### Question:
WorkConstraintsTracker implements ConstraintController.OnConstraintUpdatedCallback { public void replace(@NonNull List<WorkSpec> workSpecs) { for (ConstraintController controller : mConstraintControllers) { controller.replace(workSpecs); } } WorkConstraintsTracker(Context context, @Nullable WorkConstraintsCallback callback); @VisibleForTesting  WorkConstraintsTracker(
            @Nullable WorkConstraintsCallback callback,
            ConstraintController[] controllers); void replace(@NonNull List<WorkSpec> workSpecs); void reset(); boolean areAllConstraintsMet(@NonNull String workSpecId); @Override void onConstraintMet(@NonNull List<String> workSpecIds); @Override void onConstraintNotMet(@NonNull List<String> workSpecIds);  }### Answer:
@Test public void testReplace() { List<WorkSpec> emptyList = Collections.emptyList(); mWorkConstraintsTracker.replace(emptyList); verify(mMockController).replace(emptyList); }