@Test
 public final void testSetTitle() {
   testGetTitle();
   siExtended.setTitle("Hey");
   assertEquals("Hey", siExtended.getTitle());
 }
 @Test
 public final void testSongInfo() {
   assertEquals(null, siBasic.getArtist());
   assertEquals(null, siBasic.getTitle());
 }
 @Test
 public final void testGetTitle() {
   // siBasic.setInterpret("Steven");
   assertEquals("I only sing in the shower", siExtended.getTitle());
 }
 @Test
 public final void testSongInfoStringString() {
   assertEquals("Hendrik", siExtended.getArtist());
   assertEquals("I only sing in the shower", siExtended.getTitle());
 }