From 06493b7034e31099246d7ecc9bcde73dedcb383d Mon Sep 17 00:00:00 2001
From: ZouYu <zouy.fnst@cn.fujitsu.com>
Date: Wed, 22 Apr 2020 15:02:47 +0800
Subject: [PATCH] add unit test TestLabels_String for pkg/labels/labels.go
 (#7150)

Signed-off-by: ZouYu <zouy.fnst@cn.fujitsu.com>
---
 pkg/labels/labels_test.go | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/pkg/labels/labels_test.go b/pkg/labels/labels_test.go
index cf82a8dde..576a26752 100644
--- a/pkg/labels/labels_test.go
+++ b/pkg/labels/labels_test.go
@@ -19,6 +19,39 @@ import (
 	"github.com/prometheus/prometheus/util/testutil"
 )
 
+func TestLabels_String(t *testing.T) {
+	cases := []struct {
+		lables   Labels
+		expected string
+	}{
+		{
+			lables: Labels{
+				{
+					Name:  "t1",
+					Value: "t1",
+				},
+				{
+					Name:  "t2",
+					Value: "t2",
+				},
+			},
+			expected: "{t1=\"t1\", t2=\"t2\"}",
+		},
+		{
+			lables:   Labels{},
+			expected: "{}",
+		},
+		{
+			lables:   nil,
+			expected: "{}",
+		},
+	}
+	for _, c := range cases {
+		str := c.lables.String()
+		testutil.Equals(t, c.expected, str)
+	}
+}
+
 func TestLabels_MatchLabels(t *testing.T) {
 	labels := Labels{
 		{