Add some race-detector tests

impl/memory/race_test.go

Index: impl/memory/race_test.go
diff --git a/impl/memory/race_test.go b/impl/memory/race_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..713e6cab04e6b9b5719175f5c7ecab1b67435a8b
--- /dev/null
+++ b/impl/memory/race_test.go
@@ -0,0 +1,101 @@
+// 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 memory
+
+import (
+	"sync"
+	"sync/atomic"
+	"testing"
+
+	"github.com/luci/gae/service/datastore"
+	"golang.org/x/net/context"
+)
+
+func TestRaceGetPut(t *testing.T) {
+	t.Parallel()
+
+	value := new(int64)

[dnj, 2015/11/10 00:20:20]

nit: int64(0), use &value elsewhere.

[iannucci, 2015/11/11 18:13:58]

*shrug*

+	num := new(int64)
+
+	ds := datastore.Get(Use(context.Background()))
+
+	wg := sync.WaitGroup{}
+
+	for i := 0; i < 100; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+
+			err := ds.RunInTransaction(func(c context.Context) error {
+				atomic.AddInt64(num, 1)
+
+				ds := datastore.Get(c)
+
+				obj := pmap("$key", ds.MakeKey("Obj", 1))
+				if err := ds.Get(obj); err != nil && err != datastore.ErrNoSuchEntity {
+					t.Fatal("error get", err)
+				}
+				cur := int64(0)
+				if ps, ok := obj["Value"]; ok {
+					cur = ps[0].Value().(int64)
+				}
+
+				cur++
+				obj["Value"] = []datastore.Property{prop(cur)}
+
+				return ds.Put(obj)
+			}, &datastore.TransactionOptions{Attempts: 200})
+
+			if err != nil {
+				t.Fatal("error during transaction", err)
+			}
+
+			atomic.AddInt64(value, 1)

[dnj, 2015/11/10 00:20:20]

This may break on 32-bit systems b/c not allocated as the first member of a
struct; why not just use int32's here and avoid the issue?

[iannucci, 2015/11/11 18:13:58]

it's allocated so it's fine

+		}()
+	}
+	wg.Wait()
+
+	obj := pmap("$key", ds.MakeKey("Obj", 1))
+	if ds.Get(obj) != nil {
+		t.FailNow()
+	}
+	t.Logf("Ran %d inner functions", *num)
+	if *value != obj["Value"][0].Value().(int64) {
+		t.Fatalf("value wrong value %d v %d", *value, obj["Value"][0].Value().(int64))
+	}
+}
+
+func TestRaceNonConflictingPuts(t *testing.T) {
+	t.Parallel()
+
+	ds := datastore.Get(Use(context.Background()))
+
+	num := new(int64)

[dnj, 2015/11/10 00:20:20]

int64(0)

+
+	wg := sync.WaitGroup{}
+
+	for i := 0; i < 100; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+
+			err := ds.RunInTransaction(func(c context.Context) error {
+				ds := datastore.Get(c)
+				return ds.Put(pmap(
+					"$kind", "Thing", Next,
+					"Value", 100))
+			}, nil)
+			if err != nil {
+				t.Fatal("error during transaction", err)
+			}
+			atomic.AddInt64(num, 1)
+		}()
+	}
+	wg.Wait()
+
+	if *num != 100 {
+		t.Fatal("expected 100 runs, got", *num)
+	}
+}