test: Add better tests for TSClient

[Dhaiwat10]

Is your feature request related to a problem? Please describe.
At the moment, there is only one really really basic test case covering the TSClient. There are no test cases covering the actual inner working.

Describe the solution you'd like
More test cases that cover the inner working of TSClient.

Describe alternatives you've considered
No test cases. Not cool.

Happy to work on this issue myself. 😄

[jsjoeio]

^I second this. We need this! I didn't manage to get anything beyond the really really basic test case but wanted to at least get the ball rolling 🤣