From a9fe30626a85a966ff6259b6e7ea56fd11895c6d Mon Sep 17 00:00:00 2001
From: Martin Hutchinson <mhutchinson@gmail.com>
Date: Wed, 14 Aug 2024 14:08:16 +0100
Subject: [PATCH] Tests for the hammer analysis (#137)

Basic tests to make sure that the average reported is correct and that async behaviour is reliable.

Both the test and the analysis code under test had race unsafe code, which is now fixed.
---
 hammer/hammer.go      | 35 ++++++++++++----------
 hammer/hammer_test.go | 67 +++++++++++++++++++++++++++++++++++++++++++
 hammer/tui.go         |  2 +-
 3 files changed, 88 insertions(+), 16 deletions(-)
 create mode 100644 hammer/hammer_test.go

diff --git a/hammer/hammer.go b/hammer/hammer.go
index c0fe4ef8..dfa0fbd3 100644
--- a/hammer/hammer.go
+++ b/hammer/hammer.go
@@ -89,7 +89,7 @@ func main() {
 		klog.Exitf("Failed to get initial state of the log: %v", err)
 	}
 
-	ha := newHammerAnalyser(&tracker, 100)
+	ha := newHammerAnalyser(func() uint64 { return tracker.LatestConsistent.Size })
 	go ha.updateStatsLoop(ctx)
 	go ha.errorLoop(ctx)
 
@@ -181,38 +181,38 @@ func (h *Hammer) updateCheckpointLoop(ctx context.Context) {
 	}
 }
 
-func newHammerAnalyser(tracker *client.LogStateTracker, chanSize int) *HammerAnalyser {
-	leafSampleChan := make(chan leafTime, chanSize)
+func newHammerAnalyser(treeSizeFn func() uint64) *HammerAnalyser {
+	leafSampleChan := make(chan leafTime, 100)
 	errChan := make(chan error, 20)
 	return &HammerAnalyser{
-		tracker:         tracker,
+		treeSizeFn:      treeSizeFn,
 		seqLeafChan:     leafSampleChan,
 		errChan:         errChan,
-		integrationTime: movingaverage.New(30),
-		queueTime:       movingaverage.New(30),
+		integrationTime: movingaverage.Concurrent(movingaverage.New(30)),
+		queueTime:       movingaverage.Concurrent(movingaverage.New(30)),
 	}
 }
 
 // HammerAnalyser is responsible for measuring and interpreting the result of hammering.
 type HammerAnalyser struct {
-	tracker     *client.LogStateTracker
+	treeSizeFn  func() uint64
 	seqLeafChan chan leafTime
 	errChan     chan error
 
-	queueTime       *movingaverage.MovingAverage
-	integrationTime *movingaverage.MovingAverage
+	queueTime       *movingaverage.ConcurrentMovingAverage
+	integrationTime *movingaverage.ConcurrentMovingAverage
 }
 
 func (a *HammerAnalyser) updateStatsLoop(ctx context.Context) {
 	tick := time.NewTicker(100 * time.Millisecond)
-	size := a.tracker.LatestConsistent.Size
+	size := a.treeSizeFn()
 	for {
 		select {
 		case <-ctx.Done():
 			return
 		case <-tick.C:
 		}
-		newSize := a.tracker.LatestConsistent.Size
+		newSize := a.treeSizeFn()
 		if newSize <= size {
 			continue
 		}
@@ -221,13 +221,18 @@ func (a *HammerAnalyser) updateStatsLoop(ctx context.Context) {
 		queueLatency := time.Duration(0)
 		numLeaves := 0
 		var sample *leafTime
+	ReadLoop:
 		for {
 			if sample == nil {
-				l, ok := <-a.seqLeafChan
-				if !ok {
-					break
+				select {
+				case l, ok := <-a.seqLeafChan:
+					if !ok {
+						break ReadLoop
+					}
+					sample = &l
+				default:
+					break ReadLoop
 				}
-				sample = &l
 			}
 			// Stop considering leaf times once we've caught up with that cross
 			// either the current checkpoint or "now":
diff --git a/hammer/hammer_test.go b/hammer/hammer_test.go
new file mode 100644
index 00000000..25941fe0
--- /dev/null
+++ b/hammer/hammer_test.go
@@ -0,0 +1,67 @@
+// Copyright 2024 The Tessera authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"context"
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestHammerAnalyser_Stats(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	var treeSize treeSizeState
+	ha := newHammerAnalyser(treeSize.getSize)
+
+	go ha.updateStatsLoop(ctx)
+
+	time.Sleep(100 * time.Millisecond)
+
+	baseTime := time.Now().Add(-1 * time.Minute)
+	for i := 0; i < 10; i++ {
+		ha.seqLeafChan <- leafTime{
+			idx:        uint64(i),
+			queuedAt:   baseTime,
+			assignedAt: baseTime.Add(time.Duration(i) * time.Second),
+		}
+	}
+	treeSize.setSize(10)
+	time.Sleep(500 * time.Millisecond)
+
+	avg := ha.queueTime.Avg()
+	if want := float64(4500); avg != want {
+		t.Errorf("integration time avg: got != want (%f != %f)", avg, want)
+	}
+}
+
+type treeSizeState struct {
+	size uint64
+	mux  sync.RWMutex
+}
+
+func (s *treeSizeState) getSize() uint64 {
+	s.mux.RLock()
+	defer s.mux.RUnlock()
+	return s.size
+}
+
+func (s *treeSizeState) setSize(size uint64) {
+	s.mux.Lock()
+	defer s.mux.Unlock()
+	s.size = size
+}
diff --git a/hammer/tui.go b/hammer/tui.go
index eb1c77bc..c7d9ace1 100644
--- a/hammer/tui.go
+++ b/hammer/tui.go
@@ -112,7 +112,7 @@ func (c *tuiController) Run(ctx context.Context) {
 }
 
 func (c *tuiController) updateStatsLoop(ctx context.Context, interval time.Duration) {
-	formatMovingAverage := func(ma *movingaverage.MovingAverage) string {
+	formatMovingAverage := func(ma *movingaverage.ConcurrentMovingAverage) string {
 		aMin, _ := ma.Min()
 		aMax, _ := ma.Max()
 		aAvg := ma.Avg()