Add some race-detector tests

filter/txnBuf/race_test.go

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package txnBuf
+
+import (
+        "sync"
+        "testing"
+
+        "github.com/luci/gae/impl/memory"
+        "github.com/luci/gae/service/datastore"
+        "golang.org/x/net/context"
+)
+
+type Counter struct {
+        ID int64 `gae:"$id"`
+
+        Value int64
+}
+
+func TestRace(t *testing.T) {
+        t.Parallel()
+
+        c := FilterRDS(memory.Use(context.Background()))
+        ds := datastore.Get(c)
+
+        wg := sync.WaitGroup{}
+        for i := 0; i < 100; i++ {
+                id := int64(i + 1)
+
+                wg.Add(1)
+                go func() {
+                        defer wg.Done()
+                        err := ds.RunInTransaction(func(c context.Context) error {
+                                ds := datastore.Get(c)
+
+                                for i := 0; i < 100; i++ {
+                                        err := ds.RunInTransaction(func(c context.Context) error {
+                                                ds := datastore.Get(c)
+
+                                                ctr := &Counter{ID: id}
+                                                if err := ds.Get(ctr); err != nil && err != datastore.ErrNoSuchEntity {
+                                                        t.Fatal("bad Get", err)
+                                                }
+                                                ctr.Value++
+                                                return ds.Put(ctr)
+                                        }, nil)
+                                        if err != nil {
+                                                t.Fatal("bad inner RIT", err)
+                                        }
+                                }
+
+                                return nil
+                        }, nil)
+                        if err != nil {
+                                t.Fatal("bad outer RIT", err)
+                        }
+                }()
+        }
+        wg.Wait()
+}