/usr/share/gocode/src/gopkg.in/retry.v1/retry_test.go is in golang-gopkg-retry.v1-dev 0.0~git20161025.0.c09f6b8-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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// Licensed under the LGPLv3, see LICENCE file for details.
package retry_test // import "gopkg.in/retry.v1"
import (
"sort"
"sync"
"time"
gc "gopkg.in/check.v1"
"gopkg.in/retry.v1"
)
type retrySuite struct{}
var _ = gc.Suite(&retrySuite{})
func (*retrySuite) TestAttemptTiming(c *gc.C) {
testAttempt := retry.Regular{
Total: 0.25e9,
Delay: 0.1e9,
}
want := []time.Duration{0, 0.1e9, 0.2e9, 0.2e9}
got := make([]time.Duration, 0, len(want)) // avoid allocation when testing timing
t0 := time.Now()
a := testAttempt.Start(nil)
for a.Next() {
got = append(got, time.Now().Sub(t0))
}
got = append(got, time.Now().Sub(t0))
c.Assert(a.Stopped(), gc.Equals, false)
c.Assert(got, gc.HasLen, len(want))
const margin = 0.01e9
for i, got := range want {
lo := want[i] - margin
hi := want[i] + margin
if got < lo || got > hi {
c.Errorf("attempt %d want %g got %g", i, want[i].Seconds(), got.Seconds())
}
}
}
func (*retrySuite) TestAttemptNextMore(c *gc.C) {
a := retry.Regular{}.Start(nil)
c.Assert(a.Next(), gc.Equals, true)
c.Assert(a.Next(), gc.Equals, false)
a = retry.Regular{}.Start(nil)
c.Assert(a.Next(), gc.Equals, true)
c.Assert(a.More(), gc.Equals, false)
c.Assert(a.Next(), gc.Equals, false)
a = retry.Regular{Total: 2e8}.Start(nil)
c.Assert(a.Next(), gc.Equals, true)
c.Assert(a.More(), gc.Equals, true)
time.Sleep(2e8)
c.Assert(a.More(), gc.Equals, true)
c.Assert(a.Next(), gc.Equals, true)
c.Assert(a.Next(), gc.Equals, false)
a = retry.Regular{Total: 1e8, Min: 2}.Start(nil)
time.Sleep(1e8)
c.Assert(a.Next(), gc.Equals, true)
c.Assert(a.More(), gc.Equals, true)
c.Assert(a.Next(), gc.Equals, true)
c.Assert(a.More(), gc.Equals, false)
c.Assert(a.Next(), gc.Equals, false)
}
func (*retrySuite) TestAttemptWithStop(c *gc.C) {
stop := make(chan struct{})
close(stop)
done := make(chan struct{})
go func() {
strategy := retry.Regular{
Delay: 5 * time.Second,
Total: 30 * time.Second,
}
a := retry.StartWithCancel(strategy, nil, stop)
for a.Next() {
c.Errorf("unexpected attempt")
}
c.Check(a.Stopped(), gc.Equals, true)
close(done)
}()
assertReceive(c, done, "attempt loop abort")
}
func (*retrySuite) TestAttemptWithLaterStop(c *gc.C) {
clock := NewClock(time.Now())
stop := make(chan struct{})
done := make(chan struct{})
progress := make(chan struct{}, 10)
go func() {
strategy := retry.Regular{
Delay: 5 * time.Second,
Total: 30 * time.Second,
}
a := retry.StartWithCancel(strategy, clock, stop)
for a.Next() {
progress <- struct{}{}
}
c.Check(a.Stopped(), gc.Equals, true)
close(done)
}()
assertReceive(c, progress, "progress")
clock.Advance(5 * time.Second)
assertReceive(c, progress, "progress")
clock.Advance(2 * time.Second)
close(stop)
assertReceive(c, done, "attempt loop abort")
select {
case <-progress:
c.Fatalf("unxpected loop iteration after stop")
default:
}
}
func (*retrySuite) TestAttemptWithMockClock(c *gc.C) {
clock := NewClock(time.Now())
strategy := retry.Regular{
Delay: 5 * time.Second,
Total: 30 * time.Second,
}
progress := make(chan struct{})
done := make(chan struct{})
go func() {
for a := strategy.Start(clock); a.Next(); {
progress <- struct{}{}
}
close(done)
}()
assertReceive(c, progress, "progress first time")
clock.Advance(5 * time.Second)
assertReceive(c, progress, "progress second time")
clock.Advance(5 * time.Second)
assertReceive(c, progress, "progress third time")
clock.Advance(30 * time.Second)
assertReceive(c, progress, "progress fourth time")
assertReceive(c, done, "loop finish")
}
type strategyTest struct {
about string
strategy retry.Strategy
calls []nextCall
terminates bool
}
type nextCall struct {
// t holds the time since the timer was started that
// the Next call will be made.
