Remove SetFinalizer from impl/memory.

impl/memory/datastore_test.go

Index: impl/memory/datastore_test.go
diff --git a/impl/memory/datastore_test.go b/impl/memory/datastore_test.go
index c9580f0f7f1af8cad4585884b1ab52948557a426..529494159ef574f6bb30ad672d63cc08cae1bc73 100644
--- a/impl/memory/datastore_test.go
+++ b/impl/memory/datastore_test.go
@@ -6,7 +6,9 @@ package memory
 
 import (
 	"errors"
+	"flag"
 	"fmt"
+	"runtime"
 	"testing"
 	"time"
 
@@ -20,6 +22,8 @@ import (
 	. "github.com/smartystreets/goconvey/convey"
 )
 
+var enableMemoryTest = flag.Bool("test.memusage", false, "Enable memory usage test.")
+
 type MetaGroup struct {
 	_id    int64   `gae:"$id,1"`
 	_kind  string  `gae:"$kind,__entity_group__"`
@@ -815,3 +819,55 @@ func TestAddIndexes(t *testing.T) {
 		})
 	})
 }
+
+// TestMemoryUsage performs a series of datastore operations, profiling the
+// memory usage before and after.
+//
+// This is an expensive test, and it's not really sufficiently deterministic to
+// be enabled by default. If you want to run this, use the '-test.memusage'
+// flag.
+func TestMemoryUsage(t *testing.T) {
+	if !*enableMemoryTest {
+		return
+	}
+
+	Convey("A datastore instance does not leak memory.", t, func() {
+		const rounds, items = 10, 200
+
+		// Initial memory stats.
+		var ms runtime.MemStats
+		runtime.MemProfileRate = 1
+		runtime.GC()
+		runtime.ReadMemStats(&ms)
+		initialAlloc := ms.Alloc
+
+		// Run the memory test entirely within its own function scope. This will
+		// provide a hard boundary where all associated resources should be
+		// free-able.
+		func() {
+			c := Use(context.Background())
+			for i := 0; i < rounds; i++ {
+				toPut := make([]ds.PropertyMap, items)
+				for j := range toPut {
+					toPut[j] = ds.PropertyMap{
+						"$kind": ds.MkProperty(fmt.Sprintf("kind-%d", j)),
+						"$id":   ds.MkProperty(1),
+					}
+				}
+				if err := ds.Put(c, toPut); err != nil {
+					panic(err)
+				}
+
+				runtime.GC()
+			}
+		}()
+
+		for i := 0; i < 3; i++ {
+			time.Sleep(100 * time.Millisecond)
+			runtime.GC()
+		}
+		runtime.ReadMemStats(&ms)
+
+		t.Logf("Memory alloc difference is: %d", ms.Alloc-initialAlloc)
+	})
+}