github.com/likebike/go--@v0.0.0-20190911215757-0bd925d16e96/go/src/runtime/race/testdata/sync_test.go

// Copyright 2011 The Go 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 race_test

import (
	"sync"
	"testing"
	"time"
)

func TestNoRaceCond(t *testing.T) {
	x := 0
	_ = x
	condition := 0
	var mu sync.Mutex
	cond := sync.NewCond(&mu)
	go func() {
		x = 1
		mu.Lock()
		condition = 1
		cond.Signal()
		mu.Unlock()
	}()
	mu.Lock()
	for condition != 1 {
		cond.Wait()
	}
	mu.Unlock()
	x = 2
}

func TestRaceCond(t *testing.T) {
	done := make(chan bool)
	var mu sync.Mutex
	cond := sync.NewCond(&mu)
	x := 0
	_ = x
	condition := 0
	go func() {
		time.Sleep(10 * time.Millisecond) // Enter cond.Wait loop
		x = 1
		mu.Lock()
		condition = 1
		cond.Signal()
		mu.Unlock()
		time.Sleep(10 * time.Millisecond) // Exit cond.Wait loop
		mu.Lock()
		x = 3
		mu.Unlock()
		done <- true
	}()
	mu.Lock()
	for condition != 1 {
		cond.Wait()
	}
	mu.Unlock()
	x = 2
	<-done
}

// We do not currently automatically
// parse this test. It is intended that the creation
// stack is observed manually not to contain
// off-by-one errors
func TestRaceAnnounceThreads(t *testing.T) {
	const N = 7
	allDone := make(chan bool, N)

	var x int
	_ = x

	var f, g, h func()
	f = func() {
		x = 1
		go g()
		go func() {
			x = 1
			allDone <- true
		}()
		x = 2
		allDone <- true
	}

	g = func() {
		for i := 0; i < 2; i++ {
			go func() {
				x = 1
				allDone <- true
			}()
			allDone <- true
		}
	}

	h = func() {
		x = 1
		x = 2
		go f()
		allDone <- true
	}

	go h()

	for i := 0; i < N; i++ {
		<-allDone
	}
}

func TestNoRaceAfterFunc1(t *testing.T) {
	i := 2
	c := make(chan bool)
	var f func()
	f = func() {
		i--
		if i >= 0 {
			time.AfterFunc(0, f)
		} else {
			c <- true
		}
	}

	time.AfterFunc(0, f)
	<-c
}

func TestNoRaceAfterFunc2(t *testing.T) {
	var x int
	timer := time.AfterFunc(10, func() {
		x = 1
	})
	defer timer.Stop()
	_ = x
}

func TestNoRaceAfterFunc3(t *testing.T) {
	c := make(chan bool, 1)
	x := 0
	_ = x
	time.AfterFunc(1e7, func() {
		x = 1
		c <- true
	})
	<-c
}

func TestRaceAfterFunc3(t *testing.T) {
	c := make(chan bool, 2)
	x := 0
	_ = x
	time.AfterFunc(1e7, func() {
		x = 1
		c <- true
	})
	time.AfterFunc(2e7, func() {
		x = 2
		c <- true
	})
	<-c
	<-c
}

// This test's output is intended to be
// observed manually. One should check
// that goroutine creation stack is
// comprehensible.
func TestRaceGoroutineCreationStack(t *testing.T) {
	var x int
	_ = x
	var ch = make(chan bool, 1)

	f1 := func() {
		x = 1
		ch <- true
	}
	f2 := func() { go f1() }
	f3 := func() { go f2() }
	f4 := func() { go f3() }

	go f4()
	x = 2
	<-ch
}

// A nil pointer in a mutex method call should not
// corrupt the race detector state.
// Used to hang indefinitely.
func TestNoRaceNilMutexCrash(t *testing.T) {
	var mutex sync.Mutex
	panics := 0
	defer func() {
		if x := recover(); x != nil {
			mutex.Lock()
			panics++
			mutex.Unlock()
		} else {
			panic("no panic")
		}
	}()
	var othermutex *sync.RWMutex
	othermutex.RLock()
}