Add commented tests.

packages/expo-av/android/build.gradle

@@ -72,6 +72,11 @@ if (new File(rootProject.projectDir.parentFile, 'package.json').exists()) {
 }
 
 dependencies {
+//  implementation 'org.junit.jupiter:junit-jupiter-api:5.5.1'
+//  runtimeOnly "org.junit.jupiter:junit-jupiter-engine:5.5.1"
+//
+//  implementation 'io.mockk:mockk:1.9'
+
   unimodule "unimodules-core"
   unimodule "unimodules-permissions-interface"
   // Newer version introduces dependency versions conflict

packages/expo-av/android/src/test/java/expo/modules/av/progress/ProgressLooperTest.kt

@@ -0,0 +1,222 @@
+//package expo.modules.av.progress
+//
+//import io.mockk.Runs
+//import io.mockk.every
+//import io.mockk.just
+//import io.mockk.mockk
+//import io.mockk.spyk
+//import io.mockk.verify
+//import org.junit.jupiter.api.BeforeEach
+//import org.junit.jupiter.api.Test
+//
+//internal class ProgressLooperTest {
+//
+//  interface TestTimeMachine : TimeMachine {
+//    fun advanceBy(interval: Long)
+//    fun triggerListeners(by: Long = Long.MAX_VALUE)
+//  }
+//
+//  object TimeMachineInstance : TestTimeMachine {
+//
+//    override var time = 0L
+//
+//    var callbacks: Map<TimeMachineTick, Long> = HashMap()
+//
+//    override fun advanceBy(interval: Long) {
+//      time += interval
+//    }
+//
+//    override fun triggerListeners(by: Long) {
+//      val toInvoke = callbacks.filter { it.value < by }
+//      callbacks = callbacks.filter { it.value >= by }
+//      toInvoke.forEach {
+//        it.key()
+//      }
+//    }
+//
+//    override fun scheduleAt(intervalMillis: Long, callback: TimeMachineTick) {
+//      if (intervalMillis > 0) {
+//        callbacks = callbacks.plus(callback to time + intervalMillis)
+//      }
+//    }
+//
+//    fun reset() {
+//      callbacks = HashMap()
+//      time = 0
+//    }
+//  }
+//
+//  lateinit var looper: ProgressLooper
+//  lateinit var callback: TimeMachineTick
+//  lateinit var timeMachine: TestTimeMachine
+//
+//  @BeforeEach
+//  fun setUp() {
+//    TimeMachineInstance.reset()
+//    timeMachine = spyk(TimeMachineInstance)
+//    looper = ProgressLooper(timeMachine)
+//    callback = mockk()
+//    every { callback() } just Runs
+//  }
+//
+//  @Test
+//  fun `callback not invoked prematurely`() {
+//    looper.loop(1000, callback)
+//    verify(exactly = 0) { callback() }
+//  }
+//
+//  @Test
+//  fun `callback invoked once after time passed`() {
+//    looper.loop(1000L, callback)
+//    timeMachine.advanceBy(1000L)
+//    timeMachine.triggerListeners()
+//    verify(exactly = 1) { callback() }
+//  }
+//
+//  @Test
+//  fun `callback invoked twice after two timeouts`() {
+//    looper.loop(1000, callback)
+//    timeMachine.advanceBy(1100)
+//    timeMachine.triggerListeners()
+//    timeMachine.advanceBy(1100)
+//    timeMachine.triggerListeners()
+//    verify(exactly = 2) { callback() }
+//  }
+//
+//  @Test
+//  fun `callback invoked once after twice too big timeout`() {
+//    looper.loop(1000, callback)
+//    timeMachine.advanceBy(2200)
+//    timeMachine.triggerListeners(2200)
+//    verify(exactly = 1) { callback() }
+//  }
+//
+//  @Test
+//  fun `callback not invoked after looping stopped`() {
+//    looper.loop(1000L, callback)
+//    timeMachine.advanceBy(1001)
+//    timeMachine.triggerListeners()
+//    verify(exactly = 1) { callback() }
+//    looper.stopLooping()
