@Test
public void checkAdditionNewURL()
        throws Exception {

    URL url1 = new URL("http", "host", 9000, "filename1");
    URL url2 =  new URL("http", "host", 9000, "filename2");
    URL url3 =  new URL("http", "host", 9000, "filename1");
    ExpansibleURLClassLoader cl = new ExpansibleURLClassLoader(new URL[]{url1});
    assertNotNull(cl);
    cl.addUrl(url2);
    cl.addUrl(url3);
    URL[] result = cl.getURLs();
    assertSame(result[0], url1);
    assertSame(result[1], url2);
    assertEquals(result.length, 2);
}