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|
package test
import (
"errors"
"math/rand"
"testing"
"time"
)
type flaky struct {
t testing.TB
o *FlakyOptions
}
type FlakyOptions struct {
InitialBackoff time.Duration
MaxAttempts int
Jitter float64
}
func NewFlaky(t testing.TB, o *FlakyOptions) *flaky {
if o.InitialBackoff <= 0 {
o.InitialBackoff = 500 * time.Millisecond
}
if o.MaxAttempts <= 0 {
o.MaxAttempts = 3
}
if o.Jitter < 0 {
o.Jitter = 0
}
return &flaky{t: t, o: o}
}
func (f *flaky) Run(fn func(t testing.TB)) {
var last error
for attempt := 1; attempt <= f.o.MaxAttempts; attempt++ {
f.t.Logf("attempt %d of %d", attempt, f.o.MaxAttempts)
r := &recorder{
TB: f.t,
fail: func(s string) { last = errors.New(s) },
fatal: func(s string) { last = errors.New(s) },
}
func() {
defer func() {
if v := recover(); v != nil {
if code, ok := v.(int); ok && code != RecorderFailNow {
panic(v)
}
}
}()
fn(r)
}()
if !r.Failed() {
return
}
if attempt < f.o.MaxAttempts {
backoff := f.o.InitialBackoff * time.Duration(1<<uint(attempt-1))
time.Sleep(applyJitter(backoff, f.o.Jitter))
}
}
f.t.Fatalf("[%s] test failed after %d attempts: %v", f.t.Name(), f.o.MaxAttempts, last)
}
func applyJitter(d time.Duration, jitter float64) time.Duration {
if jitter == 0 {
return d
}
maxJitter := float64(d) * jitter
delta := maxJitter * (rand.Float64()*2 - 1)
return time.Duration(float64(d) + delta)
}
|
