generator.addSampleInstances(String.class, ImmutableList.of("a"));
    assertEquals("a", generator.generateFresh(String.class));
    assertEquals("a", generator.generateFresh(String.class));
  }

  public void testAddSampleInstances_noInstance() {
    FreshValueGenerator generator = new FreshValueGenerator();
    generator.addSampleInstances(String.class, ImmutableList.<String>of());