suspend (sus·pend, /səˈspend/) - temporarity prevent from continuing or being in force or effect

• can invoke by another suspend function or within coroutine
• it like pause and resume (not blocking thread)
• sequential function
• complie to function with callback interface Continuation<T>

public interface Continuation<in T> {
    /**
     * The context of the coroutine that corresponds to this continuation.
     */
    public val context: CoroutineContext

    /**
     * Resumes the execution of the corresponding coroutine passing a successful or failed [result] as the
     * return value of the last suspension point.
     */
    public fun resumeWith(result: Result<T>)
}

In my opinoin testing coroutine can saparate into 2 category

• Testing ViewModel
  • You have to stub TestCoroutineDispatcher into Dispatchers.setMain(dispatcher: CoroutineDispatcher) at call resetMain() after done testing
• Testing basic suspend function
  • For basic suspend function can be done the same way, if you run it on main thread.
  • For IO or other thread except main you should create coroutine context provider and stub it when testing

  interface CoroutineContextProvider {
  
      val Main: CoroutineContext
  
      val IO: CoroutineContext
  
  }