+++ /dev/null
-// Copyright 2017 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 semaphore_test
-
-import (
- "context"
- "math/rand"
- "runtime"
- "sync"
- "testing"
- "time"
-
- "golang.org/x/sync/errgroup"
- "golang.org/x/sync/semaphore"
-)
-
-const maxSleep = 1 * time.Millisecond
-
-func HammerWeighted(sem *semaphore.Weighted, n int64, loops int) {
- for i := 0; i < loops; i++ {
- sem.Acquire(context.Background(), n)
- time.Sleep(time.Duration(rand.Int63n(int64(maxSleep/time.Nanosecond))) * time.Nanosecond)
- sem.Release(n)
- }
-}
-
-func TestWeighted(t *testing.T) {
- t.Parallel()
-
- n := runtime.GOMAXPROCS(0)
- loops := 10000 / n
- sem := semaphore.NewWeighted(int64(n))
- var wg sync.WaitGroup
- wg.Add(n)
- for i := 0; i < n; i++ {
- i := i
- go func() {
- defer wg.Done()
- HammerWeighted(sem, int64(i), loops)
- }()
- }
- wg.Wait()
-}
-
-func TestWeightedPanic(t *testing.T) {
- t.Parallel()
-
- defer func() {
- if recover() == nil {
- t.Fatal("release of an unacquired weighted semaphore did not panic")
- }
- }()
- w := semaphore.NewWeighted(1)
- w.Release(1)
-}
-
-func TestWeightedTryAcquire(t *testing.T) {
- t.Parallel()
-
- ctx := context.Background()
- sem := semaphore.NewWeighted(2)
- tries := []bool{}
- sem.Acquire(ctx, 1)
- tries = append(tries, sem.TryAcquire(1))
- tries = append(tries, sem.TryAcquire(1))
-
- sem.Release(2)
-
- tries = append(tries, sem.TryAcquire(1))
- sem.Acquire(ctx, 1)
- tries = append(tries, sem.TryAcquire(1))
-
- want := []bool{true, false, true, false}
- for i := range tries {
- if tries[i] != want[i] {
- t.Errorf("tries[%d]: got %t, want %t", i, tries[i], want[i])
- }
- }
-}
-
-func TestWeightedAcquire(t *testing.T) {
- t.Parallel()
-
- ctx := context.Background()
- sem := semaphore.NewWeighted(2)
- tryAcquire := func(n int64) bool {
- ctx, cancel := context.WithTimeout(ctx, 10*time.Millisecond)
- defer cancel()
- return sem.Acquire(ctx, n) == nil
- }
-
- tries := []bool{}
- sem.Acquire(ctx, 1)
- tries = append(tries, tryAcquire(1))
- tries = append(tries, tryAcquire(1))
-
- sem.Release(2)
-
- tries = append(tries, tryAcquire(1))
- sem.Acquire(ctx, 1)
- tries = append(tries, tryAcquire(1))
-
- want := []bool{true, false, true, false}
- for i := range tries {
- if tries[i] != want[i] {
- t.Errorf("tries[%d]: got %t, want %t", i, tries[i], want[i])
- }
- }
-}
-
-func TestWeightedDoesntBlockIfTooBig(t *testing.T) {
- t.Parallel()
-
- const n = 2
- sem := semaphore.NewWeighted(n)
- {
- ctx, cancel := context.WithCancel(context.Background())
- defer cancel()
- go sem.Acquire(ctx, n+1)
- }
-
- g, ctx := errgroup.WithContext(context.Background())
- for i := n * 3; i > 0; i-- {
- g.Go(func() error {
- err := sem.Acquire(ctx, 1)
- if err == nil {
- time.Sleep(1 * time.Millisecond)
- sem.Release(1)
- }
- return err
- })
- }
- if err := g.Wait(); err != nil {
- t.Errorf("semaphore.NewWeighted(%v) failed to AcquireCtx(_, 1) with AcquireCtx(_, %v) pending", n, n+1)
- }
-}
-
-// TestLargeAcquireDoesntStarve times out if a large call to Acquire starves.
-// Merely returning from the test function indicates success.
-func TestLargeAcquireDoesntStarve(t *testing.T) {
- t.Parallel()
-
- ctx := context.Background()
- n := int64(runtime.GOMAXPROCS(0))
- sem := semaphore.NewWeighted(n)
- running := true
-
- var wg sync.WaitGroup
- wg.Add(int(n))
- for i := n; i > 0; i-- {
- sem.Acquire(ctx, 1)
- go func() {
- defer func() {
- sem.Release(1)
- wg.Done()
- }()
- for running {
- time.Sleep(1 * time.Millisecond)
- sem.Release(1)
- sem.Acquire(ctx, 1)
- }
- }()
- }
-
- sem.Acquire(ctx, n)
- running = false
- sem.Release(n)
- wg.Wait()
-}
-
-// translated from https://github.com/zhiqiangxu/util/blob/master/mutex/crwmutex_test.go#L43
-func TestAllocCancelDoesntStarve(t *testing.T) {
- sem := semaphore.NewWeighted(10)
-
- // Block off a portion of the semaphore so that Acquire(_, 10) can eventually succeed.
- sem.Acquire(context.Background(), 1)
-
- // In the background, Acquire(_, 10).
- ctx, cancel := context.WithCancel(context.Background())
- defer cancel()
- go func() {
- sem.Acquire(ctx, 10)
- }()
-
- // Wait until the Acquire(_, 10) call blocks.
- for sem.TryAcquire(1) {
- sem.Release(1)
- runtime.Gosched()
- }
-
- // Now try to grab a read lock, and simultaneously unblock the Acquire(_, 10) call.
- // Both Acquire calls should unblock and return, in either order.
- go cancel()
-
- err := sem.Acquire(context.Background(), 1)
- if err != nil {
- t.Fatalf("Acquire(_, 1) failed unexpectedly: %v", err)
- }
- sem.Release(1)
-}
projects / dotfiles / .git / blobdiff