initial import

core/stat/topk_test.go

@@ -0,0 +1,62 @@
+package stat
+
+import (
+	"math/rand"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+const (
+	numSamples = 10000
+	topNum     = 100
+)
+
+var samples []Task
+
+func init() {
+	for i := 0; i < numSamples; i++ {
+		task := Task{
+			Duration: time.Duration(rand.Int63()),
+		}
+		samples = append(samples, task)
+	}
+}
+
+func TestTopK(t *testing.T) {
+	tasks := []Task{
+		{false, 1, "a"},
+		{false, 4, "a"},
+		{false, 2, "a"},
+		{false, 5, "a"},
+		{false, 9, "a"},
+		{false, 10, "a"},
+		{false, 12, "a"},
+		{false, 3, "a"},
+		{false, 6, "a"},
+		{false, 11, "a"},
+		{false, 8, "a"},
+	}
+
+	result := topK(tasks, 3)
+	if len(result) != 3 {
+		t.Fail()
+	}
+
+	set := make(map[time.Duration]struct{})
+	for _, each := range result {
+		set[each.Duration] = struct{}{}
+	}
+
+	for _, v := range []time.Duration{10, 11, 12} {
+		_, ok := set[v]
+		assert.True(t, ok)
+	}
+}
+
+func BenchmarkTopkHeap(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		topK(samples, topNum)
+	}
+}