lease: add "TestLeaseQueue"

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

lease/lease_queue_test.go

@@ -0,0 +1,44 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package lease
+
+import (
+	"container/heap"
+	"testing"
+	"time"
+)
+
+func TestLeaseQueue(t *testing.T) {
+	le := &lessor{
+		leaseHeap: make(LeaseQueue, 0),
+		leaseMap:  make(map[LeaseID]*Lease),
+	}
+	heap.Init(&le.leaseHeap)
+
+	// insert in reverse order of expiration time
+	for i := 50; i >= 1; i-- {
+		exp := time.Now().Add(time.Hour).UnixNano()
+		if i == 1 {
+			exp = time.Now().UnixNano()
+		}
+		le.leaseMap[LeaseID(i)] = &Lease{ID: LeaseID(i)}
+		heap.Push(&le.leaseHeap, &LeaseWithTime{id: LeaseID(i), expiration: exp})
+	}
+
+	// first element must be front
+	if le.leaseHeap[0].id != LeaseID(1) {
+		t.Fatalf("first item expected lease ID %d, got %d", LeaseID(1), le.leaseHeap[0].id)
+	}
+}