109 lines
3.1 KiB
Go
109 lines
3.1 KiB
Go
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package backoff
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import (
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"math"
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"testing"
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"time"
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)
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func TestBackOff(t *testing.T) {
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var (
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testInitialInterval = 500 * time.Millisecond
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testRandomizationFactor = 0.1
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testMultiplier = 2.0
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testMaxInterval = 5 * time.Second
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testMaxElapsedTime = 15 * time.Minute
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)
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exp := NewExponentialBackOff()
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exp.InitialInterval = testInitialInterval
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exp.RandomizationFactor = testRandomizationFactor
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exp.Multiplier = testMultiplier
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exp.MaxInterval = testMaxInterval
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exp.MaxElapsedTime = testMaxElapsedTime
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exp.Reset()
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var expectedResults = []time.Duration{500, 1000, 2000, 4000, 5000, 5000, 5000, 5000, 5000, 5000}
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for i, d := range expectedResults {
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expectedResults[i] = d * time.Millisecond
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}
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for _, expected := range expectedResults {
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assertEquals(t, expected, exp.currentInterval)
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// Assert that the next backoff falls in the expected range.
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var minInterval = expected - time.Duration(testRandomizationFactor*float64(expected))
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var maxInterval = expected + time.Duration(testRandomizationFactor*float64(expected))
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var actualInterval = exp.NextBackOff()
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if !(minInterval <= actualInterval && actualInterval <= maxInterval) {
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t.Error("error")
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}
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}
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}
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func TestGetRandomizedInterval(t *testing.T) {
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// 33% chance of being 1.
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assertEquals(t, 1, getRandomValueFromInterval(0.5, 0, 2))
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assertEquals(t, 1, getRandomValueFromInterval(0.5, 0.33, 2))
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// 33% chance of being 2.
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assertEquals(t, 2, getRandomValueFromInterval(0.5, 0.34, 2))
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assertEquals(t, 2, getRandomValueFromInterval(0.5, 0.66, 2))
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// 33% chance of being 3.
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assertEquals(t, 3, getRandomValueFromInterval(0.5, 0.67, 2))
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assertEquals(t, 3, getRandomValueFromInterval(0.5, 0.99, 2))
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}
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type TestClock struct {
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i time.Duration
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start time.Time
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}
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func (c *TestClock) Now() time.Time {
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t := c.start.Add(c.i)
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c.i += time.Second
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return t
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}
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func TestGetElapsedTime(t *testing.T) {
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var exp = NewExponentialBackOff()
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exp.Clock = &TestClock{}
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exp.Reset()
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var elapsedTime = exp.GetElapsedTime()
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if elapsedTime != time.Second {
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t.Errorf("elapsedTime=%d", elapsedTime)
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}
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}
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func TestMaxElapsedTime(t *testing.T) {
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var exp = NewExponentialBackOff()
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exp.Clock = &TestClock{start: time.Time{}.Add(10000 * time.Second)}
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// Change the currentElapsedTime to be 0 ensuring that the elapsed time will be greater
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// than the max elapsed time.
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exp.startTime = time.Time{}
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assertEquals(t, Stop, exp.NextBackOff())
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}
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func TestBackOffOverflow(t *testing.T) {
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var (
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testInitialInterval time.Duration = math.MaxInt64 / 2
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testMaxInterval time.Duration = math.MaxInt64
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testMultiplier = 2.1
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)
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exp := NewExponentialBackOff()
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exp.InitialInterval = testInitialInterval
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exp.Multiplier = testMultiplier
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exp.MaxInterval = testMaxInterval
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exp.Reset()
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exp.NextBackOff()
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// Assert that when an overflow is possible the current varerval time.Duration is set to the max varerval time.Duration .
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assertEquals(t, testMaxInterval, exp.currentInterval)
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}
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func assertEquals(t *testing.T, expected, value time.Duration) {
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if expected != value {
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t.Errorf("got: %d, expected: %d", value, expected)
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}
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}
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