Test reexcution

FlowLiveDataConversionTest.kt

@Test
fun testReexecution() = runBlockingTest {
  val source = MutableStateFlow(1)
  val liveData = source.flatMapConcat {
    flowOf(it, it * 10) // Could be actual network request
  }.asLiveData()
  val observer = object : Observer<Int> {
    var observeHistory = mutableListOf<Int>()
    override fun onChanged(t: Int) {
      observeHistory.add(t)
    }
  }
  // User navigates to the current page
  liveData.observeForever(observer)
  // User leaves the page
  liveData.removeObserver(observer)
  assertEquals(listOf(1, 10), observer.observeHistory)
  // User comes back to the page after 5 seconds
  testDispatcher.advanceTimeBy(5001L)
  liveData.observeForever(observer)
  liveData.removeObserver(observer)
  assertEquals(listOf(1, 10, 1, 10), observer.observeHistory)
  // Clean up
  testDispatcher.advanceUntilIdle()
}