static void Main(string[] args) { var tester = new MediaTester(); var mp3 = new MP3player(); var mp4 = new MP4Player(); var mp3Delegate = new MediaTester.TestMedia(mp3.PlayMP3File); var mp4Delegate = new MediaTester.TestMedia(mp4.PlayMP4File); tester.runTest(mp3Delegate); tester.runTest(mp4Delegate); }