### Question:
DefaultStorIOSQLite extends StorIOSQLite { @Override @NonNull public Flowable<Changes> observeChangesOfTags(@NonNull final Set<String> tags, @NonNull BackpressureStrategy backpressureStrategy) { return ChangesFilter.applyForTags(observeChanges(backpressureStrategy), tags); } protected  DefaultStorIOSQLite(
            @NonNull SQLiteOpenHelper sqLiteOpenHelper,
            @NonNull TypeMappingFinder typeMappingFinder,
            @Nullable Scheduler defaultRxScheduler,
            @NonNull List<Interceptor> interceptors); @NonNull @Override Flowable<Changes> observeChanges(@NonNull BackpressureStrategy backpressureStrategy); @Override @NonNull Flowable<Changes> observeChangesInTables(@NonNull final Set<String> tables, @NonNull BackpressureStrategy backpressureStrategy); @Override @NonNull Flowable<Changes> observeChangesOfTags(@NonNull final Set<String> tags, @NonNull BackpressureStrategy backpressureStrategy); @Override Scheduler defaultRxScheduler(); @NonNull @Override LowLevel lowLevel(); @NonNull @Override List<Interceptor> interceptors(); @Override void close(); @NonNull static Builder builder();  }### Answer:
@Test public void observeChangesOfTagsShouldNotAcceptNullAsTags() { expectedException.expect(NullPointerException.class); expectedException.expectMessage("Set of tags can not be null"); expectedException.expectCause(nullValue(Throwable.class)); storIOSQLite.observeChangesOfTags(null, LATEST); }