Tests: Dependencies

[rxaviers]

On #370, we had missing dependencies. But, we were unable to figure that out by our current unit tests. They are indirect dependencies (i.e., "plugin dependencies") and another parallel unit test was loading them before they were being used. Therefore, no problem occurred until we started to test them on high latency envs like via browserstack-runner.

Ideally, each unit test should be executed using the dependencies it's explicitly requiring with no interference.