45 lines
840 B
Go
45 lines
840 B
Go
package counter
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import (
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"sync"
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"testing"
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)
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// assertCounter
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// XXX: a copy of Counter is created, but we shouldn't copy a mutex. Use pointer instead.
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func assertCounter(t testing.TB, got *Counter, want int) {
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t.Helper()
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if got.Value() != want {
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t.Errorf("got %d, want %d", got.Value(), want)
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}
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}
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func TestCounter(t *testing.T) {
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t.Run("incrementing the counter 3 times leaves it at 3", func(t *testing.T) {
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counter := NewCounter()
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counter.Inc()
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counter.Inc()
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counter.Inc()
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assertCounter(t, counter, 3)
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})
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t.Run("it runs safely concurrently", func(t *testing.T) {
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wantedCount := 1000
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counter := NewCounter()
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var wg sync.WaitGroup
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wg.Add(wantedCount)
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for i := 0; i < wantedCount; i++ {
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go func() {
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counter.Inc()
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wg.Done()
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}()
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}
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wg.Wait()
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assertCounter(t, counter, wantedCount)
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})
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}
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