add tests for AllocateMessageQueueAveragely (#3811)

Author: yuz10

client/src/test/java/org/apache/rocketmq/client/consumer/rebalance/AllocateMessageQueueAveragelyTest.java

@@ -0,0 +1,57 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.rocketmq.client.consumer.rebalance;
+
+import junit.framework.TestCase;
+import org.apache.rocketmq.common.message.MessageQueue;
+import org.junit.Assert;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class AllocateMessageQueueAveragelyTest extends TestCase {
+
+    public void testAllocateMessageQueueAveragely() {
+        List<String> consumerIdList = createConsumerIdList(4);
+        List<MessageQueue> messageQueueList = createMessageQueueList(10);
+        int[] results = new int[consumerIdList.size()];
+        for (int i = 0; i < consumerIdList.size(); i++) {
+            List<MessageQueue> result = new AllocateMessageQueueAveragely().allocate("", consumerIdList.get(i), messageQueueList, consumerIdList);
+            results[i] = result.size();
+        }
+        Assert.assertArrayEquals(new int[]{3, 3, 2, 2}, results);
+    }
+
+    private List<String> createConsumerIdList(int size) {
+        List<String> consumerIdList = new ArrayList<String>(size);
+        for (int i = 0; i < size; i++) {
+            consumerIdList.add("CID_PREFIX" + i);
+        }
+        return consumerIdList;
+    }
+
+    private List<MessageQueue> createMessageQueueList(int size) {
+        List<MessageQueue> messageQueueList = new ArrayList<MessageQueue>(size);
+        for (int i = 0; i < size; i++) {
+            MessageQueue mq = new MessageQueue("topic", "brokerName", i);
+            messageQueueList.add(mq);
+        }
+        return messageQueueList;
+    }
+
+
+}