Artificial delay for testing

view/json.go

@@ -11,6 +11,7 @@ import (
 	"log"
 	"net/http"
 	"strings"
+	"time"
 
 	"golang.org/x/time/rate"
 )
@@ -60,6 +61,10 @@ func jsonHandler(g storage.RateLimitedGraph) http.Handler {
 		foo := route.foo
 		auth := !route.noauth
 		mux.HandleFunc(route.path, func(w http.ResponseWriter, r *http.Request) {
+			if err := delay(w, r); err != nil {
+				http.Error(w, err.Error(), 499)
+			}
+
 			if auth {
 				if err := Auth(g, w, r); err != nil {
 					return
@@ -134,3 +139,12 @@ func version(_ storage.RateLimitedGraph, w http.ResponseWriter, _ *http.Request)
 	enc.SetIndent("", "   ")
 	return enc.Encode(map[string]string{"version": GitCommit})
 }
+
+func delay(w http.ResponseWriter, r *http.Request) error {
+	select {
+	case <-time.After(config.New().Delay):
+	case <-r.Context().Done():
+		return errors.New("client DCd")
+	}
+	return nil
+}

view/json_test.go

@@ -125,3 +125,35 @@ func TestVersion(t *testing.T) {
 		}
 	})
 }
+
+func TestDelay(t *testing.T) {
+	defer func() {
+		os.Setenv("DELAY", "0ms")
+	}()
+	os.Args = os.Args[:1]
+	os.Setenv("DELAY", "100ms")
+
+	r := httptest.NewRequest("GET", "/", nil)
+	w := httptest.NewRecorder()
+
+	start := time.Now()
+	if err := delay(w, r); err != nil {
+		t.Fatal(err)
+	}
+	if since := time.Since(start); since < time.Millisecond*100 {
+		t.Fatal(since)
+	}
+
+	r = httptest.NewRequest("GET", "/", nil)
+	ctx, can := context.WithCancel(r.Context())
+	can()
+	r = r.WithContext(ctx)
+	w = httptest.NewRecorder()
+	start = time.Now()
+	if err := delay(w, r); err == nil {
+		t.Fatal(err)
+	}
+	if since := time.Since(start); since > time.Millisecond*99 {
+		t.Fatal(since)
+	}
+}