2 files changed, 35 insertions, 5 deletions
diff --git a/packages/SystemUI/tests/utils/src/android/animation/AnimatorTestRule.java b/packages/SystemUI/tests/utils/src/android/animation/AnimatorTestRule.java
index 41dbc147dfc5..b820ca612bfc 100644
--- a/packages/SystemUI/tests/utils/src/android/animation/AnimatorTestRule.java
+++ b/packages/SystemUI/tests/utils/src/android/animation/AnimatorTestRule.java
@@ -68,13 +68,26 @@ public final class AnimatorTestRule implements TestRule {
 
     private final Object mLock = new Object();
     private final TestHandler mTestHandler = new TestHandler();
+    private final long mStartTime;
+    private long mTotalTimeDelta = 0;
+
+    /**
+     * Construct an AnimatorTestRule with a custom start time.
+     * @see #AnimatorTestRule()
+     */
+    public AnimatorTestRule(long startTime) {
+        mStartTime = startTime;
+    }
+
     /**
-     * initializing the start time with {@link SystemClock#uptimeMillis()} reduces the discrepancies
-     * with various internals of classes like ValueAnimator which can sometimes read that clock via
+     * Construct an AnimatorTestRule with a start time of {@link SystemClock#uptimeMillis()}.
+     * Initializing the start time with this clock reduces the discrepancies with various internals
+     * of classes like ValueAnimator which can sometimes read that clock via
      * {@link android.view.animation.AnimationUtils#currentAnimationTimeMillis()}.
      */
-    private final long mStartTime = SystemClock.uptimeMillis();
-    private long mTotalTimeDelta = 0;
+    public AnimatorTestRule() {
+        this(SystemClock.uptimeMillis());
+    }
 
     @NonNull
     @Override
diff --git a/packages/SystemUI/tests/utils/src/com/android/systemui/animation/AnimatorTestRule.kt b/packages/SystemUI/tests/utils/src/com/android/systemui/animation/AnimatorTestRule.kt
index 0ced19e3d5f3..ba9c5eda1b63 100644
--- a/packages/SystemUI/tests/utils/src/com/android/systemui/animation/AnimatorTestRule.kt
+++ b/packages/SystemUI/tests/utils/src/com/android/systemui/animation/AnimatorTestRule.kt
@@ -28,11 +28,21 @@ import org.junit.runners.model.Statement
  * advanced together.
  */
 class AnimatorTestRule : TestRule {
+    // Create the androidx rule, which initializes start time to SystemClock.uptimeMillis(),
+    // then copy that time to the platform rule so that the two clocks are in sync.
     private val androidxRule = androidx.core.animation.AnimatorTestRule()
-    private val platformRule = android.animation.AnimatorTestRule()
+    private val platformRule = android.animation.AnimatorTestRule(androidxRule.startTime)
     private val advanceAndroidXTimeBy =
         Consumer<Long> { timeDelta -> androidxRule.advanceTimeBy(timeDelta) }
 
+    /** Access the mStartTime field; bypassing the restriction of being on a looper thread. */
+    private val androidx.core.animation.AnimatorTestRule.startTime: Long
+        get() =
+            javaClass.getDeclaredField("mStartTime").let { field ->
+                field.isAccessible = true
+                field.getLong(this)
+            }
+
     /**
      * Chain is for simplicity not to force a particular order; order should not matter, because
      * each rule affects a different AnimationHandler classes, and no callbacks to code under test
@@ -55,4 +65,11 @@ class AnimatorTestRule : TestRule {
         //  animation from one to start later than the other.
         platformRule.advanceTimeBy(timeDelta, advanceAndroidXTimeBy)
     }
+
+    /**
+     * Returns the current time in milliseconds tracked by the AnimationHandlers. Note that this is
+     * a different time than the time tracked by {@link SystemClock}.
+     */
+    val currentTime: Long
+        get() = androidxRule.currentTime
 }