ts.addTest(new SimpleModelTest("testAddingDuplicates"));
  public static Test suite()  {    TestSuite ts = new TestSuite("SimpleModelTest");    ts.addTest(new SimpleModelTest("testPackageAndFactory"));    ts.addTest(new SimpleModelTest("testAttributes"));    ts.addTest(new SimpleModelTest("testReference"));    ts.addTest(new SimpleModelTest("testMetaData"));    ts.addTest(new SimpleModelTest("testSaveAndLoad"));    ts.addTest(new SimpleModelTest("testSaveAndLoadZip"));    ts.addTest(new SimpleModelTest("testProxy"));    ts.addTest(new SimpleModelTest("testTrackingModificaiton"));    return ts;  }