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PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 93 insertions, 0 deletions

diff --git a/pkg/amutex/amutex_test.go b/pkg/amutex/amutex_test.go
new file mode 100644
index 000000000..876e47b19
--- /dev/null
+++ b/pkg/amutex/amutex_test.go
@@ -0,0 +1,93 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package amutex
+
+import (
+	"sync"
+	"testing"
+	"time"
+)
+
+type sleeper struct {
+	ch chan struct{}
+}
+
+func (s *sleeper) SleepStart() <-chan struct{} {
+	return s.ch
+}
+
+func (*sleeper) SleepFinish(bool) {
+}
+
+func TestMutualExclusion(t *testing.T) {
+	var m AbortableMutex
+	m.Init()
+
+	// Test mutual exclusion by running "gr" goroutines concurrently, and
+	// have each one increment a counter "iters" times within the critical
+	// section established by the mutex.
+	//
+	// If at the end of the counter is not gr * iters, then we know that
+	// goroutines ran concurrently within the critical section.
+	//
+	// If one of the goroutines doesn't complete, it's likely a bug that
+	// causes to to wait forever.
+	const gr = 1000
+	const iters = 100000
+	v := 0
+	var wg sync.WaitGroup
+	for i := 0; i < gr; i++ {
+		wg.Add(1)
+		go func() {
+			for j := 0; j < iters; j++ {
+				m.Lock(nil)
+				v++
+				m.Unlock()
+			}
+			wg.Done()
+		}()
+	}
+
+	wg.Wait()
+
+	if v != gr*iters {
+		t.Fatalf("Bad count: got %v, want %v", v, gr*iters)
+	}
+}
+
+func TestAbortWait(t *testing.T) {
+	var s sleeper
+	var m AbortableMutex
+	m.Init()
+
+	// Lock the mutex.
+	m.Lock(&s)
+
+	// Lock again, but this time cancel after 500ms.
+	s.ch = make(chan struct{}, 1)
+	go func() {
+		time.Sleep(500 * time.Millisecond)
+		s.ch <- struct{}{}
+	}()
+	if v := m.Lock(&s); v {
+		t.Fatalf("Lock succeeded when it should have failed")
+	}
+
+	// Lock again, but cancel right away.
+	s.ch <- struct{}{}
+	if v := m.Lock(&s); v {
+		t.Fatalf("Lock succeeded when it should have failed")
+	}
+}