syncthing/lib/sync/sync_test.go

// Copyright (C) 2015 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at http://mozilla.org/MPL/2.0/.

package sync

import (
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/syncthing/syncthing/lib/logger"
)

const (
	logThreshold = 100 * time.Millisecond
	shortWait    = 5 * time.Millisecond
	longWait     = 125 * time.Millisecond
)

var skipTimingTests = false

func init() {
	// Check a few times that a short sleep does not in fact overrun the log
	// threshold. If it does, the timer accuracy is crap or the host is
	// overloaded and we can't reliably run the tests in here. In the normal
	// case this takes just 25*5 = 125 ms.
	for i := 0; i < 25; i++ {
		t0 := time.Now()
		time.Sleep(shortWait)
		if time.Since(t0) > logThreshold {
			skipTimingTests = true
			return
		}
	}
}

func TestTypes(t *testing.T) {
	debug = false
	l.SetDebug("sync", false)

	if _, ok := NewMutex().(*sync.Mutex); !ok {
		t.Error("Wrong type")
	}

	if _, ok := NewRWMutex().(*sync.RWMutex); !ok {
		t.Error("Wrong type")
	}

	if _, ok := NewWaitGroup().(*sync.WaitGroup); !ok {
		t.Error("Wrong type")
	}

	debug = true
	l.SetDebug("sync", true)

	if _, ok := NewMutex().(*loggedMutex); !ok {
		t.Error("Wrong type")
	}

	if _, ok := NewRWMutex().(*loggedRWMutex); !ok {
		t.Error("Wrong type")
	}

	if _, ok := NewWaitGroup().(*loggedWaitGroup); !ok {
		t.Error("Wrong type")
	}

	debug = false
	l.SetDebug("sync", false)
}

func TestMutex(t *testing.T) {
	if skipTimingTests {
		t.Skip("insufficient timer accuracy")
		return
	}

	debug = true
	l.SetDebug("sync", true)
	threshold = logThreshold

	msgmut := sync.Mutex{}
	var messages []string

	l.AddHandler(logger.LevelDebug, func(_ logger.LogLevel, message string) {
		msgmut.Lock()
		messages = append(messages, message)
		msgmut.Unlock()
	})

	mut := NewMutex()
	mut.Lock()
	time.Sleep(shortWait)
	mut.Unlock()

	if len(messages) > 0 {
		t.Errorf("Unexpected message count")
	}

	mut.Lock()
	time.Sleep(longWait)
	mut.Unlock()

	if len(messages) != 1 {
		t.Errorf("Unexpected message count")
	}

	debug = false
	l.SetDebug("sync", false)
}

func TestRWMutex(t *testing.T) {
	if skipTimingTests {
		t.Skip("insufficient timer accuracy")
		return
	}

	debug = true
	l.SetDebug("sync", true)
	threshold = logThreshold

	msgmut := sync.Mutex{}
	var messages []string

	l.AddHandler(logger.LevelDebug, func(_ logger.LogLevel, message string) {
		msgmut.Lock()
		messages = append(messages, message)
		msgmut.Unlock()
	})

	mut := NewRWMutex()
	mut.Lock()
	time.Sleep(shortWait)
	mut.Unlock()

	if len(messages) > 0 {
		t.Errorf("Unexpected message count")
	}

	mut.Lock()
	time.Sleep(longWait)
	mut.Unlock()

	if len(messages) != 1 {
		t.Errorf("Unexpected message count")
	}

	// Testing rlocker logging
	mut.RLock()
	go func() {
		time.Sleep(longWait)
		mut.RUnlock()
	}()

	mut.Lock()
	_ = 1 // skip empty critical section check
	mut.Unlock()

	if len(messages) != 2 {
		t.Errorf("Unexpected message count")
	}
	if !strings.Contains(messages[1], "RUnlockers while locking:\nat sync") || !strings.Contains(messages[1], "sync_test.go:") {
		t.Error("Unexpected message")
	}

	// Testing multiple rlockers
	mut.RLock()
	mut.RLock()
	mut.RLock()
	_ = 1 // skip empty critical section check
	mut.RUnlock()
	mut.RUnlock()
	mut.RUnlock()

	debug = false
	l.SetDebug("sync", false)
}

func TestWaitGroup(t *testing.T) {
	if skipTimingTests {
		t.Skip("insufficient timer accuracy")
		return
	}

	debug = true
	l.SetDebug("sync", true)
	threshold = logThreshold

	msgmut := sync.Mutex{}
	var messages []string

	l.AddHandler(logger.LevelDebug, func(_ logger.LogLevel, message string) {
		msgmut.Lock()
		messages = append(messages, message)
		msgmut.Unlock()
	})

	wg := NewWaitGroup()
	wg.Add(1)
	go func() {
		time.Sleep(shortWait)
		wg.Done()
	}()
	wg.Wait()

	if len(messages) > 0 {
		t.Errorf("Unexpected message count")
	}

	wg = NewWaitGroup()
	wg.Add(1)
	go func() {
		time.Sleep(longWait)
		wg.Done()
	}()
	wg.Wait()

	if len(messages) != 1 {
		t.Errorf("Unexpected message count")
	}

	debug = false
	l.SetDebug("sync", false)
}