fix(spanner): test for client leaks

Adds a test that ensures that any started goroutine is also stopped.

Author: egonelbre

spanner/client_synctest_test.go

@@ -0,0 +1,119 @@
+//go:build go1.25
+
+/*
+Copyright 2025 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.
+*/
+
+package spanner
+
+import (
+	"context"
+	"testing"
+	"testing/synctest"
+
+	"golang.org/x/sync/errgroup"
+
+	. "cloud.google.com/go/spanner/internal/testutil"
+)
+
+func TestClient_GoroutineLeak(t *testing.T) {
+	t.Parallel()
+
+	var tests = []struct {
+		name string
+		test func(ctx context.Context, client *Client) error
+	}{
+		{
+			name: "Connect",
+			test: func(ctx context.Context, client *Client) error {
+				return nil
+			},
+		},
+		{
+			name: "Single.ReadRow",
+			test: func(ctx context.Context, client *Client) error {
+				_, err := client.Single().ReadRow(ctx, "Albums", Key{"foo"}, []string{"SingerId", "AlbumId", "AlbumTitle"})
+				return err
+			},
+		},
+		{
+			name: "ReadOnlyTransaction",
+			test: func(ctx context.Context, client *Client) error {
+				roTxn := client.ReadOnlyTransaction()
+				defer roTxn.Close()
+
+				iter := roTxn.Query(ctx, NewStatement(SelectSingerIDAlbumIDAlbumTitleFromAlbums))
+				if err := iter.Do(func(row *Row) error {
+					return nil
+				}); err != nil {
+					return err
+				}
+
+				iter = roTxn.Read(ctx, "Albums", KeySets(Key{"foo"}), []string{"SingerId", "AlbumId", "AlbumTitle"})
+				return iter.Do(func(row *Row) error {
+					return nil
+				})
+			},
+		},
+		{
+			name: "ReadWriteTransaction",
+			test: func(ctx context.Context, client *Client) error {
+				_, err := client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *ReadWriteTransaction) error {
+					iter := txn.Read(ctx, "Albums", KeySets(Key{"foo"}), []string{"SingerId", "AlbumId", "AlbumTitle"})
+					return iter.Do(func(r *Row) error {
+						return nil
+					})
+				})
+				return err
+			},
+		},
+		{
+			name: "parallel Single.ReadRow",
+			test: func(ctx context.Context, client *Client) error {
+				g := new(errgroup.Group)
+				for range 25 {
+					g.Go(func() error {
+						_, err := client.Single().ReadRow(ctx, "Albums", Key{"foo"}, []string{"SingerId", "AlbumId", "AlbumTitle"})
+						return err
+					})
+				}
+				return g.Wait()
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			server, opts, teardown := NewMockedSpannerInMemTestServer(t)
+			defer teardown()
+
+			synctest.Test(t, func(t *testing.T) {
+				ctx := t.Context()
+
+				// wait for any started goroutine to stop
+				defer synctest.Wait()
+
+				config := ClientConfig{}
+				client, err := makeClientWithConfig(ctx, "projects/p/instances/i/databases/d", config, server.ServerAddress, opts...)
+				if err != nil {
+					t.Fatalf("failed to get a client: %v", err)
+				}
+				defer client.Close()
+
+				test.test(ctx, client)
+			})
+		})
+	}
+}

spanner/internal/testutil/mocked_inmem_server.go

@@ -82,7 +82,7 @@ func NewMockedSpannerInMemTestServerWithAddr(t *testing.T, addr string, sopt ...
 	return mockedServer, opts, func() {
 		mockedServer.TestSpanner.Stop()
 		mockedServer.TestInstanceAdmin.Stop()
-		mockedServer.server.Stop()
+		mockedServer.server.GracefulStop()
 	}
 }