fix test flake due to dependency on time.Timer

contrib/mesos/pkg/minion/tasks/task.go

@@ -281,7 +281,7 @@ func taskRunning(t *Task) taskStateFn {
 
 	select {
 	case <-t.shouldQuit:
-		t.tryComplete(t.awaitDeath(defaultKillGracePeriod, waitCh))
+		t.tryComplete(t.awaitDeath(&realTimer{}, defaultKillGracePeriod, waitCh))
 	case wr := <-waitCh:
 		t.tryComplete(wr)
 	}
@@ -290,7 +290,9 @@ func taskRunning(t *Task) taskStateFn {
 
 // awaitDeath waits for the process to complete, or else for a "quit" signal on the task-
 // at which point we'll attempt to kill manually.
-func (t *Task) awaitDeath(gracePeriod time.Duration, waitCh <-chan *Completion) *Completion {
+func (t *Task) awaitDeath(timer timer, gracePeriod time.Duration, waitCh <-chan *Completion) *Completion {
+	defer timer.discard()
+
 	select {
 	case wr := <-waitCh:
 		// got a signal to quit, but we're already finished
@@ -318,10 +320,11 @@ waitLoop:
 		}
 
 		// Wait for the kill to be processed, and child proc resources cleaned up; try to avoid zombies!
+		timer.set(gracePeriod)
 		select {
 		case wr = <-waitCh:
 			break waitLoop
-		case <-time.After(gracePeriod):
+		case <-timer.await():
 			// want a timeout, but a shorter one than we used initially.
 			// using /= 2 is deterministic and yields the desirable effect.
 			gracePeriod /= 2

contrib/mesos/pkg/minion/tasks/task_test.go

@@ -24,6 +24,7 @@ import (
 	"sync"
 	"syscall"
 	"testing"
+	"time"
 
 	log "github.com/golang/glog"
 	"github.com/stretchr/testify/assert"
@@ -222,15 +223,28 @@ func TestMergeOutput(t *testing.T) {
 	<-te.Done() // wait for the merge to complete
 }
 
+type fakeTimer struct {
+	ch chan time.Time
+}
+
+func (t *fakeTimer) set(d time.Duration)     {}
+func (t *fakeTimer) discard()                {}
+func (t *fakeTimer) await() <-chan time.Time { return t.ch }
+func (t *fakeTimer) expire()                 { t.ch = make(chan time.Time); close(t.ch) }
+func (t *fakeTimer) reset()                  { t.ch = nil }
+
 func TestAfterDeath(t *testing.T) {
 	// test kill escalation since that's not covered by other unit tests
 	t1 := New("foo", "", nil, nil, devNull)
 	kills := 0
 	waitCh := make(chan *Completion, 1)
+	timer := &fakeTimer{}
+	timer.expire()
 	t1.killFunc = func(force bool) (int, error) {
 		// > 0 is intentional, multiple calls to close() should panic
 		if kills > 0 {
 			assert.True(t, force)
+			timer.reset() // don't want to race w/ waitCh
 			waitCh <- &Completion{name: t1.name, code: 123}
 			close(waitCh)
 		} else {
@@ -239,7 +253,7 @@ func TestAfterDeath(t *testing.T) {
 		kills++
 		return 0, nil
 	}
-	wr := t1.awaitDeath(0, waitCh)
+	wr := t1.awaitDeath(timer, 0, waitCh)
 	assert.Equal(t, "foo", wr.name)
 	assert.Equal(t, 123, wr.code)
 	assert.NoError(t, wr.err)
@@ -252,7 +266,9 @@ func TestAfterDeath(t *testing.T) {
 		t.Fatalf("should not attempt to kill a task that has already reported completion")
 		return 0, nil
 	}
-	wr = t1.awaitDeath(0, waitCh)
+
+	timer.reset() // don't race w/ waitCh
+	wr = t1.awaitDeath(timer, 0, waitCh)
 	assert.Equal(t, 456, wr.code)
 	assert.NoError(t, wr.err)
 
@@ -270,7 +286,8 @@ func TestAfterDeath(t *testing.T) {
 		kills++
 		return 0, nil
 	}
-	wr = t1.awaitDeath(0, nil)
+	timer.expire()
+	wr = t1.awaitDeath(timer, 0, nil)
 	assert.Equal(t, "foo", wr.name)
 	assert.Error(t, wr.err)
 
@@ -287,7 +304,8 @@ func TestAfterDeath(t *testing.T) {
 		kills++
 		return 0, killFailed
 	}
-	wr = t1.awaitDeath(0, nil)
+	timer.expire()
+	wr = t1.awaitDeath(timer, 0, nil)
 	assert.Equal(t, "foo", wr.name)
 	assert.Error(t, wr.err)
 }

contrib/mesos/pkg/minion/tasks/timer.go

@@ -0,0 +1,52 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+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 tasks
+
+import (
+	"time"
+)
+
+type timer interface {
+	set(time.Duration)
+	discard()
+	await() <-chan time.Time
+}
+
+type realTimer struct {
+	*time.Timer
+}
+
+func (t *realTimer) set(d time.Duration) {
+	if t.Timer == nil {
+		t.Timer = time.NewTimer(d)
+	} else {
+		t.Reset(d)
+	}
+}
+
+func (t *realTimer) await() <-chan time.Time {
+	if t.Timer == nil {
+		return nil
+	}
+	return t.C
+}
+
+func (t *realTimer) discard() {
+	if t.Timer != nil {
+		t.Stop()
+	}
+}