-
Notifications
You must be signed in to change notification settings - Fork 0
/
cond_test.go
193 lines (161 loc) · 3.1 KB
/
cond_test.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
package sync
import (
"context"
"sync"
"testing"
)
func newTestCond() *Cond {
// using stdlib to not have to debug two things at the same time.
var m sync.Mutex
return NewCond(&m)
}
func TestCondBasicSignal(t *testing.T) {
c := newTestCond()
c.L.Lock()
c.Signal()
c.L.Unlock()
}
func TestCondBasicBroadcast(t *testing.T) {
c := newTestCond()
c.L.Lock()
c.Broadcast()
c.L.Unlock()
}
func TestBasicCondSignal(t *testing.T) {
c := newTestCond()
var waiterdone sync.WaitGroup
var waiterstarted sync.WaitGroup
waiterdone.Add(1)
waiterstarted.Add(1)
go func() {
c.L.Lock()
waiterstarted.Done()
c.Wait()
c.L.Unlock()
waiterdone.Done()
}()
waiterstarted.Wait()
c.L.Lock()
c.Signal()
c.L.Unlock()
waiterdone.Wait()
}
func TestBasicCondBroadcast(t *testing.T) {
nthreads := 4
c := newTestCond()
var waitersdone sync.WaitGroup
var waitersstarted sync.WaitGroup
waitersdone.Add(nthreads)
waitersstarted.Add(nthreads)
f := func() {
c.L.Lock()
waitersstarted.Done()
c.Wait()
c.L.Unlock()
waitersdone.Done()
}
for i := 0; i < nthreads; i++ {
go f()
}
waitersstarted.Wait()
c.L.Lock()
c.Broadcast()
c.L.Unlock()
waitersdone.Wait()
}
func TestCondWaitDeadline(t *testing.T) {
c := newTestCond()
c.L.Lock()
defer c.L.Unlock()
ctx, cancel := context.WithCancel(context.Background())
cancel()
err := c.WaitWithContext(ctx)
if expected := context.Canceled; err != expected {
t.Error("unexpected error. was:", err, "expected:", expected)
}
}
// TestForCondRaceConditions is a catch-all test that makes sure we don't
// deadlock in some weird edge case.
func TestCondSignal(t *testing.T) {
c := newTestCond()
nthreads := 2
started := make(chan struct{})
awake := make(chan struct{}, nthreads)
var wg sync.WaitGroup
for i := 0; i < nthreads; i++ {
wg.Add(1)
go func() {
c.L.Lock()
started <- struct{}{}
c.Wait()
awake <- struct{}{}
c.L.Unlock()
wg.Done()
}()
}
for i := 0; i < nthreads; i++ {
<-started
}
// All threads are now in a waiting state.
for i := 0; i < nthreads; i++ {
select {
case <-awake:
t.Fatal("at least one goroutine is not asleep")
default:
}
c.L.Lock()
c.Signal()
c.L.Unlock()
<-awake // Will deadlock if no goroutine wakes up
select {
case <-awake:
t.Fatal("unexpected goroutines awake")
default:
}
}
wg.Wait()
}
func TestCondBroadcast(t *testing.T) {
c := newTestCond()
nthreads := 200
started := make(chan int, nthreads)
awake := make(chan int, nthreads)
var wg sync.WaitGroup
for i := 0; i < nthreads; i++ {
wg.Add(1)
go func(g int) {
c.L.Lock()
started <- g
c.Wait()
awake <- g
c.L.Unlock()
wg.Done()
}(i)
}
for i := 0; i < nthreads; i++ {
<-started
}
// nthreads goroutines are now running
select {
case <-awake:
t.Fatal("at least one goroutine is not asleep")
default:
}
c.L.Lock()
c.Broadcast()
c.L.Unlock()
seen := make([]bool, nthreads)
for i := 0; i < nthreads; i++ {
g := <-awake
if seen[g] {
t.Fatal("goroutine woke up twice")
}
seen[g] = true
}
select {
case <-started:
t.Fatal("goroutine did not exit")
default:
}
wg.Wait()
}