Add ability to estimate the size of a PropertyMap

service/datastore/size_test.go

Index: service/datastore/size_test.go
diff --git a/service/datastore/size_test.go b/service/datastore/size_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..3279948977a27889d68a2f53ac24f8262eefcbdf
--- /dev/null
+++ b/service/datastore/size_test.go
@@ -0,0 +1,80 @@
+// 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 datastore
+
+import (
+	"bytes"
+	"fmt"
+	"sort"
+	"strings"
+	"testing"
+
+	"github.com/luci/gae/service/blobstore"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func mps(vals ...interface{}) PropertySlice {
+	ret := make(PropertySlice, len(vals))
+	for i, val := range vals {
+		ret[i] = mp(val)
+	}
+	return ret
+}
+
+var estimateSizeTests = []struct {
+	pm     PropertyMap
+	expect int
+}{
+	{PropertyMap{"Something": {}}, 9},
+	{PropertyMap{"Something": mps(100)}, 18},
+	{PropertyMap{"Something": mps(100.1, "sup")}, 22},
+	{PropertyMap{
+		"Something": mps(100, "sup"),
+		"Keys":      mps(MakeKey("aid", "ns", "parent", "something", "kind", int64(20))),
+	}, 59},
+	{PropertyMap{
+		"Null":   mps(nil),
+		"Bool":   mps(true, false),
+		"GP":     mps(GeoPoint{23.2, 122.1}),
+		"bskey":  mps(blobstore.Key("hello")),
+		"[]byte": mps([]byte("sup")),
+	}, 59},
+}
+
+func stablePmString(pm PropertyMap) string {
+	keys := make([]string, 0, len(pm))
+	for k := range pm {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+
+	buf := &bytes.Buffer{}
+	_, _ = buf.WriteString("map[")
+	for i, k := range keys {
+		if i != 0 {
+			_, _ = buf.WriteString(" ")
+		}
+		vals := pm[k]
+		strs := make([]string, len(vals))
+		for i, v := range vals {
+			strs[i] = v.GQL()
+		}
+		fmt.Fprintf(buf, "%s:[%s]", k, strings.Join(strs, ", "))
+	}
+	_, _ = buf.WriteRune(']')
+	return buf.String()
+}
+
+func TestEstimateSizes(t *testing.T) {
+	t.Parallel()
+
+	Convey("Test EstimateSize", t, func() {
+		for _, tc := range estimateSizeTests {
+			Convey(stablePmString(tc.pm), func() {
+				So(tc.pm.EstimateSize(), ShouldEqual, tc.expect)
+			})
+		}
+	})
+}