
If this issue is safe to close now please do so with /close.
Provide feedback via https://jenkins-x.io/community.
/lifecycle stale

[jenkins-x-bot]

Stale issues rot after 30d of inactivity.
Mark the issue as fresh with /remove-lifecycle rotten.
Rotten issues close after an additional 30d of inactivity.
If this issue is safe to close now please do so with /close.
Provide feedback via https://jenkins-x.io/community.
/lifecycle rotten