rename sharedcalls to singleflight (#1017)

core/syncx/singleflight_test.go

@@ -0,0 +1,141 @@
+package syncx
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func TestExclusiveCallDo(t *testing.T) {
+	g := NewSingleFlight()
+	v, err := g.Do("key", func() (interface{}, error) {
+		return "bar", nil
+	})
+	if got, want := fmt.Sprintf("%v (%T)", v, v), "bar (string)"; got != want {
+		t.Errorf("Do = %v; want %v", got, want)
+	}
+	if err != nil {
+		t.Errorf("Do error = %v", err)
+	}
+}
+
+func TestExclusiveCallDoErr(t *testing.T) {
+	g := NewSingleFlight()
+	someErr := errors.New("some error")
+	v, err := g.Do("key", func() (interface{}, error) {
+		return nil, someErr
+	})
+	if err != someErr {
+		t.Errorf("Do error = %v; want someErr", err)
+	}
+	if v != nil {
+		t.Errorf("unexpected non-nil value %#v", v)
+	}
+}
+
+func TestExclusiveCallDoDupSuppress(t *testing.T) {
+	g := NewSingleFlight()
+	c := make(chan string)
+	var calls int32
+	fn := func() (interface{}, error) {
+		atomic.AddInt32(&calls, 1)
+		return <-c, nil
+	}
+
+	const n = 10
+	var wg sync.WaitGroup
+	for i := 0; i < n; i++ {
+		wg.Add(1)
+		go func() {
+			v, err := g.Do("key", fn)
+			if err != nil {
+				t.Errorf("Do error: %v", err)
+			}
+			if v.(string) != "bar" {
+				t.Errorf("got %q; want %q", v, "bar")
+			}
+			wg.Done()
+		}()
+	}
+	time.Sleep(100 * time.Millisecond) // let goroutines above block
+	c <- "bar"
+	wg.Wait()
+	if got := atomic.LoadInt32(&calls); got != 1 {
+		t.Errorf("number of calls = %d; want 1", got)
+	}
+}
+
+func TestExclusiveCallDoDiffDupSuppress(t *testing.T) {
+	g := NewSingleFlight()
+	broadcast := make(chan struct{})
+	var calls int32
+	tests := []string{"e", "a", "e", "a", "b", "c", "b", "a", "c", "d", "b", "c", "d"}
+
+	var wg sync.WaitGroup
+	for _, key := range tests {
+		wg.Add(1)
+		go func(k string) {
+			<-broadcast // get all goroutines ready
+			_, err := g.Do(k, func() (interface{}, error) {
+				atomic.AddInt32(&calls, 1)
+				time.Sleep(10 * time.Millisecond)
+				return nil, nil
+			})
+			if err != nil {
+				t.Errorf("Do error: %v", err)
+			}
+			wg.Done()
+		}(key)
+	}
+
+	time.Sleep(100 * time.Millisecond) // let goroutines above block
+	close(broadcast)
+	wg.Wait()
+
+	if got := atomic.LoadInt32(&calls); got != 5 {
+		// five letters
+		t.Errorf("number of calls = %d; want 5", got)
+	}
+}
+
+func TestExclusiveCallDoExDupSuppress(t *testing.T) {
+	g := NewSingleFlight()
+	c := make(chan string)
+	var calls int32
+	fn := func() (interface{}, error) {
+		atomic.AddInt32(&calls, 1)
+		return <-c, nil
+	}
+
+	const n = 10
+	var wg sync.WaitGroup
+	var freshes int32
+	for i := 0; i < n; i++ {
+		wg.Add(1)
+		go func() {
+			v, fresh, err := g.DoEx("key", fn)
+			if err != nil {
+				t.Errorf("Do error: %v", err)
+			}
+			if fresh {
+				atomic.AddInt32(&freshes, 1)
+			}
+			if v.(string) != "bar" {
+				t.Errorf("got %q; want %q", v, "bar")
+			}
+			wg.Done()
+		}()
+	}
+	time.Sleep(100 * time.Millisecond) // let goroutines above block
+	c <- "bar"
+	wg.Wait()
+	if got := atomic.LoadInt32(&calls); got != 1 {
+		t.Errorf("number of calls = %d; want 1", got)
+	}
+	if got := atomic.LoadInt32(&freshes); got != 1 {
+		t.Errorf("freshes = %d; want 1", got)
+	}
+}