RsJsCore extends AbstractRsJs { @Override List<InputStream> getStreams() { List<InputStream> streams = new ArrayList<>(); addStream(streams, getJsCore()); return streams; }    }
@Test public void testGetStreams() { System.out.println("getStreams"); doReturn("").when(instance).getJsFilename(anyString(), anyString()); doReturn("").when(instance).getJsCore(); List<InputStream> result = instance.getStreams(); verify(instance).addStream(any(List.class), anyString()); assertThat(result).isNotNull(); }