You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: sinks_test.go
    path of file: ./repos/gitkube/vendor/cloud.google.com/go/logging/logadmin
    
    the code of the file until where you have to start completion: // Copyright 2016 Google LLC
//
// 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.

// TODO(jba): document in CONTRIBUTING.md that service account must be given "Logs Configuration Writer" IAM role for sink tests to pass.
// TODO(jba): [cont] (1) From top left menu, go to IAM & Admin. (2) In Roles dropdown for acct, select Logging > Logs Configuration Writer. (3) Save.
// TODO(jba): Also, cloud-logs@google.com must have Owner permission on the GCS bucket named for the test project
    
func TestCreateDeleteSink(t *testing.T) {
	ctx := context.Background()
	sink := &Sink{
		ID:              sinkIDs.New(),
		Destination:     testSinkDestination,
		Filter:          testFilter,
		IncludeChildren: true,
	}
	got, err := client.CreateSink(ctx, sink)
	if err != nil {
		t.Fatal(err)
	}
	defer client.DeleteSink(ctx, sink.ID)
	sink.WriterIdentity = ltest.SharedServiceAccount
	if want := sink; !testutil.Equal(got, want) {
		t.Errorf("got %+v, want %+v", got, want)
	}
	got, err = client.Sink(ctx, sink.ID)
	if err != nil {
		t.Fatal(err)
	}
	if want := sink; !testutil.Equal(got, want) {
		t.Errorf("got %+v, want %+v", got, want)
	}

	if err := client.DeleteSink(ctx, sink.ID); err != nil {
		t.Fatal(err)
	}

	if _, err := client.Sink(ctx, sink.ID); err == nil {
		t.Fatal("got no error, expected one")
	}

	// UniqueWriterIdentity
	sink.ID = sinkIDs.New()
	got, err = client.CreateSinkOpt(ctx, sink, SinkOptions{UniqueWriterIdentity: true})
	if err != nil {
		t.Fatal(err)
	}
	defer client.DeleteSink(ctx, sink.ID)
	// The WriterIdentity should be different.
	if got.WriterIdentity == sink.WriterIdentity {
		t.Errorf("got %s, want something different", got.WriterIdentity)
	}
}