logdog: Add bundler library.

client/internal/logdog/butler/bundler/sizer_fast_test.go

Index: client/internal/logdog/butler/bundler/sizer_fast_test.go
diff --git a/client/internal/logdog/butler/bundler/sizer_fast_test.go b/client/internal/logdog/butler/bundler/sizer_fast_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..9ec38cb576a8fa3128e740dc56e745a5a0c1e799
--- /dev/null
+++ b/client/internal/logdog/butler/bundler/sizer_fast_test.go
@@ -0,0 +1,122 @@
+// 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 bundler
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/golang/protobuf/proto"
+	"github.com/luci/luci-go/common/logdog/protocol"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+// A proto.Message implementation with test fields.
+type testMessage struct {
+	U64 *uint64 `protobuf:"varint,1,opt,name=u64"`
+}
+
+func (t *testMessage) Reset()         {}
+func (t *testMessage) String() string { return "" }
+func (t *testMessage) ProtoMessage()  {}
+
+func TestFastSizerVarintLength(t *testing.T) {
+	Convey(`A test message`, t, func() {
+		for _, threshold := range []uint64{
+			0,
+			0x80,
+			0x4000,
+			0x200000,
+			0x100000000,
+			0x800000000,
+			0x40000000000,
+			0x2000000000000,
+			0x100000000000000,
+			0x8000000000000000,
+		} {
+
+			for _, delta := range []int64{
+				-2,
+				-1,
+				0,
+				1,
+				2,
+			} {
+				// Add "delta" to "threshold" in a uint64-aware manner.
+				u64 := threshold
+				if delta >= 0 {
+					u64 += uint64(delta)
+				} else {
+					if u64 < uint64(-delta) {
+						continue
+					}
+					u64 -= uint64(-delta)
+				}
+
+				expected := varintLength(u64)
+				Convey(fmt.Sprintf(`Testing threshold 0x%x should encode to varint size %d`, u64, expected), func() {
+					m := &testMessage{
+						U64: &u64,
+					}
+					// Note: "-1" is for the "U64" field tag, "1", which has encoded size of 1.
+					So(expected, ShouldEqual, proto.Size(m)-1)
+				})
+			}
+		}
+	})
+}
+
+func TestFastSizer(t *testing.T) {
+	Convey(`A fastSizer instance`, t, func() {
+		source := "test source"
+		u64 := uint64(0x1337d06)
+		bundle := &protocol.ButlerLogBundle{
+			Source: &source,
+			Timestamp: &protocol.Timestamp{
+				UsFromEpoch: &u64,
+			},
+		}
+		s := NewFastSizer(bundle)
+		initSize := s.Size()
+
+		Convey(`Has a valid initial size.`, func() {
+			So(initSize, ShouldEqual, proto.Size(bundle))
+		})
+
+		Convey(`After appending a bundle entry`, func() {
+			be := &protocol.ButlerLogBundle_Entry{
+				Secret: bytes.Repeat([]byte{0x55, 0xAA}, 16),
+			}
+			s.AppendBundleEntry(be)
+			bundle.Entries = append(bundle.Entries, be)
+			So(s.Size(), ShouldEqual, proto.Size(bundle))
+
+			Convey(`After appending log entries`, func() {
+				for i := 0; i < 10; i++ {
+					log := &protocol.LogEntry{
+						Lines: []string{
+							strings.Repeat("A", i*10),
+							strings.Repeat("B", i*20),
+						},
+						Data: [][]byte{
+							bytes.Repeat([]byte{0x55, 0xAA}, i*10),
+							bytes.Repeat([]byte{0x10, 0x6d, 0x06}, i*20),
+						},
+					}
+
+					s.AppendLogEntry(be, log)
+					be.Logs = append(be.Logs, log)
+					So(s.Size(), ShouldEqual, proto.Size(bundle))
+				}
+
+				Convey(`Whole bundle should equal the actual protobuf size.`, func() {
+					So(s.Size(), ShouldEqual, proto.Size(bundle))
+				})
+			})
+		})
+	})
+}