[TESTS]: Add unit tests for all commands

[gamemaker1]

Describe the issue
No tests for any part of CLI

How could it be made better?
Add unit tests for all commands.

Screenshots
If applicable, add screenshots to help explain the benefits of your changes.

Additional context
All commands export a run function that accepts parameters. Use that to test it. A provision must be added for defining a test configuration too, since commands directly access the configuration file while running