Fix clock fading in incorrectly

In some cases, when going from AOD->LOCKSCREEN, the isDreaming value
may still be true after the transition is started, producing a visual
flicker as the lockscreen comes up.

Don't allow DREAMING to interrupt AOD->LOCKSCREEN

Fixes: 271919264
Test: atest KeyguardTransitionScenariosTest
Test: manual test transitions for both T & U devices
Change-Id: If1028d4a98b52133790a0d97aee798c8d659ab6b

packages/SystemUI/src/com/android/systemui/keyguard/domain/interactor/FromLockscreenTransitionInteractor.kt

@@ -64,7 +64,11 @@ constructor(
                 .sample(keyguardTransitionInteractor.startedKeyguardTransitionStep, ::Pair)
                 .collect { pair ->
                     val (isAbleToDream, lastStartedTransition) = pair
-                    if (isAbleToDream && lastStartedTransition.to == KeyguardState.LOCKSCREEN) {
+                    if (
+                        isAbleToDream &&
+                            lastStartedTransition.to == KeyguardState.LOCKSCREEN &&
+                            lastStartedTransition.from != KeyguardState.AOD
+                    ) {
                         keyguardTransitionRepository.startTransition(
                             TransitionInfo(
                                 name,

packages/SystemUI/tests/src/com/android/systemui/keyguard/domain/interactor/KeyguardTransitionScenariosTest.kt

@@ -357,6 +357,50 @@ class KeyguardTransitionScenariosTest : SysuiTestCase() {
             coroutineContext.cancelChildren()
         }
 
+    @Test
+    fun `LOCKSCREEN to DREAMING`() =
+        testScope.runTest {
+            // GIVEN a device that is not dreaming or dozing
+            keyguardRepository.setDreamingWithOverlay(false)
+            keyguardRepository.setWakefulnessModel(startingToWake())
+            keyguardRepository.setDozeTransitionModel(
+                DozeTransitionModel(from = DozeStateModel.DOZE, to = DozeStateModel.FINISH)
+            )
+            runCurrent()
+
+            // GIVEN a prior transition has run to LOCKSCREEN
+            runner.startTransition(
+                testScope,
+                TransitionInfo(
+                    ownerName = "",
+                    from = KeyguardState.GONE,
+                    to = KeyguardState.LOCKSCREEN,
+                    animator =
+                        ValueAnimator().apply {
+                            duration = 10
+                            interpolator = Interpolators.LINEAR
+                        },
+                )
+            )
+            reset(mockTransitionRepository)
+
+            // WHEN the device begins to dream
+            keyguardRepository.setDreamingWithOverlay(true)
+            advanceUntilIdle()
+
+            val info =
+                withArgCaptor<TransitionInfo> {
+                    verify(mockTransitionRepository).startTransition(capture(), anyBoolean())
+                }
+            // THEN a transition to DREAMING should occur
+            assertThat(info.ownerName).isEqualTo("FromLockscreenTransitionInteractor")
+            assertThat(info.from).isEqualTo(KeyguardState.LOCKSCREEN)
+            assertThat(info.to).isEqualTo(KeyguardState.DREAMING)
+            assertThat(info.animator).isNotNull()
+
+            coroutineContext.cancelChildren()
+        }
+
     @Test
     fun `LOCKSCREEN to DOZING`() =
         testScope.runTest {