@Test(expectedExceptions = IllegalArgumentException.class)
 public void testHttpsWithEmptyCertFile() {
   Connectors.https(mock(Server.class), 1010, "", "ewerk");
   failBecauseExceptionWasNotThrown(IllegalArgumentException.class);
 }
 @Test(expectedExceptions = IllegalArgumentException.class)
 public void testHttpsWithNullServer() {
   Connectors.https(null, 1010, null, null);
   failBecauseExceptionWasNotThrown(IllegalArgumentException.class);
 }