449 lines
11 KiB
Go
449 lines
11 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build go1.7
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package rate
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import (
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"context"
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"math"
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"runtime"
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"sync"
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"sync/atomic"
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"testing"
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"time"
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)
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func TestLimit(t *testing.T) {
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if Limit(10) == Inf {
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t.Errorf("Limit(10) == Inf should be false")
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}
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}
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func closeEnough(a, b Limit) bool {
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return (math.Abs(float64(a)/float64(b)) - 1.0) < 1e-9
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}
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func TestEvery(t *testing.T) {
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cases := []struct {
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interval time.Duration
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lim Limit
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}{
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{0, Inf},
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{-1, Inf},
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{1 * time.Nanosecond, Limit(1e9)},
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{1 * time.Microsecond, Limit(1e6)},
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{1 * time.Millisecond, Limit(1e3)},
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{10 * time.Millisecond, Limit(100)},
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{100 * time.Millisecond, Limit(10)},
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{1 * time.Second, Limit(1)},
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{2 * time.Second, Limit(0.5)},
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{time.Duration(2.5 * float64(time.Second)), Limit(0.4)},
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{4 * time.Second, Limit(0.25)},
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{10 * time.Second, Limit(0.1)},
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{time.Duration(math.MaxInt64), Limit(1e9 / float64(math.MaxInt64))},
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}
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for _, tc := range cases {
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lim := Every(tc.interval)
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if !closeEnough(lim, tc.lim) {
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t.Errorf("Every(%v) = %v want %v", tc.interval, lim, tc.lim)
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}
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}
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}
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const (
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d = 100 * time.Millisecond
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)
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var (
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t0 = time.Now()
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t1 = t0.Add(time.Duration(1) * d)
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t2 = t0.Add(time.Duration(2) * d)
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t3 = t0.Add(time.Duration(3) * d)
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t4 = t0.Add(time.Duration(4) * d)
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t5 = t0.Add(time.Duration(5) * d)
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t9 = t0.Add(time.Duration(9) * d)
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)
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type allow struct {
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t time.Time
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n int
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ok bool
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}
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func run(t *testing.T, lim *Limiter, allows []allow) {
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for i, allow := range allows {
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ok := lim.AllowN(allow.t, allow.n)
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if ok != allow.ok {
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t.Errorf("step %d: lim.AllowN(%v, %v) = %v want %v",
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i, allow.t, allow.n, ok, allow.ok)
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}
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}
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}
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func TestLimiterBurst1(t *testing.T) {
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run(t, NewLimiter(10, 1), []allow{
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{t0, 1, true},
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{t0, 1, false},
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{t0, 1, false},
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{t1, 1, true},
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{t1, 1, false},
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{t1, 1, false},
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{t2, 2, false}, // burst size is 1, so n=2 always fails
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{t2, 1, true},
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{t2, 1, false},
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})
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}
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func TestLimiterBurst3(t *testing.T) {
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run(t, NewLimiter(10, 3), []allow{
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{t0, 2, true},
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{t0, 2, false},
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{t0, 1, true},
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{t0, 1, false},
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{t1, 4, false},
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{t2, 1, true},
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{t3, 1, true},
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{t4, 1, true},
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{t4, 1, true},
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{t4, 1, false},
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{t4, 1, false},
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{t9, 3, true},
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{t9, 0, true},
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})
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}
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func TestLimiterJumpBackwards(t *testing.T) {
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run(t, NewLimiter(10, 3), []allow{
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{t1, 1, true}, // start at t1
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{t0, 1, true}, // jump back to t0, two tokens remain
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{t0, 1, true},
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{t0, 1, false},
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{t0, 1, false},
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{t1, 1, true}, // got a token
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{t1, 1, false},
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{t1, 1, false},
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{t2, 1, true}, // got another token
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{t2, 1, false},
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{t2, 1, false},
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})
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}
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func TestSimultaneousRequests(t *testing.T) {
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const (
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limit = 1
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burst = 5
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numRequests = 15
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)
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var (
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wg sync.WaitGroup
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numOK = uint32(0)
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)
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// Very slow replenishing bucket.
