Update vendored library cloud.google.com/go

vendor/cloud.google.com/go/spanner/oc_test.go

@@ -0,0 +1,72 @@
+// Copyright 2018 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build go1.8
+
+package spanner
+
+import (
+	"testing"
+	"time"
+
+	"cloud.google.com/go/spanner/internal/testutil"
+	"go.opencensus.io/plugin/ocgrpc"
+	statsview "go.opencensus.io/stats/view"
+	"golang.org/x/net/context"
+	"google.golang.org/api/option"
+	"google.golang.org/grpc"
+)
+
+func TestOCStats(t *testing.T) {
+	// Check that stats are being exported.
+	te := &testExporter{c: make(chan *statsview.Data)}
+	statsview.RegisterExporter(te)
+	defer statsview.UnregisterExporter(te)
+	statsview.SetReportingPeriod(time.Millisecond)
+	if err := ocgrpc.ClientRequestCountView.Subscribe(); err != nil {
+		t.Fatal(err)
+	}
+	ms := testutil.NewMockCloudSpanner(t, trxTs)
+	ms.Serve()
+	ctx := context.Background()
+	c, err := NewClient(ctx, "projects/P/instances/I/databases/D",
+		option.WithEndpoint(ms.Addr()),
+		option.WithGRPCDialOption(grpc.WithInsecure()),
+		option.WithoutAuthentication())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+
+	c.Single().ReadRow(ctx, "Users", Key{"alice"}, []string{"email"})
+	// Wait until we see data from the view.
+	select {
+	case <-te.c:
+	case <-time.After(1 * time.Second):
+		t.Fatal("no stats were exported before timeout")
+	}
+}
+
+type testExporter struct {
+	c chan *statsview.Data
+}
+
+func (e *testExporter) ExportView(vd *statsview.Data) {
+	if len(vd.Rows) > 0 {
+		select {
+		case e.c <- vd:
+		default:
+		}
+	}
+}