diff --git a/apps/foo/src/main/java/org/onlab/onos/foo/TestMessage.java b/apps/foo/src/main/java/org/onlab/onos/foo/TestMessage.java
new file mode 100644
index 0000000..b6f1768
--- /dev/null
+++ b/apps/foo/src/main/java/org/onlab/onos/foo/TestMessage.java
@@ -0,0 +1,41 @@
+package org.onlab.onos.foo;
+
+import org.onlab.nio.AbstractMessage;
+
+/**
+ * Fixed-length message.
+ */
+public class TestMessage extends AbstractMessage {
+
+    private final byte[] data;
+
+    /**
+     * Creates a new message with the specified length.
+     *
+     * @param length message length
+     */
+    public TestMessage(int length) {
+        this.length = length;
+        data = new byte[length];
+    }
+
+    /**
+     * Creates a new message with the specified data.
+     *
+     * @param data message data
+     */
+    TestMessage(byte[] data) {
+        this.length = data.length;
+        this.data = data;
+    }
+
+    /**
+     * Gets the backing byte array data.
+     *
+     * @return backing byte array
+     */
+    public byte[] data() {
+        return data;
+    }
+
+}