### Question:
ViewGroupCompat { public static boolean isTransitionGroup(@NonNull ViewGroup group) { if (Build.VERSION.SDK_INT >= 21) { return group.isTransitionGroup(); } Boolean explicit = (Boolean) group.getTag(R.id.tag_transition_group); return (explicit != null && explicit) || group.getBackground() != null || ViewCompat.getTransitionName(group) != null; } private  ViewGroupCompat(); @Deprecated static boolean onRequestSendAccessibilityEvent(ViewGroup group, View child,
            AccessibilityEvent event); @Deprecated static void setMotionEventSplittingEnabled(ViewGroup group, boolean split); static int getLayoutMode(@NonNull ViewGroup group); static void setLayoutMode(@NonNull ViewGroup group, int mode); static void setTransitionGroup(@NonNull ViewGroup group, boolean isTransitionGroup); static boolean isTransitionGroup(@NonNull ViewGroup group); @ScrollAxis @SuppressWarnings("RedundantCast") // Intentionally invoking interface method. static int getNestedScrollAxes(@NonNull ViewGroup group); static final int LAYOUT_MODE_CLIP_BOUNDS; static final int LAYOUT_MODE_OPTICAL_BOUNDS; }### Answer:
@Test public void isTransitionGroup() { assertFalse(ViewGroupCompat.isTransitionGroup(mViewGroup)); InstrumentationRegistry.getInstrumentation().runOnMainSync(new Runnable() { @Override public void run() { ViewCompat.setBackground(mViewGroup, new ColorDrawable(Color.GRAY)); } }); assertTrue(ViewGroupCompat.isTransitionGroup(mViewGroup)); }