### Question:
FederatedRepositoryImpl implements FederatedRepository { @Override public FederatedDataSet getTestData() { return dataSource.getTestData(); } FederatedRepositoryImpl(FederatedDataSource dataSource, FederatedNetworkDataSource networkDataSource); @Override FederatedDataSet getTrainingData(); @Override FederatedDataSet getTestData(); @Override FederatedDataSet getCrossValidationData(); @Override Observable<Boolean> uploadGradient(byte[] gradient); @Override Observable<byte[]> retrieveGradient(); @Override Observable<Integer> registerModel();  }### Answer:
@Test public void testGetTestData() { given(dataSource.getTestData()).willReturn(dataSet); FederatedDataSet testData = cut.getTestData(); assertNotNull(testData); }