package retry import ( "context" "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 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) } }