@Test
public void testToString() {

    assertEquals("//127.0.0.1:8080", new Proxy("127.0.0.1", 8080).toString());
    assertEquals("http://127.0.0.1:8080", new Proxy("127.0.0.1", 8080, "http").toString());
    assertEquals("//username:password@127.0.0.1:8080", new Proxy("127.0.0.1", 8080, "username", "password").toString());
    assertEquals("//username@127.0.0.1:8080", new Proxy("127.0.0.1", 8080, "username", null).toString());
    assertEquals("//:password@127.0.0.1:8080", new Proxy("127.0.0.1", 8080, null, "password").toString());
}