diff --git a/cmd/prometheus/main_test.go b/cmd/prometheus/main_test.go
index 2e1795c0b..7dec5b9a5 100644
--- a/cmd/prometheus/main_test.go
+++ b/cmd/prometheus/main_test.go
@@ -147,8 +147,8 @@ func TestSendAlerts(t *testing.T) {
 		{
 			in: []*rules.Alert{
 				{
-					Labels:      []labels.Label{{Name: "l1", Value: "v1"}},
-					Annotations: []labels.Label{{Name: "a2", Value: "v2"}},
+					Labels:      labels.FromStrings("l1", "v1"),
+					Annotations: labels.FromStrings("a2", "v2"),
 					ActiveAt:    time.Unix(1, 0),
 					FiredAt:     time.Unix(2, 0),
 					ValidUntil:  time.Unix(3, 0),
@@ -156,8 +156,8 @@ func TestSendAlerts(t *testing.T) {
 			},
 			exp: []*notifier.Alert{
 				{
-					Labels:       []labels.Label{{Name: "l1", Value: "v1"}},
-					Annotations:  []labels.Label{{Name: "a2", Value: "v2"}},
+					Labels:       labels.FromStrings("l1", "v1"),
+					Annotations:  labels.FromStrings("a2", "v2"),
 					StartsAt:     time.Unix(2, 0),
 					EndsAt:       time.Unix(3, 0),
 					GeneratorURL: "http://localhost:9090/graph?g0.expr=up&g0.tab=1",
@@ -167,8 +167,8 @@ func TestSendAlerts(t *testing.T) {
 		{
 			in: []*rules.Alert{
 				{
-					Labels:      []labels.Label{{Name: "l1", Value: "v1"}},
-					Annotations: []labels.Label{{Name: "a2", Value: "v2"}},
+					Labels:      labels.FromStrings("l1", "v1"),
+					Annotations: labels.FromStrings("a2", "v2"),
 					ActiveAt:    time.Unix(1, 0),
 					FiredAt:     time.Unix(2, 0),
 					ResolvedAt:  time.Unix(4, 0),
@@ -176,8 +176,8 @@ func TestSendAlerts(t *testing.T) {
 			},
 			exp: []*notifier.Alert{
 				{
-					Labels:       []labels.Label{{Name: "l1", Value: "v1"}},
-					Annotations:  []labels.Label{{Name: "a2", Value: "v2"}},
+					Labels:       labels.FromStrings("l1", "v1"),
+					Annotations:  labels.FromStrings("a2", "v2"),
 					StartsAt:     time.Unix(2, 0),
 					EndsAt:       time.Unix(4, 0),
 					GeneratorURL: "http://localhost:9090/graph?g0.expr=up&g0.tab=1",