code: @Test public void testIsFrameValid() throws Exception {
    DefaultExtension defaultExtension=new DefaultExtension();
    TextFrame textFrame=new TextFrame();
    try {
      defaultExtension.isFrameValid(textFrame);
    }
   catch (  Exception e) {
      fail("This frame is valid");
    }
    textFrame.setRSV1(true);
    try {
      defaultExtension.isFrameValid(textFrame);
      fail("This frame is not valid");
    }
   catch (  Exception e) {
    }
    textFrame.setRSV1(false);
    textFrame.setRSV2(true);
    try {
      defaultExtension.isFrameValid(textFrame);
      fail("This frame is not valid");
    }
   catch (  Exception e) {
    }
    textFrame.setRSV2(false);
    textFrame.setRSV3(true);
    try {
      defaultExtension.isFrameValid(textFrame);
      fail("This frame is not valid");
    }
   catch (  Exception e) {
    }
  }
  