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package ctxwatch_test
import (
"context"
"sync/atomic"
"testing"
"time"
"github.com/jackc/pgconn/internal/ctxwatch"
"github.com/stretchr/testify/require"
)
func TestContextWatcherContextCancelled(t *testing.T) {
canceledChan := make(chan struct{})
cleanupCalled := false
cw := ctxwatch.NewContextWatcher(func() {
canceledChan <- struct{}{}
}, func() {
cleanupCalled = true
})
ctx, cancel := context.WithCancel(context.Background())
cw.Watch(ctx)
cancel()
select {
case <-canceledChan:
case <-time.NewTimer(time.Second).C:
t.Fatal("Timed out waiting for cancel func to be called")
}
cw.Unwatch()
require.True(t, cleanupCalled, "Cleanup func was not called")
}
func TestContextWatcherUnwatchdBeforeContextCancelled(t *testing.T) {
cw := ctxwatch.NewContextWatcher(func() {
t.Error("cancel func should not have been called")
}, func() {
t.Error("cleanup func should not have been called")
})
ctx, cancel := context.WithCancel(context.Background())
cw.Watch(ctx)
cw.Unwatch()
cancel()
}
func TestContextWatcherMultipleWatchPanics(t *testing.T) {
cw := ctxwatch.NewContextWatcher(func() {}, func() {})
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
cw.Watch(ctx)
ctx2, cancel2 := context.WithCancel(context.Background())
defer cancel2()
require.Panics(t, func() { cw.Watch(ctx2) }, "Expected panic when Watch called multiple times")
}
func TestContextWatcherUnwatchWhenNotWatchingIsSafe(t *testing.T) {
cw := ctxwatch.NewContextWatcher(func() {}, func() {})
cw.Unwatch() // unwatch when not / never watching
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
cw.Watch(ctx)
cw.Unwatch()
cw.Unwatch() // double unwatch
}
func TestContextWatcherUnwatchIsConcurrencySafe(t *testing.T) {
cw := ctxwatch.NewContextWatcher(func() {}, func() {})
ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
defer cancel()
cw.Watch(ctx)
go cw.Unwatch()
go cw.Unwatch()
<-ctx.Done()
}
func TestContextWatcherStress(t *testing.T) {
var cancelFuncCalls int64
var cleanupFuncCalls int64
cw := ctxwatch.NewContextWatcher(func() {
atomic.AddInt64(&cancelFuncCalls, 1)
}, func() {
atomic.AddInt64(&cleanupFuncCalls, 1)
})
cycleCount := 100000
for i := 0; i < cycleCount; i++ {
ctx, cancel := context.WithCancel(context.Background())
cw.Watch(ctx)
if i%2 == 0 {
cancel()
}
// Without time.Sleep, cw.Unwatch will almost always run before the cancel func which means cancel will never happen. This gives us a better mix.
if i%3 == 0 {
time.Sleep(time.Nanosecond)
}
cw.Unwatch()
if i%2 == 1 {
cancel()
}
}
actualCancelFuncCalls := atomic.LoadInt64(&cancelFuncCalls)
actualCleanupFuncCalls := atomic.LoadInt64(&cleanupFuncCalls)
if actualCancelFuncCalls == 0 {
t.Fatal("actualCancelFuncCalls == 0")
}
maxCancelFuncCalls := int64(cycleCount) / 2
if actualCancelFuncCalls > maxCancelFuncCalls {
t.Errorf("cancel func calls should be no more than %d but was %d", actualCancelFuncCalls, maxCancelFuncCalls)
}
if actualCancelFuncCalls != actualCleanupFuncCalls {
t.Errorf("cancel func calls (%d) should be equal to cleanup func calls (%d) but was not", actualCancelFuncCalls, actualCleanupFuncCalls)
}
}
func BenchmarkContextWatcherUncancellable(b *testing.B) {
cw := ctxwatch.NewContextWatcher(func() {}, func() {})
for i := 0; i < b.N; i++ {
cw.Watch(context.Background())
cw.Unwatch()
}
}
func BenchmarkContextWatcherCancelled(b *testing.B) {
cw := ctxwatch.NewContextWatcher(func() {}, func() {})
for i := 0; i < b.N; i++ {
ctx, cancel := context.WithCancel(context.Background())
cw.Watch(ctx)
cancel()
cw.Unwatch()
}
}
func BenchmarkContextWatcherCancellable(b *testing.B) {
cw := ctxwatch.NewContextWatcher(func() {}, func() {})
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
for i := 0; i < b.N; i++ {
cw.Watch(ctx)
cw.Unwatch()
}
}
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