racer: refactor code to not repeat

racer/racer.go

@@ -7,17 +7,19 @@ import (
 )
 
 func Racer(a, b string) string {
-	startA := time.Now()
+	aDuration := measureResponseTime(a)
-	http.Get(a)
+	bDuration := measureResponseTime(b)
-	aDuration := time.Since(startA)
-	fmt.Println(aDuration)
 
-	startB := time.Now()
-	http.Get(b)
-	bDuration := time.Since(startB)
-	fmt.Println(bDuration)
 	if aDuration < bDuration {
 		return a
 	}
 	return b
 }
+
+func measureResponseTime(url string) time.Duration {
+	start := time.Now()
+	http.Get(url)
+	duration := time.Since(start)
+	fmt.Println(duration)
+	return duration
+}

racer/racer_test.go

@@ -8,17 +8,10 @@ import (
 )
 
 func TestRacer(t *testing.T) {
-	slowServer := httptest.NewServer(http.HandlerFunc(
+	slowServer := makeDelayedServer(20 * time.Millisecond)
-		func(w http.ResponseWriter, r *http.Request) {
-			time.Sleep(20 * time.Millisecond)
-			w.WriteHeader(http.StatusOK)
-		}))
 	defer slowServer.Close()
 
-	fastServer := httptest.NewServer(http.HandlerFunc(
+	fastServer := makeDelayedServer(0 * time.Millisecond)
-		func(w http.ResponseWriter, r *http.Request) {
-			w.WriteHeader(http.StatusOK)
-		}))
 	defer fastServer.Close()
 
 	slowURL := slowServer.URL
@@ -31,3 +24,11 @@ func TestRacer(t *testing.T) {
 		t.Errorf("got %q, want %q", got, want)
 	}
 }
+
+func makeDelayedServer(delay time.Duration) *httptest.Server {
+	return httptest.NewServer(http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			time.Sleep(delay)
+			w.WriteHeader(http.StatusOK)
+		}))
+}