[lldb] Add more tests MCP protocol types

Add unit testing for the different message types.

(cherry picked from commit 7e3af67)

Author: JDevlieghere

lldb/unittests/Protocol/ProtocolMCPTest.cpp

@@ -133,3 +133,100 @@ TEST(ProtocolMCPTest, ToolDefinition) {
   EXPECT_EQ(tool_definition.inputSchema,
             deserialized_tool_definition->inputSchema);
 }
+
+TEST(ProtocolMCPTest, MessageWithRequest) {
+  Request request;
+  request.id = 1;
+  request.method = "test_method";
+  request.params = llvm::json::Object{{"param", "value"}};
+
+  Message message = request;
+
+  llvm::Expected<Message> deserialized_message = roundtripJSON(message);
+  ASSERT_THAT_EXPECTED(deserialized_message, llvm::Succeeded());
+
+  ASSERT_TRUE(std::holds_alternative<Request>(*deserialized_message));
+  const Request &deserialized_request =
+      std::get<Request>(*deserialized_message);
+
+  EXPECT_EQ(request.id, deserialized_request.id);
+  EXPECT_EQ(request.method, deserialized_request.method);
+  EXPECT_EQ(request.params, deserialized_request.params);
+}
+
+TEST(ProtocolMCPTest, MessageWithResponse) {
+  Response response;
+  response.id = 2;
+  response.result = llvm::json::Object{{"result", "success"}};
+
+  Message message = response;
+
+  llvm::Expected<Message> deserialized_message = roundtripJSON(message);
+  ASSERT_THAT_EXPECTED(deserialized_message, llvm::Succeeded());
+
+  ASSERT_TRUE(std::holds_alternative<Response>(*deserialized_message));
+  const Response &deserialized_response =
+      std::get<Response>(*deserialized_message);
+
+  EXPECT_EQ(response.id, deserialized_response.id);
+  EXPECT_EQ(response.result, deserialized_response.result);
+}
+
+TEST(ProtocolMCPTest, MessageWithNotification) {
+  Notification notification;
+  notification.method = "notification_method";
+  notification.params = llvm::json::Object{{"notify", "data"}};
+
+  Message message = notification;
+
+  llvm::Expected<Message> deserialized_message = roundtripJSON(message);
+  ASSERT_THAT_EXPECTED(deserialized_message, llvm::Succeeded());
+
+  ASSERT_TRUE(std::holds_alternative<Notification>(*deserialized_message));
+  const Notification &deserialized_notification =
+      std::get<Notification>(*deserialized_message);
+
+  EXPECT_EQ(notification.method, deserialized_notification.method);
+  EXPECT_EQ(notification.params, deserialized_notification.params);
+}
+
+TEST(ProtocolMCPTest, MessageWithError) {
+  ErrorInfo error_info;
+  error_info.code = -32603;
+  error_info.message = "Internal error";
+
+  Error error;
+  error.id = 3;
+  error.error = error_info;
+
+  Message message = error;
+
+  llvm::Expected<Message> deserialized_message = roundtripJSON(message);
+  ASSERT_THAT_EXPECTED(deserialized_message, llvm::Succeeded());
+
+  ASSERT_TRUE(std::holds_alternative<Error>(*deserialized_message));
+  const Error &deserialized_error = std::get<Error>(*deserialized_message);
+
+  EXPECT_EQ(error.id, deserialized_error.id);
+  EXPECT_EQ(error.error.code, deserialized_error.error.code);
+  EXPECT_EQ(error.error.message, deserialized_error.error.message);
+}
+
+TEST(ProtocolMCPTest, ResponseWithError) {
+  ErrorInfo error_info;
+  error_info.code = -32700;
+  error_info.message = "Parse error";
+
+  Response response;
+  response.id = 4;
+  response.error = error_info;
+
+  llvm::Expected<Response> deserialized_response = roundtripJSON(response);
+  ASSERT_THAT_EXPECTED(deserialized_response, llvm::Succeeded());
+
+  EXPECT_EQ(response.id, deserialized_response->id);
+  EXPECT_FALSE(deserialized_response->result.has_value());
+  ASSERT_TRUE(deserialized_response->error.has_value());
+  EXPECT_EQ(response.error->code, deserialized_response->error->code);
+  EXPECT_EQ(response.error->message, deserialized_response->error->message);
+}