t time.Duration
// delay holds the length of time that a call made at
// time t is expected to sleep for.
sleep time.Duration
}
var strategyTests = []strategyTest{{
about: "regular retry (same params as TestAttemptTiming)",
strategy: retry.Regular{
Total: 0.25e9,
Delay: 0.1e9,
},
calls: []nextCall{
{0, 0},
{0, 0.1e9},
{0.1e9, 0.1e9},
{0.2e9, 0},
},
terminates: true,
}, {
about: "regular retry with calls at different times",
strategy: retry.Regular{
Total: 2.5e9,
Delay: 1e9,
},
calls: []nextCall{
{0.5e9, 0},
{0.5e9, 0.5e9},
{1.1e9, 0.9e9},
{2.2e9, 0},
},
terminates: true,
}, {
about: "regular retry with call after next deadline",
strategy: retry.Regular{
Total: 3.5e9,
Delay: 1e9,
},
calls: []nextCall{
{0.5e9, 0},
// We call Next at well beyond the deadline,
// so we get a zero delay, but subsequent events
// resume pace.
{2e9, 0},
{2.1e9, 0.9e9},
{3e9, 0},
},
terminates: true,
}, {
about: "exponential retry",
strategy: retry.Exponential{
Initial: 1e9,
Factor: 2,
},
calls: []nextCall{
{0, 0},
{0.1e9, 0.9e9},
{1e9, 2e9},
{3e9, 4e9},
{7e9, 8e9},
},
}, {
about: "time-limited exponential retry",
strategy: retry.LimitTime(5e9, retry.Exponential{
Initial: 1e9,
Factor: 2,
}),
calls: []nextCall{
{0, 0},
{0.1e9, 0.9e9},
{1e9, 2e9},
{3e9, 0},
},
terminates: true,
}, {
about: "count-limited exponential retry",
strategy: retry.LimitCount(2, retry.Exponential{
Initial: 1e9,
Factor: 2,
}),
calls: []nextCall{
{0, 0},
{0.1e9, 0.9e9},
{1e9, 0},
},
terminates: true,
}}
func (*retrySuite) TestStrategies(c *gc.C) {
for i, test := range strategyTests {
c.Logf("test %d: %s", i, test.about)
testStrategy(c, test)
}
}
func testStrategy(c *gc.C, test strategyTest) {
t0 := time.Now()
clk := &mockClock{
now: t0,
}
a := retry.Start(test.strategy, clk)
for i, call := range test.calls {
c.Logf("call %d - %v", i, call.t)
clk.now = t0.Add(call.t)
ok := a.Next()
expectTerminate := test.terminates && i == len(test.calls)-1
c.Assert(ok, gc.Equals, !expectTerminate)
if got, want := clk.now.Sub(t0), call.t+call.sleep; !closeTo(got, want) {
c.Fatalf("incorrect time after Next; got %v want %v", got, want)
}
if ok {
c.Assert(a.Count(), gc.Equals, i+1)
}
}
}
func (*retrySuite) TestGapBetweenMoreAndNext(c *gc.C) {
t0 := time.Now().UTC()
clk := &mockClock{
now: t0,
}
a := (&retry.Regular{
Min: 3,
Delay: time.Second,
}).Start(clk)
c.Assert(a.Next(), gc.Equals, true)
c.Assert(clk.now, gc.Equals, t0)
clk.now = clk.now.Add(500 * time.Millisecond)
// Sanity check that the first iteration sleeps for half a second.
c.Assert(a.More(), gc.Equals, true)
c.Assert(a.Next(), gc.Equals, true)
c.Assert(clk.now.Sub(t0), gc.Equals, t0.Add(time.Second).Sub(t0))
clk.now = clk.now.Add(500 * time.Millisecond)
c.Assert(a.More(), gc.Equals, true)
// Add a delay between calling More and Next.
// Next should wait until the correct time anyway.
clk.now = clk.now.Add(250 * time.Millisecond)
c.Assert(a.More(), gc.Equals, true)
c.Assert(a.Next(), gc.Equals, true)
c.Assert(clk.now.Sub(t0), gc.Equals, t0.Add(2*time.Second).Sub(t0))
}
// closeTo reports whether d0 and d1 are close enough
// to one another to cater for inaccuracies of floating point arithmetic.
func closeTo(d0, d1 time.Duration) bool {
const margin = 20 * time.Nanosecond
diff := d1 - d0
if diff < 0 {
diff = -diff
}
return diff < margin
}
type mockClock struct {
now time.Time
sleep func(d time.Duration)
}
func (c *mockClock) After(d time.Duration) <-chan time.Time {
c.now = c.now.Add(d)
ch := make(chan time.Time)
close(ch)
return ch
}
func (c *mockClock) Now() time.Time {
return c.now
}
func assertReceive(c *gc.C, ch <-chan struct{}, what string) {
select {
case <-ch:
case <-time.After(time.Second):
c.Fatalf("timed out waiting for %s", what)
}
}
// Below is code from github.com/juju/testing/clock.go (fortunately with
// the same copyright and license as this file), copied in rather than
// packaging juju/testing and its many (oftentimes circular) dependencies.
