You are under no obligation whatsoever to perform any physical tests like watching a pen, balancing on one leg, or walking a line. There is no legal penalty for refusing those tests. Don’t fall for a line like “Well, if you refuse to do the tests, you’re giving me no choice but to arrest you”. You may be arrested when you refuse, but the officer really decided to arrest you before he asked you to do the tests. Politely and respectfully declining to do any tests prior to consulting with an attorney will go a long way to helping your defense.
You have never performed the tests that he is requesting. Regardless of how well you think you will do on the tests, you will learn you failed the tests. Even officers who have done the tests hundreds of times fail to administer the tests by the book. When the officer asks you to perform for him, politely state that you must speak to an attorney before deciding whether to perform any test.