76 lines
1.8 KiB
Go
76 lines
1.8 KiB
Go
package singleton_test
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import (
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"sync"
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"sync/atomic"
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"testing"
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"github.com/google/uuid"
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"github.com/navidrome/navidrome/utils/singleton"
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. "github.com/onsi/ginkgo/v2"
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. "github.com/onsi/gomega"
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)
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func TestSingleton(t *testing.T) {
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RegisterFailHandler(Fail)
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RunSpecs(t, "Singleton Suite")
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}
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var _ = Describe("Get", func() {
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type T struct{ id string }
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var numInstances int
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constructor := func() interface{} {
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numInstances++
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return &T{id: uuid.NewString()}
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}
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It("calls the constructor to create a new instance", func() {
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instance := singleton.Get(T{}, constructor)
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Expect(numInstances).To(Equal(1))
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Expect(instance).To(BeAssignableToTypeOf(&T{}))
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})
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It("does not call the constructor the next time", func() {
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instance := singleton.Get(T{}, constructor)
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newInstance := singleton.Get(T{}, constructor)
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Expect(newInstance.(*T).id).To(Equal(instance.(*T).id))
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Expect(numInstances).To(Equal(1))
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})
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It("does not call the constructor even if a pointer is passed as the object", func() {
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instance := singleton.Get(T{}, constructor)
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newInstance := singleton.Get(&T{}, constructor)
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Expect(newInstance.(*T).id).To(Equal(instance.(*T).id))
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Expect(numInstances).To(Equal(1))
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})
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It("only calls the constructor once when called concurrently", func() {
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const maxCalls = 2000
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var numCalls int32
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start := sync.WaitGroup{}
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start.Add(1)
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prepare := sync.WaitGroup{}
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prepare.Add(maxCalls)
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done := sync.WaitGroup{}
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done.Add(maxCalls)
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for i := 0; i < maxCalls; i++ {
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go func() {
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start.Wait()
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singleton.Get(T{}, constructor)
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atomic.AddInt32(&numCalls, 1)
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done.Done()
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}()
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prepare.Done()
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}
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prepare.Wait()
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start.Done()
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done.Wait()
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Expect(numCalls).To(Equal(int32(maxCalls)))
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Expect(numInstances).To(Equal(1))
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})
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})
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