Simply having a large beta test cannot consistently provide stability and performance to game servers, which are major issues in online game development. Therefore, test automations have been used in order to reduce the testing time of online games by simulating highly repetitive tasks and emulating server loads. However, in previous approaches, black box testing and scenario-based testing are not supported because they use prerecorded packets of real players as templates, or reuse a subset of the main game client for the test client. In this paper, we propose black box testing and scenario-based testing of online games as well as simple load testing. Instead of rewriting the virtual client dummy code, only the game description language and virtual game map are redefined when a new game is to be tested. In addition, an actual testing environment can be mimicked more closely, because complex and various scenarios such as attack, party play, and waypoint movement can be tested through combining actions. We have applied our tools on several online games to verify the effectiveness of our method.