Add JSON deserialization test

Author: 134130

mcp/src/test/java/io/modelcontextprotocol/spec/McpSchemaTests.java

@@ -185,6 +185,24 @@ void testJSONRPCRequest() throws Exception {
 					{"jsonrpc":"2.0","method":"method_name","id":1,"params":{"key":"value"}}"""));
 	}
 
+	@Test
+	void testJSONRPCRequestWithMeta() throws Exception {
+		Map<String, Object> params = new HashMap<>();
+		params.put("key", "value");
+		params.put("_meta", Map.of("progressToken", "abc123"));
+
+		McpSchema.JSONRPCRequest request = new McpSchema.JSONRPCRequest(McpSchema.JSONRPC_VERSION, "method_name", 1,
+				params);
+
+		String value = mapper.writeValueAsString(request);
+		assertThatJson(value).when(Option.IGNORING_ARRAY_ORDER)
+			.when(Option.IGNORING_EXTRA_ARRAY_ITEMS)
+			.isObject()
+			.isEqualTo(
+					json("""
+							{"jsonrpc":"2.0","method":"method_name","id":1,"params":{"key":"value"},"_meta":{"progressToken":"abc123"}}"""));
+	}
+
 	@Test
 	void testJSONRPCNotification() throws Exception {
 		Map<String, Object> params = new HashMap<>();