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lim := NewLimiter(limit, burst)
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// Tries to take a token, atomically updates the counter and decreases the wait
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// group counter.
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f := func() {
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defer wg.Done()
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if ok := lim.Allow(); ok {
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atomic.AddUint32(&numOK, 1)
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}
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}
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wg.Add(numRequests)
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for i := 0; i < numRequests; i++ {
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go f()
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}
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wg.Wait()
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if numOK != burst {
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t.Errorf("numOK = %d, want %d", numOK, burst)
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}
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}
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func TestLongRunningQPS(t *testing.T) {
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if testing.Short() {
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t.Skip("skipping in short mode")
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}
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if runtime.GOOS == "openbsd" {
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t.Skip("low resolution time.Sleep invalidates test (golang.org/issue/14183)")
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return
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}
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// The test runs for a few seconds executing many requests and then checks
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// that overall number of requests is reasonable.
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const (
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limit = 100
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burst = 100
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)
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var numOK = int32(0)
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lim := NewLimiter(limit, burst)
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var wg sync.WaitGroup
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f := func() {
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if ok := lim.Allow(); ok {
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atomic.AddInt32(&numOK, 1)
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}
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wg.Done()
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}
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start := time.Now()
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end := start.Add(5 * time.Second)
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for time.Now().Before(end) {
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wg.Add(1)
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go f()
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// This will still offer ~500 requests per second, but won't consume
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// outrageous amount of CPU.
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time.Sleep(2 * time.Millisecond)
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}
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wg.Wait()
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elapsed := time.Since(start)
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ideal := burst + (limit * float64(elapsed) / float64(time.Second))
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// We should never get more requests than allowed.
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if want := int32(ideal + 1); numOK > want {
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t.Errorf("numOK = %d, want %d (ideal %f)", numOK, want, ideal)
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}
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// We should get very close to the number of requests allowed.
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if want := int32(0.999 * ideal); numOK < want {
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t.Errorf("numOK = %d, want %d (ideal %f)", numOK, want, ideal)
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}
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}
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type request struct {
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t time.Time
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n int
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act time.Time
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ok bool
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}
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// dFromDuration converts a duration to a multiple of the global constant d
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func dFromDuration(dur time.Duration) int {
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// Adding a millisecond to be swallowed by the integer division
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// because we don't care about small inaccuracies
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return int((dur + time.Millisecond) / d)
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}
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// dSince returns multiples of d since t0
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func dSince(t time.Time) int {
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return dFromDuration(t.Sub(t0))
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}
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func runReserve(t *testing.T, lim *Limiter, req request) *Reservation {
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return runReserveMax(t, lim, req, InfDuration)
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}
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func runReserveMax(t *testing.T, lim *Limiter, req request, maxReserve time.Duration) *Reservation {
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r := lim.reserveN(req.t, req.n, maxReserve)
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if r.ok && (dSince(r.timeToAct) != dSince(req.act)) || r.ok != req.ok {
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t.Errorf("lim.reserveN(t%d, %v, %v) = (t%d, %v) want (t%d, %v)",
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dSince(req.t), req.n, maxReserve, dSince(r.timeToAct), r.ok, dSince(req.act), req.ok)
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}
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return &r
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}