+//    timeMachine.advanceBy(1001)
+//    timeMachine.triggerListeners()
+//    verify(exactly = 1) { callback() }
+//  }
+//
+//  @Test
+//  fun `callback not invoked earlier if interval shortened`() {
+//    looper.loop(1000L, callback)
+//
+//    looper.loop(100, callback)
+//    timeMachine.advanceBy(110)
+//    timeMachine.triggerListeners(110)
+//    verify(exactly = 0) { callback() }
+//
+//    timeMachine.advanceBy(900)
+//    timeMachine.triggerListeners(1010)
+//    verify(exactly = 1) { callback() }
+//
+//    timeMachine.advanceBy(100)
+//    timeMachine.triggerListeners(1110)
+//    verify(exactly = 2) { callback() }
+//  }
+//
+//  @Test
+//  fun `callback invoked earlier even if interval lengthened`() {
+//    looper.loop(1000, callback)
+//
+//    looper.loop(2000, callback)
+//    timeMachine.advanceBy(1100)
+//    timeMachine.triggerListeners(1100)
+//
+//    verify(exactly = 1) { callback() }
+//  }
+//
+//  @Test
+//  fun `callback not invoked later even if interval lengthened`() {
+//    looper.loop(1000, callback)
+//
+//    looper.loop(2000, callback)
+//    timeMachine.advanceBy(1110)
+//    timeMachine.triggerListeners(1100)
+//
+//    verify(exactly = 1) { callback() }
+//
+//    timeMachine.advanceBy(1110)
+//    timeMachine.triggerListeners(2200)
+//
+//    verify(exactly = 1) { callback() }
+//  }
+//
+//  @Test
+//  fun `next tick scheduled with adjustment to passed time when invoked too late`() {
+//    looper.loop(1000L, callback)
+//
+//    timeMachine.advanceBy(1100)
+//    timeMachine.triggerListeners(1100)
+//
+//    verify(exactly = 1) { timeMachine.scheduleAt(900, any()) }
+//  }
+//
+//  @Test
+//  fun `next tick scheduled with adjustment to passed time when invoked too early`() {
+//    looper.loop(1000L, callback)
+//
+//    timeMachine.advanceBy(900)
+//    timeMachine.triggerListeners()
+//
+//    verify(exactly = 1) { timeMachine.scheduleAt(1100, any()) }
+//  }
+//
+//  @Test
+//  fun `old listener not notified after new is registered`() {
+//    looper.loop(1000, callback)
+//
+//    timeMachine.advanceBy(1100)
+//    timeMachine.triggerListeners()
+//    verify(exactly = 1) { callback() }
+//
+//    looper.changeListener { }
+//    timeMachine.advanceBy(1100)
+//    timeMachine.triggerListeners()
+//
+//    verify(exactly = 1) { callback() }
+//  }
+//
+//  @Test
+//  fun `new listener is notified after registration`() {
+//    looper.loop(1000) { }
+//
+//    timeMachine.advanceBy(1100)
+//    timeMachine.triggerListeners()
+//    looper.changeListener(callback)
+//    timeMachine.advanceBy(1100)
+//    timeMachine.triggerListeners()
+//
+//    verify(exactly = 1) { callback() }
+//  }
+//
+//  @Test
+//  fun `time machine not called if no looping started`() {
+//    timeMachine.advanceBy(1100)
+//    timeMachine.triggerListeners()
+//
+//    verify(exactly = 0) { timeMachine.scheduleAt(any(), any()) }
+//  }
+//
+//  @Test
+//  fun `time machine not called after looping stopped`() {
+//    looper.loop(1000) {}
+//    verify(exactly = 1) { timeMachine.scheduleAt(any(), any()) }
+//
+//    timeMachine.advanceBy(1100)
+//    timeMachine.triggerListeners()
+//    verify(exactly = 2) { timeMachine.scheduleAt(any(), any()) }
+//
+//    looper.stopLooping()
+//    timeMachine.advanceBy(100000)
+//    timeMachine.triggerListeners()
+//    verify(exactly = 2) { timeMachine.scheduleAt(any(), any()) }
+//  }
+//
+//}