@Test
  public void wordsWithPrefixAndKTest() {
    pm.wordsWithPrefix("test", 4).iterator();

    verify(trieMock, times(1)).wordsWithPrefix("test");
  }
  @Test
  public void sizeTest() {
    pm.size();

    verify(trieMock).size();
  }
  @Test
  public void containsTest() {
    pm.contains("test");

    verify(trieMock).contains(any(String.class));
  }
  @Test
  public void deleteTest() {
    pm.delete("test");

    verify(trieMock).delete(any(String.class));
  }
  @Test
  public void addCallsSizeTwoTimesTest() {
    pm.add(new String[] {"testa", "testb"});

    verify(trieMock, times(2)).size();
  }
  @Test
  public void addTest() {
    pm.add(new String[] {"testa", "testb"});

    verify(trieMock, atLeastOnce()).add(any(Tuple.class));
  }