Merge pull request prometheus#7385 from brancz/fix-flaky-kube-test

discovery/kubernetes: Fix incorrect premature break of reading results

discovery/kubernetes/kubernetes_test.go

@@ -107,36 +107,30 @@ func (d k8sDiscoveryTest) Run(t *testing.T) {
 // readResultWithTimeout reads all targegroups from channel with timeout.
 // It merges targegroups by source and sends the result to result channel.
 func readResultWithTimeout(t *testing.T, ch <-chan []*targetgroup.Group, max int, timeout time.Duration, resChan chan<- map[string]*targetgroup.Group) {
-	allTgs := make([][]*targetgroup.Group, 0)
-
+	res := make(map[string]*targetgroup.Group)
 Loop:
 	for {
 		select {
 		case tgs := <-ch:
-			allTgs = append(allTgs, tgs)
-			if len(allTgs) == max {
+			for _, tg := range tgs {
+				if tg == nil {
+					continue
+				}
+				res[tg.Source] = tg
+			}
+			if len(res) == max {
 				// Reached max target groups we may get, break fast.
 				break Loop
 			}
 		case <-time.After(timeout):
 			// Because we use queue, an object that is created then
 			// deleted or updated may be processed only once.
 			// So possibly we may skip events, timed out here.
-			t.Logf("timed out, got %d (max: %d) items, some events are skipped", len(allTgs), max)
+			t.Logf("timed out, got %d (max: %d) items, some events are skipped", len(res), max)
 			break Loop
 		}
 	}
 
-	// Merge by source and sent it to channel.
-	res := make(map[string]*targetgroup.Group)
-	for _, tgs := range allTgs {
-		for _, tg := range tgs {
-			if tg == nil {
-				continue
-			}
-			res[tg.Source] = tg
-		}
-	}
 	resChan <- res
 }