testCases := []struct {
		hostPort     string
		expectedHost string
		expectedPort string
	}{
		{":54321", "", "54321"},
		{"server:54321", "server", "54321"},
		{":0", "", "0"},
		{"server:https", "server", "443"},
		{"server:http", "server", "80"},
	}

	for _, testCase := range testCases {
		host, port := mustSplitHostPort(testCase.hostPort)
		if testCase.expectedHost != host {