open-consul/lib/retry/retry_test.go

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package retry
import (
"context"
"fmt"
"math"
"testing"
"time"
"github.com/stretchr/testify/require"
)
func TestJitter(t *testing.T) {
repeat(t, "0 percent", func(t *testing.T) {
jitter := NewJitter(0)
for i := 0; i < 10; i++ {
baseTime := time.Duration(i) * time.Second
require.Equal(t, baseTime, jitter(baseTime))
}
})
repeat(t, "10 percent", func(t *testing.T) {
jitter := NewJitter(10)
baseTime := 5000 * time.Millisecond
maxTime := 5500 * time.Millisecond
newTime := jitter(baseTime)
require.True(t, newTime > baseTime)
require.True(t, newTime <= maxTime)
})
repeat(t, "100 percent", func(t *testing.T) {
jitter := NewJitter(100)
baseTime := 1234 * time.Millisecond
maxTime := 2468 * time.Millisecond
newTime := jitter(baseTime)
require.True(t, newTime > baseTime)
require.True(t, newTime <= maxTime)
})
repeat(t, "overflow", func(t *testing.T) {
jitter := NewJitter(100)
baseTime := time.Duration(math.MaxInt64) - 2*time.Hour
newTime := jitter(baseTime)
require.Equal(t, baseTime, newTime)
})
}
func repeat(t *testing.T, name string, fn func(t *testing.T)) {
t.Run(name, func(t *testing.T) {
for i := 0; i < 1000; i++ {
fn(t)
}
})
}
func TestWaiter_Delay(t *testing.T) {
t.Run("zero value", func(t *testing.T) {
w := &Waiter{}
for i, expected := range []time.Duration{0, 1, 2, 4, 8, 16, 32, 64, 128} {
w.failures = uint(i)
require.Equal(t, expected*time.Second, w.delay(), "failure count: %d", i)
}
})
t.Run("with minimum wait", func(t *testing.T) {
w := &Waiter{MinWait: 5 * time.Second}
for i, expected := range []time.Duration{5, 5, 5, 5, 8, 16, 32, 64, 128} {
w.failures = uint(i)
require.Equal(t, expected*time.Second, w.delay(), "failure count: %d", i)
}
})
t.Run("with maximum wait", func(t *testing.T) {
w := &Waiter{MaxWait: 20 * time.Second}
for i, expected := range []time.Duration{0, 1, 2, 4, 8, 16, 20, 20, 20} {
w.failures = uint(i)
require.Equal(t, expected*time.Second, w.delay(), "failure count: %d", i)
}
})
t.Run("with minimum failures", func(t *testing.T) {
w := &Waiter{MinFailures: 4}
for i, expected := range []time.Duration{0, 0, 0, 0, 0, 1, 2, 4, 8, 16} {
w.failures = uint(i)
require.Equal(t, expected*time.Second, w.delay(), "failure count: %d", i)
}
})
t.Run("with factor", func(t *testing.T) {
w := &Waiter{Factor: time.Millisecond}
for i, expected := range []time.Duration{0, 1, 2, 4, 8, 16, 32, 64, 128} {
w.failures = uint(i)
require.Equal(t, expected*time.Millisecond, w.delay(), "failure count: %d", i)
}
})
t.Run("with all settings", func(t *testing.T) {
w := &Waiter{
MinFailures: 2,
MinWait: 4 * time.Millisecond,
MaxWait: 20 * time.Millisecond,
Factor: time.Millisecond,
}
for i, expected := range []time.Duration{4, 4, 4, 4, 4, 4, 8, 16, 20, 20, 20} {
w.failures = uint(i)
require.Equal(t, expected*time.Millisecond, w.delay(), "failure count: %d", i)
}
})
t.Run("jitter can exceed MaxWait", func(t *testing.T) {
w := &Waiter{
MaxWait: 20 * time.Second,
Jitter: NewJitter(300),
failures: 30,
}
delay := w.delay()
require.True(t, delay > 20*time.Second, "expected delay %v to be greater than MaxWait %v", delay, w.MaxWait)
})
}
func TestWaiter_Wait(t *testing.T) {
if testing.Short() {
t.Skip("too slow for testing.Short")
}
ctx := context.Background()
t.Run("first failure", func(t *testing.T) {
w := &Waiter{MinWait: time.Millisecond, Factor: 1}
elapsed, err := runWait(ctx, w)
require.NoError(t, err)
assertApproximateDuration(t, elapsed, time.Millisecond)
require.Equal(t, w.failures, uint(1))
})
t.Run("max failures", func(t *testing.T) {
w := &Waiter{
MaxWait: 100 * time.Millisecond,
failures: 200,
}
elapsed, err := runWait(ctx, w)
require.NoError(t, err)
assertApproximateDuration(t, elapsed, 100*time.Millisecond)
require.Equal(t, w.failures, uint(201))
})
t.Run("context deadline", func(t *testing.T) {
w := &Waiter{failures: 200, MinWait: time.Second}
ctx, cancel := context.WithTimeout(ctx, 5*time.Millisecond)
t.Cleanup(cancel)
elapsed, err := runWait(ctx, w)
require.Equal(t, err, context.DeadlineExceeded)
assertApproximateDuration(t, elapsed, 5*time.Millisecond)
require.Equal(t, w.failures, uint(201))
})
}
func TestWaiter_RetryLoop(t *testing.T) {
if testing.Short() {
t.Skip("too slow for testing.Short")
}
// Change the default factor so that we retry faster.
w := &Waiter{Factor: 1 * time.Millisecond}
t.Run("exits if operation is successful after a few reties", func(t *testing.T) {
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
t.Cleanup(cancel)
numRetries := 0
err := w.RetryLoop(ctx, func() error {
if numRetries < 2 {
numRetries++
return fmt.Errorf("operation not successful")
}
return nil
})
require.NoError(t, err)
})
t.Run("errors if operation is never successful", func(t *testing.T) {
ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
t.Cleanup(cancel)
err := w.RetryLoop(ctx, func() error {
return fmt.Errorf("operation not successful")
})
require.NotNil(t, err)
require.EqualError(t, err, "could not retry operation: operation not successful")
})
}
func runWait(ctx context.Context, w *Waiter) (time.Duration, error) {
before := time.Now()
err := w.Wait(ctx)
return time.Since(before), err
}
func assertApproximateDuration(t *testing.T, actual time.Duration, expected time.Duration) {
t.Helper()
delta := 20 * time.Millisecond
min, max := expected-delta, expected+delta
if min < 0 {
min = 0
}
if actual < min || actual > max {
t.Fatalf("expected %v to be between %v and %v", actual, min, max)
}
}