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func TestSimpleReserve(t *testing.T) {
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lim := NewLimiter(10, 2)
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runReserve(t, lim, request{t0, 2, t0, true})
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runReserve(t, lim, request{t0, 2, t2, true})
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runReserve(t, lim, request{t3, 2, t4, true})
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}
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func TestMix(t *testing.T) {
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lim := NewLimiter(10, 2)
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runReserve(t, lim, request{t0, 3, t1, false}) // should return false because n > Burst
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runReserve(t, lim, request{t0, 2, t0, true})
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run(t, lim, []allow{{t1, 2, false}}) // not enought tokens - don't allow
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runReserve(t, lim, request{t1, 2, t2, true})
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run(t, lim, []allow{{t1, 1, false}}) // negative tokens - don't allow
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run(t, lim, []allow{{t3, 1, true}})
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}
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func TestCancelInvalid(t *testing.T) {
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lim := NewLimiter(10, 2)
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runReserve(t, lim, request{t0, 2, t0, true})
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r := runReserve(t, lim, request{t0, 3, t3, false})
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r.CancelAt(t0) // should have no effect
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runReserve(t, lim, request{t0, 2, t2, true}) // did not get extra tokens
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}
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func TestCancelLast(t *testing.T) {
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lim := NewLimiter(10, 2)
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runReserve(t, lim, request{t0, 2, t0, true})
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r := runReserve(t, lim, request{t0, 2, t2, true})
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r.CancelAt(t1) // got 2 tokens back
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runReserve(t, lim, request{t1, 2, t2, true})
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}
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func TestCancelTooLate(t *testing.T) {
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lim := NewLimiter(10, 2)
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runReserve(t, lim, request{t0, 2, t0, true})
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r := runReserve(t, lim, request{t0, 2, t2, true})
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r.CancelAt(t3) // too late to cancel - should have no effect
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runReserve(t, lim, request{t3, 2, t4, true})
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}
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func TestCancel0Tokens(t *testing.T) {
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lim := NewLimiter(10, 2)
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runReserve(t, lim, request{t0, 2, t0, true})
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r := runReserve(t, lim, request{t0, 1, t1, true})
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runReserve(t, lim, request{t0, 1, t2, true})
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r.CancelAt(t0) // got 0 tokens back
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runReserve(t, lim, request{t0, 1, t3, true})
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}
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func TestCancel1Token(t *testing.T) {
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lim := NewLimiter(10, 2)
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runReserve(t, lim, request{t0, 2, t0, true})
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r := runReserve(t, lim, request{t0, 2, t2, true})
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runReserve(t, lim, request{t0, 1, t3, true})
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r.CancelAt(t2) // got 1 token back
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runReserve(t, lim, request{t2, 2, t4, true})
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}
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func TestCancelMulti(t *testing.T) {
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lim := NewLimiter(10, 4)
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runReserve(t, lim, request{t0, 4, t0, true})
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rA := runReserve(t, lim, request{t0, 3, t3, true})
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runReserve(t, lim, request{t0, 1, t4, true})
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rC := runReserve(t, lim, request{t0, 1, t5, true})
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rC.CancelAt(t1) // get 1 token back
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rA.CancelAt(t1) // get 2 tokens back, as if C was never reserved
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runReserve(t, lim, request{t1, 3, t5, true})
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}
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func TestReserveJumpBack(t *testing.T) {
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lim := NewLimiter(10, 2)
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runReserve(t, lim, request{t1, 2, t1, true}) // start at t1
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runReserve(t, lim, request{t0, 1, t1, true}) // should violate Limit,Burst
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runReserve(t, lim, request{t2, 2, t3, true})
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}
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func TestReserveJumpBackCancel(t *testing.T) {
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lim := NewLimiter(10, 2)
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runReserve(t, lim, request{t1, 2, t1, true}) // start at t1
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r := runReserve(t, lim, request{t1, 2, t3, true})
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runReserve(t, lim, request{t1, 1, t4, true})
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r.CancelAt(t0) // cancel at t0, get 1 token back
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runReserve(t, lim, request{t1, 2, t4, true}) // should violate Limit,Burst
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}
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func TestReserveSetLimit(t *testing.T) {
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lim := NewLimiter(5, 2)
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runReserve(t, lim, request{t0, 2, t0, true})
