don't use default transport for proxy, causing race with tests

app/proxy/health_test.go

@@ -53,7 +53,7 @@ func TestHttp_healthHandler(t *testing.T) {
 	go func() {
 		_ = h.Run(ctx)
 	}()
-	time.Sleep(10 * time.Millisecond)
+	time.Sleep(20 * time.Millisecond)
 
 	client := http.Client{}
 	req, err := http.NewRequest("GET", "http://127.0.0.1:"+strconv.Itoa(port)+"/health", nil)

app/proxy/proxy.go

@@ -141,8 +141,18 @@ func (h *Http) proxyHandler() http.HandlerFunc {
 		},
 	}
 
-	reverseProxy.Transport = http.DefaultTransport
-	reverseProxy.Transport.(*http.Transport).ResponseHeaderTimeout = h.TimeOut
+	reverseProxy.Transport = &http.Transport{
+		ResponseHeaderTimeout: h.TimeOut,
+		DialContext: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+		}).DialContext,
+		ForceAttemptHTTP2:     true,
+		MaxIdleConns:          100,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+	}
 
 	// default assetsHandler disabled, returns error on missing matches
 	assetsHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

app/proxy/proxy_test.go

@@ -42,6 +42,7 @@ func TestHttp_Do(t *testing.T) {
 		_ = svc.Run(context.Background())
 	}()
 
+	time.Sleep(10 * time.Millisecond)
 	h.Matcher = svc
 	go func() {
 		_ = h.Run(ctx)
@@ -113,7 +114,7 @@ func TestHttp_DoWithAssets(t *testing.T) {
 	go func() {
 		_ = svc.Run(context.Background())
 	}()
-
+	time.Sleep(10 * time.Millisecond)
 	h.Matcher = svc
 	go func() {
 		_ = h.Run(ctx)