add queue package

core/queue/balancedqueuepusher_test.go

@@ -0,0 +1,43 @@
+package queue
+
+import (
+	"fmt"
+	"strconv"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBalancedQueuePusher(t *testing.T) {
+	const numPushers = 100
+	var pushers []Pusher
+	var mockedPushers []*mockedPusher
+	for i := 0; i < numPushers; i++ {
+		p := &mockedPusher{
+			name: "pusher:" + strconv.Itoa(i),
+		}
+		pushers = append(pushers, p)
+		mockedPushers = append(mockedPushers, p)
+	}
+
+	pusher := NewBalancedQueuePusher(pushers)
+	assert.True(t, len(pusher.Name()) > 0)
+
+	for i := 0; i < numPushers*1000; i++ {
+		assert.Nil(t, pusher.Push("item"))
+	}
+
+	var counts []int
+	for _, p := range mockedPushers {
+		counts = append(counts, p.count)
+	}
+	mean := calcMean(counts)
+	variance := calcVariance(mean, counts)
+	assert.True(t, variance < 100, fmt.Sprintf("too big variance - %.2f", variance))
+}
+
+func TestBalancedQueuePusher_NoAvailable(t *testing.T) {
+	pusher := NewBalancedQueuePusher(nil)
+	assert.True(t, len(pusher.Name()) == 0)
+	assert.Equal(t, ErrNoAvailablePusher, pusher.Push("item"))
+}