syncthing/lib/sync/sync_test.go
2017-02-09 08:04:16 +01:00

326 lines
6.6 KiB
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 https://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)
}
func TestTimeoutCond(t *testing.T) {
// WARNING this test relies heavily on threads not being stalled at particular points.
// As such, it's pretty unstable on the build server. It has been left in as it still
// exercises the deadlock detector, and one of the two things it tests is still functional.
// See the comments in runLocks
const (
// Low values to avoid being intrusive in continuous testing. Can be
// increased significantly for stress testing.
iterations = 100
routines = 10
timeMult = 2
)
c := NewTimeoutCond(NewMutex())
// Start a routine to periodically broadcast on the cond.
go func() {
d := time.Duration(routines) * timeMult * time.Millisecond / 2
t.Log("Broadcasting every", d)
for i := 0; i < iterations; i++ {
time.Sleep(d)
c.L.Lock()
c.Broadcast()
c.L.Unlock()
}
}()
// Start several routines that wait on it with different timeouts.
var results [routines][2]int
var wg sync.WaitGroup
for i := 0; i < routines; i++ {
i := i
wg.Add(1)
go func() {
d := time.Duration(i) * timeMult * time.Millisecond
t.Logf("Routine %d waits for %v\n", i, d)
succ, fail := runLocks(t, iterations, c, d)
results[i][0] = succ
results[i][1] = fail
wg.Done()
}()
}
wg.Wait()
// Print a table of routine number: successes, failures.
for i, v := range results {
t.Logf("%4d: %4d %4d\n", i, v[0], v[1])
}
}
func runLocks(t *testing.T, iterations int, c *TimeoutCond, d time.Duration) (succ, fail int) {
for i := 0; i < iterations; i++ {
c.L.Lock()
// The thread may be stalled, so we can't test the 'succeeded late' case reliably.
// Therefore make sure that we start t0 before starting the timeout, and only test
// the 'failed early' case.
t0 := time.Now()
w := c.SetupWait(d)
res := w.Wait()
waited := time.Since(t0)
// Allow 20% slide in either direction, and a five milliseconds of
// scheduling delay... In tweaking these it was clear that things
// worked like the should, so if this becomes a spurious failure
// kind of thing feel free to remove or give significantly more
// slack.
if !res && waited < d*8/10 {
t.Errorf("Wait failed early, %v < %v", waited, d)
}
if res && waited > d*11/10+5*time.Millisecond {
// Ideally this would be t.Errorf
t.Logf("WARNING: Wait succeeded late, %v > %v. This is probably a thread scheduling issue", waited, d)
}
w.Stop()
if res {
succ++
} else {
fail++
}
c.L.Unlock()
}
return
}