backoff_test.go

Documentation: github.com/google/certificate-transparency-go/jsonclient

     1  // Copyright 2017 Google LLC. All Rights Reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package jsonclient
    16  
    17  import (
    18  	"math"
    19  	"testing"
    20  	"time"
    21  )
    22  
    23  const testLeeway = 25 * time.Millisecond
    24  
    25  func fuzzyTimeEquals(a, b time.Time, leeway time.Duration) bool {
    26  	diff := math.Abs(float64(a.Sub(b).Nanoseconds()))
    27  	return diff < float64(leeway.Nanoseconds())
    28  }
    29  
    30  func fuzzyDurationEquals(a, b time.Duration, leeway time.Duration) bool {
    31  	diff := math.Abs(float64(a.Nanoseconds() - b.Nanoseconds()))
    32  	return diff < float64(leeway.Nanoseconds())
    33  }
    34  
    35  func TestBackoff(t *testing.T) {
    36  	b := backoff{}
    37  
    38  	// Test that the interval increases as expected
    39  	for i := uint(0); i < maxMultiplier; i++ {
    40  		n := time.Now()
    41  		interval := b.set(nil)
    42  		if interval != time.Second*(1<<i) {
    43  			t.Fatalf("backoff.set(nil)=%v; want %v", interval, time.Second*(1<<i))
    44  		}
    45  		expected := n.Add(interval)
    46  		until := b.until()
    47  		if !fuzzyTimeEquals(expected, until, time.Millisecond) {
    48  			t.Fatalf("backoff.until()=%v; want %v (+ 0-250ms)", expected, until)
    49  		}
    50  
    51  		// reset notBefore
    52  		b.notBefore = time.Time{}
    53  	}
    54  
    55  	// Test that multiplier doesn't go above maxMultiplier
    56  	b.multiplier = maxMultiplier
    57  	b.notBefore = time.Time{}
    58  	interval := b.set(nil)
    59  	if b.multiplier > maxMultiplier {
    60  		t.Fatalf("backoff.multiplier=%v; want %v", b.multiplier, maxMultiplier)
    61  	}
    62  	if interval > time.Second*(1<<(maxMultiplier-1)) {
    63  		t.Fatalf("backoff.set(nil)=%v; want %v", interval, 1<<(maxMultiplier-1)*time.Second)
    64  	}
    65  
    66  	// Test decreaseMultiplier properly decreases the multiplier
    67  	b.multiplier = 1
    68  	b.notBefore = time.Time{}
    69  	b.decreaseMultiplier()
    70  	if b.multiplier != 0 {
    71  		t.Fatalf("backoff.multiplier=%v; want %v", b.multiplier, 0)
    72  	}
    73  
    74  	// Test decreaseMultiplier doesn't reduce multiplier below 0
    75  	b.decreaseMultiplier()
    76  	if b.multiplier != 0 {
    77  		t.Fatalf("backoff.multiplier=%v; want %v", b.multiplier, 0)
    78  	}
    79  }
    80  
    81  func TestBackoffOverride(t *testing.T) {
    82  	b := backoff{}
    83  	for _, tc := range []struct {
    84  		notBefore        time.Time
    85  		override         time.Duration
    86  		expectedInterval time.Duration
    87  	}{
    88  		{
    89  			notBefore:        time.Now().Add(time.Hour),
    90  			override:         time.Second * 1800,
    91  			expectedInterval: time.Hour,
    92  		},
    93  		{
    94  			notBefore:        time.Now().Add(time.Hour),
    95  			override:         time.Second * 7200,
    96  			expectedInterval: 2 * time.Hour,
    97  		},
    98  		{
    99  			notBefore:        time.Time{},
   100  			override:         time.Second * 7200,
   101  			expectedInterval: 2 * time.Hour,
   102  		},
   103  	} {
   104  		b.multiplier = 0
   105  		b.notBefore = tc.notBefore
   106  		interval := b.set(&tc.override)
   107  		if !fuzzyDurationEquals(tc.expectedInterval, interval, testLeeway) {
   108  			t.Fatalf("backoff.set(%v)=%v; want %v", tc.override, interval, tc.expectedInterval)
   109  		}
   110  	}
   111  }
   112
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