Add meta package to datastore.

service/datastore/meta/eg_test.go

Index: service/datastore/meta/eg_test.go
diff --git a/service/datastore/meta/eg_test.go b/service/datastore/meta/eg_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..878a8828769fbd8b7f416c75d15df87f7d54c158
--- /dev/null
+++ b/service/datastore/meta/eg_test.go
@@ -0,0 +1,53 @@
+// 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 meta
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/luci/gae/filter/featureBreaker"
+	"github.com/luci/gae/impl/memory"
+	"github.com/luci/gae/service/datastore"
+	. "github.com/smartystreets/goconvey/convey"
+	"golang.org/x/net/context"
+)
+
+func TestGetEntityGroupVersion(t *testing.T) {
+	t.Parallel()
+
+	Convey("GetEntityGroupVersion", t, func() {
+		c := memory.Use(context.Background())
+		c, fb := featureBreaker.FilterRDS(c, errors.New("INTERNAL_ERROR"))
+		ds := datastore.Get(c)
+
+		pm := datastore.PropertyMap{
+			"$key": {datastore.MkPropertyNI(ds.MakeKey("A", ""))},
+			"Val":  {datastore.MkProperty(10)},
+		}
+		So(ds.Put(pm), ShouldBeNil)
+		aKey := ds.KeyForObj(pm)
+		So(aKey, ShouldNotBeNil)
+
+		v, err := GetEntityGroupVersion(c, aKey)
+		So(err, ShouldBeNil)
+		So(v, ShouldEqual, 1)
+
+		So(ds.Delete(aKey), ShouldBeNil)
+
+		v, err = GetEntityGroupVersion(c, ds.NewKey("madeUp", "thing", 0, aKey))
+		So(err, ShouldBeNil)
+		So(v, ShouldEqual, 2)
+
+		v, err = GetEntityGroupVersion(c, ds.NewKey("madeUp", "thing", 0, nil))
+		So(err, ShouldBeNil)
+		So(v, ShouldEqual, 0)
+
+		fb.BreakFeatures(nil, "GetMulti")
+
+		v, err = GetEntityGroupVersion(c, aKey)
+		So(err.Error(), ShouldContainSubstring, "INTERNAL_ERROR")
+	})
+}