@Test
 public void testDeleteFeature() {
   featureContainer.getFeatureDictionary().put("feature1", mockedFeature1);
   featureContainer.getFeatureStorage().put(mockedFeature1.getFeatureStem(), mockedFeature1);
   featureContainer.deleteFeature("feature1");
   Assert.assertNull(featureContainer.getFeatureDictionary().get("feature1"));
 }
  @Test
  public void testAddFeatureStemmingEnabled() {
    Annotation mockedAnnot1 = Mockito.mock(Annotation.class);
    Annotation mockedAnnot2 = Mockito.mock(Annotation.class);
    FeatureMap mockedMap1 = Mockito.mock(FeatureMap.class);
    FeatureMap mockedMap2 = Mockito.mock(FeatureMap.class);
    Node startNode = Mockito.mock(Node.class);
    Node endNode = Mockito.mock(Node.class);

    String wholeSentence = "First Second Third Fourth.";

    Mockito.when(startNode.getOffset()).thenReturn((long) 0);
    Mockito.when(endNode.getOffset()).thenReturn((long) 11);

    Mockito.when(mockedAnnot1.getFeatures()).thenReturn(mockedMap1);
    Mockito.when(mockedMap1.get("string")).thenReturn("First");
    Mockito.when(mockedMap1.get("stem")).thenReturn("stem1");
    Mockito.when(mockedAnnot1.getStartNode()).thenReturn(startNode);

    Mockito.when(mockedAnnot2.getFeatures()).thenReturn(mockedMap2);
    Mockito.when(mockedMap2.get("string")).thenReturn("Second");
    Mockito.when(mockedMap2.get("stem")).thenReturn("stem2");
    Mockito.when(mockedAnnot2.getEndNode()).thenReturn(endNode);

    Document gateDocument = Mockito.mock(Document.class);
    Mockito.when(gateDocument.getName()).thenReturn("doc1");

    ArrayList<Annotation> featureAnnots = new ArrayList<Annotation>();
    featureAnnots.add(mockedAnnot1);
    featureAnnots.add(mockedAnnot2);

    Mockito.when(options.isEnableStemming()).thenReturn(true);

    String featureString = "First Second";
    String featureStem = "stem1 stem2";
    featureContainer.addFeature(featureAnnots, wholeSentence, gateDocument, "content");

    Assert.assertTrue(featureContainer.getFeatureDictionary().get(featureString) != null);
    Assert.assertTrue(featureContainer.getFeatureStorage().get(featureStem) != null);
  }