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runReserve(t, lim, request{t0, 2, t4, true})
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lim.SetLimitAt(t2, 10)
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runReserve(t, lim, request{t2, 1, t4, true}) // violates Limit and Burst
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}
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func TestReserveSetLimitCancel(t *testing.T) {
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lim := NewLimiter(5, 2)
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runReserve(t, lim, request{t0, 2, t0, true})
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r := runReserve(t, lim, request{t0, 2, t4, true})
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lim.SetLimitAt(t2, 10)
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r.CancelAt(t2) // 2 tokens back
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runReserve(t, lim, request{t2, 2, t3, true})
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}
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func TestReserveMax(t *testing.T) {
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lim := NewLimiter(10, 2)
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maxT := d
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runReserveMax(t, lim, request{t0, 2, t0, true}, maxT)
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runReserveMax(t, lim, request{t0, 1, t1, true}, maxT) // reserve for close future
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runReserveMax(t, lim, request{t0, 1, t2, false}, maxT) // time to act too far in the future
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}
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type wait struct {
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name string
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ctx context.Context
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n int
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delay int // in multiples of d
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nilErr bool
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}
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func runWait(t *testing.T, lim *Limiter, w wait) {
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start := time.Now()
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err := lim.WaitN(w.ctx, w.n)
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delay := time.Now().Sub(start)
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if (w.nilErr && err != nil) || (!w.nilErr && err == nil) || w.delay != dFromDuration(delay) {
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errString := "<nil>"
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if !w.nilErr {
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errString = "<non-nil error>"
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}
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t.Errorf("lim.WaitN(%v, lim, %v) = %v with delay %v ; want %v with delay %v",
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w.name, w.n, err, delay, errString, d*time.Duration(w.delay))
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}
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}
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func TestWaitSimple(t *testing.T) {
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lim := NewLimiter(10, 3)
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ctx, cancel := context.WithCancel(context.Background())
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cancel()
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runWait(t, lim, wait{"already-cancelled", ctx, 1, 0, false})
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runWait(t, lim, wait{"exceed-burst-error", context.Background(), 4, 0, false})
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runWait(t, lim, wait{"act-now", context.Background(), 2, 0, true})
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runWait(t, lim, wait{"act-later", context.Background(), 3, 2, true})
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}
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func TestWaitCancel(t *testing.T) {
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lim := NewLimiter(10, 3)
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ctx, cancel := context.WithCancel(context.Background())
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runWait(t, lim, wait{"act-now", ctx, 2, 0, true}) // after this lim.tokens = 1
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go func() {
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time.Sleep(d)
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cancel()
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}()
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runWait(t, lim, wait{"will-cancel", ctx, 3, 1, false})
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// should get 3 tokens back, and have lim.tokens = 2
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t.Logf("tokens:%v last:%v lastEvent:%v", lim.tokens, lim.last, lim.lastEvent)
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runWait(t, lim, wait{"act-now-after-cancel", context.Background(), 2, 0, true})
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}
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func TestWaitTimeout(t *testing.T) {
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lim := NewLimiter(10, 3)
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ctx, cancel := context.WithTimeout(context.Background(), d)
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defer cancel()
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runWait(t, lim, wait{"act-now", ctx, 2, 0, true})
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runWait(t, lim, wait{"w-timeout-err", ctx, 3, 0, false})
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}
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func TestWaitInf(t *testing.T) {
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lim := NewLimiter(Inf, 0)
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runWait(t, lim, wait{"exceed-burst-no-error", context.Background(), 3, 0, true})
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}
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func BenchmarkAllowN(b *testing.B) {
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lim := NewLimiter(Every(1*time.Second), 1)
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now := time.Now()
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b.ReportAllocs()
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b.ResetTimer()
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b.RunParallel(func(pb *testing.PB) {
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for pb.Next() {
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lim.AllowN(now, 1)
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}
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})
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}
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