cst.ts.Config.ErrorLog = log.New(testLogWriter{t}, "", 0)
	}

	switch mode {
	case http1Mode:
		cst.ts.Start()
	case https1Mode:
		cst.ts.StartTLS()
	case http2Mode:
		ExportHttp2ConfigureServer(cst.ts.Config, nil)
		cst.ts.TLS = cst.ts.Config.TLSConfig
		cst.ts.StartTLS()
	default:
		t.Fatalf("unknown test mode %v", mode)
	}
	cst.c = cst.ts.Client()
	cst.tr = cst.c.Transport.(*Transport)