From 36e12e2b26547cff3eb977b61d10de5e63efab73 Mon Sep 17 00:00:00 2001
From: Yuriy Tseretyan <tceretian@gmail.com>
Date: Tue, 19 Oct 2021 16:18:44 -0400
Subject: [PATCH] Remove flakiness of google chat tests (#40592)

---
 .../ngalert/notifier/channels/googlechat.go   |  2 +-
 .../notifier/channels/googlechat_test.go      | 13 ++++-------
 .../ngalert/notifier/channels/testing.go      | 23 +++++++++++++++++++
 .../ngalert/notifier/channels/utils.go        |  8 ++++++-
 4 files changed, 36 insertions(+), 10 deletions(-)
 create mode 100644 pkg/services/ngalert/notifier/channels/testing.go

diff --git a/pkg/services/ngalert/notifier/channels/googlechat.go b/pkg/services/ngalert/notifier/channels/googlechat.go
index 56b30caf295..2f0448ac723 100644
--- a/pkg/services/ngalert/notifier/channels/googlechat.go
+++ b/pkg/services/ngalert/notifier/channels/googlechat.go
@@ -84,7 +84,7 @@ func (gcn *GoogleChatNotifier) Notify(ctx context.Context, as ...*types.Alert) (
 	// Add text paragraph widget for the build version and timestamp.
 	widgets = append(widgets, textParagraphWidget{
 		Text: text{
-			Text: "Grafana v" + setting.BuildVersion + " | " + (time.Now()).Format(time.RFC822),
+			Text: "Grafana v" + setting.BuildVersion + " | " + (timeNow()).Format(time.RFC822),
 		},
 	})
 
diff --git a/pkg/services/ngalert/notifier/channels/googlechat_test.go b/pkg/services/ngalert/notifier/channels/googlechat_test.go
index 941882e96ad..9d57958e84f 100644
--- a/pkg/services/ngalert/notifier/channels/googlechat_test.go
+++ b/pkg/services/ngalert/notifier/channels/googlechat_test.go
@@ -19,6 +19,9 @@ import (
 )
 
 func TestGoogleChatNotifier(t *testing.T) {
+	constNow := time.Now()
+	defer mockTimeNow(constNow)()
+
 	tmpl := templateForTests(t)
 
 	externalURL, err := url.Parse("http://localhost")
@@ -77,7 +80,7 @@ func TestGoogleChatNotifier(t *testing.T) {
 									textParagraphWidget{
 										Text: text{
 											// RFC822 only has the minute, hence it works in most cases.
-											Text: "Grafana v" + setting.BuildVersion + " | " + (time.Now()).Format(time.RFC822),
+											Text: "Grafana v" + setting.BuildVersion + " | " + constNow.Format(time.RFC822),
 										},
 									},
 								},
@@ -135,7 +138,7 @@ func TestGoogleChatNotifier(t *testing.T) {
 									},
 									textParagraphWidget{
 										Text: text{
-											Text: "Grafana v" + setting.BuildVersion + " | " + (time.Now()).Format(time.RFC822),
+											Text: "Grafana v" + setting.BuildVersion + " | " + constNow.Format(time.RFC822),
 										},
 									},
 								},
@@ -177,12 +180,6 @@ func TestGoogleChatNotifier(t *testing.T) {
 				return nil
 			})
 
-			if time.Now().Second() == 59 {
-				// The notification payload has a time component with a precision
-				// of minute. So if we are at the edge of a minute, we delay for 1 second
-				// to avoid any flakiness.
-				time.Sleep(1 * time.Second)
-			}
 			ctx := notify.WithGroupKey(context.Background(), "alertname")
 			ctx = notify.WithGroupLabels(ctx, model.LabelSet{"alertname": ""})
 			ok, err := pn.Notify(ctx, c.alerts...)
diff --git a/pkg/services/ngalert/notifier/channels/testing.go b/pkg/services/ngalert/notifier/channels/testing.go
new file mode 100644
index 00000000000..0f22f81ebbb
--- /dev/null
+++ b/pkg/services/ngalert/notifier/channels/testing.go
@@ -0,0 +1,23 @@
+package channels
+
+import "time"
+
+// mockTimeNow replaces function timeNow to return constant time.
+// It returns a function that resets the variable back to its original value.
+// This allows usage of this function with defer:
+// func Test (t *testing.T) {
+//    now := time.Now()
+//    defer mockTimeNow(now)()
+//    ...
+// }
+func mockTimeNow(constTime time.Time) func() {
+	timeNow = func() time.Time {
+		return constTime
+	}
+	return resetTimeNow
+}
+
+// resetTimeNow resets the global variable timeNow to the default value, which is time.Now
+func resetTimeNow() {
+	timeNow = time.Now
+}
diff --git a/pkg/services/ngalert/notifier/channels/utils.go b/pkg/services/ngalert/notifier/channels/utils.go
index 6308553b8e3..aebdc360eb6 100644
--- a/pkg/services/ngalert/notifier/channels/utils.go
+++ b/pkg/services/ngalert/notifier/channels/utils.go
@@ -12,9 +12,10 @@ import (
 	"path"
 	"time"
 
+	"github.com/prometheus/common/model"
+
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/util"
-	"github.com/prometheus/common/model"
 
 	"github.com/grafana/grafana/pkg/components/simplejson"
 )
@@ -25,6 +26,11 @@ const (
 	ColorAlertResolved = "#36a64f"
 )
 
+var (
+	// Provides current time. Can be overwritten in tests.
+	timeNow = time.Now
+)
+
 type receiverInitError struct {
 	Reason string
 	Err    error