Fix test to check pause button visibility

[anandwana001]

Describe the bug
Espresso doesn't test anything when the app is in the idle state. Testing Audio becomes difficult in such cases.

Expected behavior
Propose a solution to test the pause icon visiblity while playing audio
Cases we need to test:

• Pause icon is visible when audio is playing
• All the test should pass on Espresso
• All the test should pass on Robolectric

Additional context
Tests that needs to be fixed from ExplorationActivityTest and AudioFragmentTest

[These two in ExplorationActivityTest were fixed in #5245]

fun testAudioWithWifi_openRatioExploration_clickAudioIcon_checkAudioFragmentHasDefaultLanguageAndAutoPlays()

fun testAudioWithWifi_openRatioExploration_continueToInteraction_clickAudioButton_submitAnswer_checkFeedbackAudioPlays()

[Tests Pending fixes]

fun testAudioFragment_invokePrepared_clickPlayButton_showsPauseButton()

fun testAudioFragment_invokePrepared_clickPlay_touchSeekBar_checkStillPlaying()

#2216 (comment)

[MaskedCarrot]

@anandwana001 may I work on this? Also can you please give me a few pointers on how to get started?

[anandwana001]

@MaskedCarrot We need to create a fake audio library so that we can test cases when the espresso test is idle like pause icon is only visible when espresso test is idle, but we need something using which we can fake our media player that audio is playing and the pause icon gets visible.

[MaskedCarrot]

@anandwana001 I tried reading about this online but I could not find any resource of much help. Can you please guide me on this?

[anandwana001]

Basically, there is no third party lib todo this, but we need to create the whole thing here.

[MaskedCarrot]

@anandwana001 I am facing a few difficulties on this may we connect on giiter regarding this issue?

[anandwana001]

Sure

[srikanthkb]

I took a look at this issue for the first test case testAudioWithWifi_openRatioExploration_clickAudioIcon_checkAudioFragmentHasDefaultLanguageAndAutoPlays(), here's what I think:

• When the audio player button is clicked, the audio player UI is loaded and it immediately starts playing the audio. The audio player plays the audio on the main thread, which blocks the testCoroutineDispatchers resource (because we registered idling resource in setUp()). This makes Espresso wait for the resource R.drawable.ic_pause_circle_filled_white_24dp in line 549(which is supposedly blocked):
  

  oppia-android/app/src/sharedTest/java/org/oppia/android/app/player/exploration/ExplorationActivityTest.kt

  Lines 540 to 549 in 6107ecd

  	waitForTheView(withText("What is a Ratio?"))
  	onView(withId(R.id.action_audio_player)).perform(click())
  	onView(
  	allOf(
  	withId(R.id.play_pause_audio_icon),
  	withEffectiveVisibility(Visibility.VISIBLE)
  	)
  	)
  	onView(allOf(withId(R.id.audio_language_icon), withEffectiveVisibility(Visibility.VISIBLE)))
  	waitForTheView(withDrawable(R.drawable.ic_pause_circle_filled_white_24dp))

Interestingly, if we call testCoroutineDispatchers.unregisterIdlingResource() before the execution of this particular test, the test is successfully passed only on Espresso (not Roboelectric). I think this does not allow blocking of the resource, forcing the test to be asynchronous and allows Espresso access to the R.drawable.ic_pause_circle_filled_white_24dp resource.

[srikanthkb]

On more deeper investigation, I found that there are two issues with this test:

1. In the following line
   

   oppia-android/app/src/sharedTest/java/org/oppia/android/app/player/exploration/ExplorationActivityTest.kt

   Line 549 in 6107ecd

   waitForTheView(withDrawable(R.drawable.ic_pause_circle_filled_white_24dp))

   
   The error observed is as follows:
   

2. If the above line was commented out (for debugging purpose), the test would still fail on the following statement:
   

   oppia-android/app/src/sharedTest/java/org/oppia/android/app/player/exploration/ExplorationActivityTest.kt

   Lines 550 to 556 in 6107ecd

   	onView(withId(R.id.play_pause_audio_icon)).check(
   	matches(
   	withDrawable(
   	R.drawable.ic_pause_circle_filled_white_24dp
   	)
   	)
   	)

   
   The error observed for this statement is as follow:
   

[pravesh00]

@anandwana001 Can I work on this issue?

[anandwana001]

@pravesh00 Before assigning, have you check the above comments?
Also, I suggest commenting on what approach you will use to solve this issue before sending out the PR.
Comment 1 - #2480 (comment)
Comment 2 - #2480 (comment)