Async Testing ‐ Testing normal functions that launch a coroutine

Scenario

• Most of the time we come across scenarios where the system under test(SUT) is a normal function.
• But this normal function launches a new co-routine and performs some action in an async way.
• If the function was a suspend function, We could have used a run-blocking way to test it on the test case so the test case does not finish until the suspend function finishes the execution.
• This is more common where a view calls a function in a view-model and the view-model launches a co-routine.
• Since the launched co-routine is independent we will not be able to use a run-blocking function.

Errors Faced

when we do not use the test dispatcher during the unit test

ERROR OBSERVED:-> Module with the Main dispatcher had failed to initialize. For tests Dispatchers.setMain from kotlinx-coroutines-test module can be used ERROR OBSERVED:-> The coroutines are to be run on main-dispatcher, But the point to note here is that the main-dispatcher is associated with main-thread-looper, The main thread is associated with an android device and the this is not available when unit tests are run , So we face this error