    def test_is_valid_matrix_server_name(self):
        """Tests that the is_valid_matrix_server_name function accepts only
        valid hostnames (or domain names), with optional port number.
        """
        self.assertTrue(is_valid_matrix_server_name("9.9.9.9"))
        self.assertTrue(is_valid_matrix_server_name("9.9.9.9:4242"))
        self.assertTrue(is_valid_matrix_server_name("[::]"))
        self.assertTrue(is_valid_matrix_server_name("[::]:4242"))
        self.assertTrue(is_valid_matrix_server_name("[a:b:c::]:4242"))

        self.assertTrue(is_valid_matrix_server_name("example.com"))
        self.assertTrue(is_valid_matrix_server_name("EXAMPLE.COM"))
        self.assertTrue(is_valid_matrix_server_name("ExAmPlE.CoM"))
        self.assertTrue(is_valid_matrix_server_name("example.com:4242"))
        self.assertTrue(is_valid_matrix_server_name("localhost"))
        self.assertTrue(is_valid_matrix_server_name("localhost:9000"))
        self.assertTrue(is_valid_matrix_server_name("a.b.c.d:1234"))

        self.assertFalse(is_valid_matrix_server_name("[:::]"))
        self.assertFalse(is_valid_matrix_server_name("a:b:c::"))

        self.assertFalse(is_valid_matrix_server_name("example.com:65536"))
        self.assertFalse(is_valid_matrix_server_name("example.com:0"))
        self.assertFalse(is_valid_matrix_server_name("example.com:-1"))
        self.assertFalse(is_valid_matrix_server_name("example.com:a"))
        self.assertFalse(is_valid_matrix_server_name("example.com: "))
        self.assertFalse(is_valid_matrix_server_name("example.com:04242"))
        self.assertFalse(is_valid_matrix_server_name("example.com: 4242"))
        self.assertFalse(is_valid_matrix_server_name("example.com/example.com"))
        self.assertFalse(is_valid_matrix_server_name("example.com#example.com"))
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.