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package stream
import (
"fmt"
"sync/atomic"
"testing"
"time"
"github.com/stretchr/testify/require"
)
func ExampleStream() {
times := []int{20, 52, 16, 45, 4, 80}
stream := New()
for _, millis := range times {
dur := time.Duration(millis) * time.Millisecond
stream.Go(func() Callback {
time.Sleep(dur)
// This will print in the order the tasks were submitted
return func() { fmt.Println(dur) }
})
}
stream.Wait()
// Output:
// 20ms
// 52ms
// 16ms
// 45ms
// 4ms
// 80ms
}
func TestStream(t *testing.T) {
t.Parallel()
t.Run("simple", func(t *testing.T) {
t.Parallel()
s := New()
var res []int
for i := 0; i < 5; i++ {
i := i
s.Go(func() Callback {
i *= 2
return func() {
res = append(res, i)
}
})
}
s.Wait()
require.Equal(t, []int{0, 2, 4, 6, 8}, res)
})
t.Run("max goroutines", func(t *testing.T) {
t.Parallel()
s := New().WithMaxGoroutines(5)
var currentTaskCount atomic.Int64
var currentCallbackCount atomic.Int64
for i := 0; i < 50; i++ {
s.Go(func() Callback {
curr := currentTaskCount.Add(1)
if curr > 5 {
t.Fatal("too many concurrent tasks being executed")
}
defer currentTaskCount.Add(-1)
time.Sleep(time.Millisecond)
return func() {
curr := currentCallbackCount.Add(1)
if curr > 1 {
t.Fatal("too many concurrent callbacks being executed")
}
time.Sleep(time.Millisecond)
defer currentCallbackCount.Add(-1)
}
})
}
s.Wait()
})
t.Run("panic in task is propagated", func(t *testing.T) {
t.Parallel()
s := New().WithMaxGoroutines(5)
s.Go(func() Callback {
panic("something really bad happened in the task")
})
require.Panics(t, s.Wait)
})
t.Run("panic in callback is propagated", func(t *testing.T) {
t.Parallel()
s := New().WithMaxGoroutines(5)
s.Go(func() Callback {
return func() {
panic("something really bad happened in the callback")
}
})
require.Panics(t, s.Wait)
})
t.Run("panic in callback does not block producers", func(t *testing.T) {
t.Parallel()
s := New().WithMaxGoroutines(5)
s.Go(func() Callback {
return func() {
panic("something really bad happened in the callback")
}
})
for i := 0; i < 100; i++ {
s.Go(func() Callback {
return func() {}
})
}
require.Panics(t, s.Wait)
})
}
func BenchmarkStream(b *testing.B) {
b.Run("startup and teardown", func(b *testing.B) {
for i := 0; i < b.N; i++ {
s := New()
s.Go(func() Callback { return func() {} })
s.Wait()
}
})
b.Run("per task", func(b *testing.B) {
n := 0
s := New()
for i := 0; i < b.N; i++ {
s.Go(func() Callback {
return func() {
n += 1
}
})
}
s.Wait()
})
}
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