@Test
public void checkNetworkTwts() throws IOException {

    Network network = Mockito.mock(Network.class);
    Mockito.when(network.getId()).thenReturn("network");
    Mockito.when(network.getTwoWindingsTransformerStream()).thenAnswer(dummy -> Stream.of(transformer));
    assertTrue(TransformersValidation.INSTANCE.checkTransformers(network, strictConfig, data));
    assertTrue(ValidationType.TWTS.check(network, strictConfig, tmpDir));
    ValidationWriter validationWriter = ValidationUtils.createValidationWriter(network.getId(), strictConfig, NullWriter.NULL_WRITER, ValidationType.TWTS);
    assertTrue(ValidationType.TWTS.check(network, strictConfig, validationWriter));
}