Add emulation of transaction retries to memory impl of RunInTransaction.

impl/memory/datastore_query_execution_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 memory
 
 import (
         "fmt"
         "testing"
         "time"
@@ skipping 293 matching lines @@
 func TestQueryExecution(t *testing.T) {
         t.Parallel()
 
         Convey("Test query execution", t, func() {
                 c, err := info.Get(Use(context.Background())).Namespace("ns")
                 if err != nil {
                         panic(err)
                 }
 
                 data := ds.Get(c)
-                testing := data.Raw().Testable()
+                testing := data.Testable()
 
                 for _, tc := range queryExecutionTests {
                         Convey(tc.name, func() {
                                 for i, stage := range tc.test {
                                         // outside of Convey, since these must always happen
                                         testing.CatchupIndexes()
 
                                         testing.AddIndexes(stage.addIdxs...)
                                         if err := data.PutMulti(stage.putEnts); err != nil {
                                                 // prevent Convey from thinking this assertion should show up in
@@ skipping 48 matching lines @@
                                                         Convey(fmt.Sprintf("extraFn %d", j), func() {
                                                                 fn(c)
                                                         })
                                                 }
                                         })
                                 }
                         })
                 }
         })
 }