Step clock animation: Fix NPE when startValues or endValues are null

By looking at parent class implementations of Transition, it seems that
is a legit case, and that should be handled by returning a null Animator

Test: SplitShadeTransitionAdapterTest.kt
Fixes: 274002399
Change-Id: I07501eb4bbd001bdb6014a3644e41cd8b575ccee
diff --git a/packages/SystemUI/src/com/android/systemui/shade/NotificationPanelViewController.java b/packages/SystemUI/src/com/android/systemui/shade/NotificationPanelViewController.java
index ff523ad..c2738b2 100644
--- a/packages/SystemUI/src/com/android/systemui/shade/NotificationPanelViewController.java
+++ b/packages/SystemUI/src/com/android/systemui/shade/NotificationPanelViewController.java
@@ -5004,9 +5004,13 @@
             captureValues(transitionValues);
         }
 
+        @Nullable
         @Override
-        public Animator createAnimator(ViewGroup sceneRoot, TransitionValues startValues,
-                TransitionValues endValues) {
+        public Animator createAnimator(ViewGroup sceneRoot, @Nullable TransitionValues startValues,
+                @Nullable TransitionValues endValues) {
+            if (startValues == null || endValues == null) {
+                return null;
+            }
             ValueAnimator anim = ValueAnimator.ofFloat(0, 1);
 
             Rect from = (Rect) startValues.values.get(PROP_BOUNDS);
diff --git a/packages/SystemUI/tests/src/com/android/systemui/shade/SplitShadeTransitionAdapterTest.kt b/packages/SystemUI/tests/src/com/android/systemui/shade/SplitShadeTransitionAdapterTest.kt
new file mode 100644
index 0000000..64fec5b
--- /dev/null
+++ b/packages/SystemUI/tests/src/com/android/systemui/shade/SplitShadeTransitionAdapterTest.kt
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.systemui.shade
+
+import android.animation.Animator
+import android.testing.AndroidTestingRunner
+import android.transition.TransitionValues
+import androidx.test.filters.SmallTest
+import com.android.keyguard.KeyguardStatusViewController
+import com.android.systemui.SysuiTestCase
+import com.android.systemui.shade.NotificationPanelViewController.SplitShadeTransitionAdapter
+import com.google.common.truth.Truth.assertThat
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.Mock
+import org.mockito.MockitoAnnotations
+
+@SmallTest
+@RunWith(AndroidTestingRunner::class)
+class SplitShadeTransitionAdapterTest : SysuiTestCase() {
+
+    @Mock private lateinit var keyguardStatusViewController: KeyguardStatusViewController
+
+    private lateinit var adapter: SplitShadeTransitionAdapter
+
+    @Before
+    fun setUp() {
+        MockitoAnnotations.initMocks(this)
+        adapter = SplitShadeTransitionAdapter(keyguardStatusViewController)
+    }
+
+    @Test
+    fun createAnimator_nullStartValues_returnsNull() {
+        val animator = adapter.createAnimator(startValues = null, endValues = TransitionValues())
+
+        assertThat(animator).isNull()
+    }
+
+    @Test
+    fun createAnimator_nullEndValues_returnsNull() {
+        val animator = adapter.createAnimator(startValues = TransitionValues(), endValues = null)
+
+        assertThat(animator).isNull()
+    }
+
+    @Test
+    fun createAnimator_nonNullStartAndEndValues_returnsAnimator() {
+        val animator =
+            adapter.createAnimator(startValues = TransitionValues(), endValues = TransitionValues())
+
+        assertThat(animator).isNotNull()
+    }
+}
+
+private fun SplitShadeTransitionAdapter.createAnimator(
+    startValues: TransitionValues?,
+    endValues: TransitionValues?
+): Animator? {
+    return createAnimator(/* sceneRoot= */ null, startValues, endValues)
+}