Honestly dude if you passed the walgreens test you should be good on the employment test. The walgreens tests are usually pretty accurate so I don't think that would be a problem. It would prolly cost the employer a hell of a lot of money to get a more accurate test than that. Unless you're applying for a job as an astronaut or professional athlete, then I HIGHLY doubt your employer would go through the extra expense. There is just no way that an employer would risk hundreds of dollars on some crazy test if he doesn't even know if you're even a good employee.

Just don't worry man. It's all gonna be good.