// timer implements a mock clock.Timer for testing purposes.
type timer struct {
deadline time.Time
clock *Clock
c chan time.Time
// trigger is called when the timer expires. It is
// called with the clock mutex held and will not block.
trigger func()
}
// Chan is part of the clock.Timer interface.
func (t *timer) Chan() <-chan time.Time {
return t.c
}
// Clock implements a mock clock.Clock for testing purposes.
type Clock struct {
mu sync.Mutex
now time.Time
waiting []*timer // timers waiting to fire, sorted by deadline.
notifyAlarms chan struct{}
}
// NewClock returns a new clock set to the supplied time. If your SUT needs to
// call After, AfterFunc, NewTimer or Timer.Reset more than 10000 times: (1)
// you have probably written a bad test; and (2) you'll need to read from the
// Alarms chan to keep the buffer clear.
func NewClock(now time.Time) *Clock {
return &Clock{
now: now,
notifyAlarms: make(chan struct{}, 10000),
}
}
// Now is part of the clock.Clock interface.
func (clock *Clock) Now() time.Time {
clock.mu.Lock()
defer clock.mu.Unlock()
return clock.now
}
// After is part of the clock.Clock interface.
func (clock *Clock) After(d time.Duration) <-chan time.Time {
return clock.NewTimer(d).Chan()
}
func (clock *Clock) NewTimer(d time.Duration) *timer {
c := make(chan time.Time, 1)
return clock.addAlarm(d, c, func() {
c <- clock.now
})
}
func (clock *Clock) addAlarm(d time.Duration, c chan time.Time, trigger func()) *timer {
defer clock.notifyAlarm()
clock.mu.Lock()
defer clock.mu.Unlock()
t := &timer{
c: c,
deadline: clock.now.Add(d),
clock: clock,
trigger: trigger,
}
clock.addTimer(t)
clock.triggerAll()
return t
}
// Advance advances the result of Now by the supplied duration, and sends
// the "current" time on all alarms which are no longer "in the future".
func (clock *Clock) Advance(d time.Duration) {
clock.mu.Lock()
defer clock.mu.Unlock()
clock.now = clock.now.Add(d)
clock.triggerAll()
}
// triggerAll triggers any alarms that are currently due and removes them
// from clock.waiting.
func (clock *Clock) triggerAll() {
triggered := 0
for _, t := range clock.waiting {
if clock.now.Before(t.deadline) {
break
}
t.trigger()
triggered++
}
clock.waiting = clock.waiting[triggered:]
}
// reset is the underlying implementation of clock.Timer.Reset, which may be
// called by any Timer backed by this Clock.
func (clock *Clock) reset(t *timer, d time.Duration) bool {
defer clock.notifyAlarm()
clock.mu.Lock()
defer clock.mu.Unlock()
found := false
for _, wt := range clock.waiting {
if wt == t {
found = true
}
}
if !found {
clock.waiting = append(clock.waiting, t)
}
t.deadline = clock.now.Add(d)
sort.Sort(byDeadline(clock.waiting))
return found
}
// stop is the underlying implementation of clock.Timer.Reset, which may be
// called by any Timer backed by this Clock.
func (clock *Clock) stop(t *timer) bool {
clock.mu.Lock()
defer clock.mu.Unlock()
for i, wt := range clock.waiting {
if wt == t {
clock.waiting = removeFromSlice(clock.waiting, i)
return true
}
}
return false
}
// addTimer adds an alarm at time t.
func (clock *Clock) addTimer(t *timer) {
clock.waiting = append(clock.waiting, t)
sort.Sort(byDeadline(clock.waiting))
}
// notifyAlarm sends a value on the channel exposed by Alarms().
func (clock *Clock) notifyAlarm() {
select {
case clock.notifyAlarms <- struct{}{}:
default:
panic("alarm notification buffer full")
}
}
// byDeadline is used to sort alarms by time.
type byDeadline []*timer
func (a byDeadline) Len() int { return len(a) }
func (a byDeadline) Less(i, j int) bool { return a[i].deadline.Before(a[j].deadline) }
func (a byDeadline) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
// removeFromSlice removes item at the specified index from the slice.
func removeFromSlice(sl []*timer, index int) []*timer {
return append(sl[:index], sl[index+1:]...)
}
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