[ROCKETMQ-255] Fix offsetStore being null after consumers start()

Author: Li Zhanhui <lizhanhui@gmail.com>

Closes #142 from lizhanhui/offset_store.

client/src/main/java/org/apache/rocketmq/client/impl/consumer/DefaultMQPullConsumerImpl.java

@@ -569,6 +569,7 @@ public class DefaultMQPullConsumerImpl implements MQConsumerInner {
                         default:
                             break;
                     }
+                    this.defaultMQPullConsumer.setOffsetStore(this.offsetStore);
                 }
 
                 this.offsetStore.load();

client/src/main/java/org/apache/rocketmq/client/impl/consumer/DefaultMQPushConsumerImpl.java

@@ -577,6 +577,7 @@ public class DefaultMQPushConsumerImpl implements MQConsumerInner {
                         default:
                             break;
                     }
+                    this.defaultMQPushConsumer.setOffsetStore(this.offsetStore);
                 }
                 this.offsetStore.load();
 

client/src/test/java/org/apache/rocketmq/client/consumer/DefaultMQPullConsumerTest.java

@@ -32,6 +32,7 @@ import org.apache.rocketmq.common.message.MessageExt;
 import org.apache.rocketmq.common.message.MessageQueue;
 import org.apache.rocketmq.common.protocol.header.PullMessageRequestHeader;
 import org.junit.After;
+import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -83,6 +84,11 @@ public class DefaultMQPullConsumerTest {
         pullConsumer.shutdown();
     }
 
+    @Test
+    public void testStart_OffsetShouldNotNUllAfterStart() {
+        Assert.assertNotNull(pullConsumer.getOffsetStore());
+    }
+
     @Test
     public void testPullMessage_Success() throws Exception {
         doAnswer(new Answer() {

client/src/test/java/org/apache/rocketmq/client/consumer/DefaultMQPushConsumerTest.java

@@ -52,6 +52,7 @@ import org.apache.rocketmq.common.message.MessageQueue;
 import org.apache.rocketmq.common.protocol.header.PullMessageRequestHeader;
 import org.apache.rocketmq.remoting.exception.RemotingException;
 import org.junit.After;
+import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -155,6 +156,11 @@ public class DefaultMQPushConsumerTest {
         pushConsumer.shutdown();
     }
 
+    @Test
+    public void testStart_OffsetShouldNotNUllAfterStart() {
+        Assert.assertNotNull(pushConsumer.getOffsetStore());
+    }
+
     @Test
     public void testPullMessage_Success() throws InterruptedException, RemotingException, MQBrokerException {
         final CountDownLatch countDownLatch = new CountDownLatch(1);