Implement Stomp 1.2 value encoding

Add unit tests for escape/unescape methods

mq/main/bridge/bridge-api/src/test/java/com/sun/messaging/bridge/api/StompFrameMessageTest.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2022 Contributors to the Eclipse Foundation
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0, which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the
+ * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
+ * version 2 with the GNU Classpath Exception, which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ */
+
+package com.sun.messaging.bridge.api;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class StompFrameMessageTest {
+
+    /*
+     * "All frames except the CONNECT and CONNECTED frames will also escape any carriage return, line feed or colon
+     * found in the resulting UTF-8 encoded headers."
+     * - https://stomp.github.io/stomp-specification-1.2.html#Value_Encoding
+     */
+    @Test
+    void unescapeSpecialChars() {
+        // carriage return, line feed, colon and backslash
+        assertEquals("\r\n:\\", StompFrameMessage.unescapeSpecialChars("\\r\\n\\c\\\\"));
+
+        // opposite order
+        assertEquals("\\:\n\r", StompFrameMessage.unescapeSpecialChars("\\\\\\c\\n\\r"));
+
+        // real world examples
+        assertEquals("c:\\Users", StompFrameMessage.unescapeSpecialChars("c\\c\\\\Users"));
+        assertEquals("http:\\\\server:port", StompFrameMessage.unescapeSpecialChars("http\\c\\\\\\\\server\\cport"));
+    }
+
+    @Test
+    void escapeSpecialChars() {
+        // carriage return, line feed, colon and backslash
+        assertEquals("\\r\\n\\c\\\\", StompFrameMessage.escapeSpecialChars("\r\n:\\"));
+
+        // opposite order
+        assertEquals("\\\\\\c\\n\\r", StompFrameMessage.escapeSpecialChars("\\:\n\r"));
+
+        // real world examples
+        assertEquals("c\\c\\\\Users", StompFrameMessage.escapeSpecialChars("c:\\Users"));
+        assertEquals("http\\c\\\\\\\\server\\cport", StompFrameMessage.escapeSpecialChars("http:\\\\server:port"));
+    }
+}