clientv3/integration: KV APIs match grpc.ErrClientConnClosing

Signed-off-by: Gyu-Ho Lee <gyuhox@gmail.com>

clientv3/integration/kv_test.go

@@ -791,8 +791,8 @@ func TestKVGetStoppedServerAndClose(t *testing.T) {
 	// this Get fails and triggers an asynchronous connection retry
 	_, err := cli.Get(ctx, "abc")
 	cancel()
-	if !strings.Contains(err.Error(), "context deadline") {
-		t.Fatal(err)
+	if err != grpc.ErrClientConnClosing {
+		t.Fatalf("expected %v, got %v", grpc.ErrClientConnClosing, err)
 	}
 }
 
@@ -813,15 +813,15 @@ func TestKVPutStoppedServerAndClose(t *testing.T) {
 	// grpc finds out the original connection is down due to the member shutdown.
 	_, err := cli.Get(ctx, "abc")
 	cancel()
-	if !strings.Contains(err.Error(), "context deadline") {
-		t.Fatal(err)
+	if err != grpc.ErrClientConnClosing {
+		t.Fatalf("expected %v, got %v", grpc.ErrClientConnClosing, err)
 	}
 
 	// this Put fails and triggers an asynchronous connection retry
 	_, err = cli.Put(ctx, "abc", "123")
 	cancel()
-	if !strings.Contains(err.Error(), "context deadline") {
-		t.Fatal(err)
+	if err != grpc.ErrClientConnClosing {
+		t.Fatalf("expected %v, got %v", grpc.ErrClientConnClosing, err)
 	}
 }