KAFKA-2121; add missing file

clients/src/test/java/org/apache/kafka/test/MockSerializer.java

@@ -0,0 +1,46 @@
+/**
+ * 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.kafka.test;
+
+import org.apache.kafka.common.serialization.Serializer;
+
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class MockSerializer implements Serializer<byte[]> {
+    public static final AtomicInteger INIT_COUNT = new AtomicInteger(0);
+    public static final AtomicInteger CLOSE_COUNT = new AtomicInteger(0);
+
+    public MockSerializer() {
+        INIT_COUNT.incrementAndGet();
+    }
+
+    @Override
+    public void configure(Map<String, ?> configs, boolean isKey) {
+
+    }
+
+    @Override
+    public byte[] serialize(String topic, byte[] data) {
+        return data;
+    }
+
+    @Override
+    public void close() {
+        CLOSE_COUNT.incrementAndGet();
+    }
+}