@Test(expected = IOException.class)
public void testReadInTextFile() throws IOException {

  final ImageFileSource fileSource = new ImageFileSource(osf, origin -> null, this
      .textFile);
  fileSource.initialize();
  OutputSocket<MatWrapper> outputSocket = fileSource.getOutputSockets().get(0);
  assertTrue("No matrix should have been returned.", outputSocket.getValue().get().empty());
}