Add tests

pom.xml

@@ -20,9 +20,9 @@
             <version>20240303</version>
         </dependency>
         <dependency>
-            <groupId>junit</groupId>
-            <artifactId>junit</artifactId>
-            <version>4.13.2</version>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <version>5.9.2</version>
             <scope>test</scope>
         </dependency>
     </dependencies>

src/main/java/com/yocto/yoclib/jsonrpc/JSONRPCException.java

@@ -2,4 +2,8 @@
 
 public class JSONRPCException extends Exception{
 
+    public JSONRPCException(String message){
+        super(message);
+    }
+
 }

src/main/java/com/yocto/yoclib/jsonrpc/Message.java

@@ -1,6 +1,6 @@
 package com.yocto.yoclib.jsonrpc;
 
-import org.json.JSONObject;
+import org.json.*;
 
 public abstract class Message{
 
@@ -61,4 +61,38 @@ public JSONObject toObject(){
         return this.value;
     }
 
+    /**
+     *
+     * @param object The object
+     * @return JSON string
+     * @throws JSONRPCException An exception
+     */
+    public static String encodeJSON(Object object) throws JSONRPCException {
+        try{
+            if(object instanceof JSONObject){
+                return ((JSONObject) object).toString(0);
+            }
+            if(object instanceof JSONArray){
+                return ((JSONArray) object).toString(0);
+            }
+            return JSONObject.valueToString(object);
+        }catch(JSONException e){
+            throw new JSONRPCException("Failed to encode JSON.");
+        }
+    }
+
+    /**
+     *
+     * @param json JSON string
+     * @return The object
+     * @throws JSONRPCException An exception
+     */
+    public static Object decodeJSON(String json) throws JSONRPCException {
+        try{
+            return new JSONTokener(json).nextValue();
+        }catch(JSONException $e){
+            throw new JSONRPCException("Failed to decode JSON.");
+        }
+    }
+
 }

src/test/java/com/yocto/yoclib/jsonrpc/tests/MessageTest.java

@@ -1,7 +1,23 @@
 package com.yocto.yoclib.jsonrpc.tests;
 
-import junit.framework.TestCase;
+import com.yocto.yoclib.jsonrpc.JSONRPCException;
+import com.yocto.yoclib.jsonrpc.Message;
 
-public class MessageTest extends TestCase{
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+public class MessageTest{
+
+    @Test
+    public void testDecodeEmptyJSON(){
+        Throwable t = assertThrows(JSONRPCException.class,() -> Message.decodeJSON(""));
+
+        assertEquals("Failed to decode JSON.",t.getMessage());
+    }
+
+    @Test
+    public void testDecodeJSONString() throws JSONRPCException {
+        assertEquals("abc",Message.decodeJSON("\"abc\""));
+    }
 
 }