Drug Test Help

I've looked all over and haven't found any solid advice, which is why I'm here. I tried posting this a minute ago and it didn't show up so if this is a double post, I apologize...

Lasix: does this work? Is it safe? When do you take it? And do you think a generic version online would be safe?
Cleansers: which ones are good and where can I get them? I heard "the strip" was a good cleanser, but I dont know where to get it nor do I know if it's actually efficient.
Aspirin: does this really throw off drug tests? How many do I take and when do I take them?
Water: I understand you can overdose, but I'm not a fucking idiot and I'm not going to overdose. But some have said it works, some have said it's pointless, and some have said there's no evidence to either. Is it pointless to start drinking lots of water days before your test? Or is it only effective the day of (and maybe before). I'm aware that I need B vitamins and creatine as well.
Niacin: seriously, I just want a straight answer on this one. Yes or no
Visine: now this sounds crazy, but I read a few drops of visine into your cup might throw off the test. What's the deal with this theory?
Exercise: I've also heard this can be useless. I've also heard theres a window of opportunity, so to speak. When should you be exercising and is it bad the day of and before your test?
Using someone else's urine: is this really as easy as it sounds? What's the best way to do it and how do you not get caught? I feel like it'd be way obvious...

Here's some background:
I'm 6'2", 200 pounds or so. Pretty lean, but not very physically active. I recently got a new bike and have been biking about 10 miles a day. I'm a heavy smoker, I would say. I've had some big smoking nights/weekends recently and have smoked every day this week. Sometimes once, most times multiple times a day.

Today I saw a notice on the time sheet that "Drug testing begins next week." They tried this in the fall and failed miserably. I'm pretty sure most people didn't do it and they didn't question it. They're aware of a few employees who smoke weed, though not on the job. No one comes to work high, as far as I know. The workers who do smoke are some of the best employees there. Not only are we struggling to get fully staffed, but they're struggling financially, so drug testing seems like a stupid fucking idea to me (though I believe it's always ridiculous. I'm sorry, sir, despite being a model employee with unparalleled efficiency and performance, we're looking for employees whose THC levels don't exceed their red bloodcell count. You're fired.)

I don't know how the tests will be administered. There was nothing in the application when I applied and nothing in the employee handbook during orientation. But it's an at-will employment and Illinois is a no-reason state. So I can be fired and there's nothing I can do about it. I would guess we're doing urine tests and we'll be given an hour to drive ourselves to somewhere to get the drug test.

I have a great relationship with my boss. Honestly, I'm one of the best employees. I've been told that by my director and coworkers. I'm conflicted. Should I be honest beforehand? Challenge it beforehand? Or try to beat it first and if I fail should I try to talk my way out of it somehow (which I would say is possible. I do a lot for my employers and us toking employees are banding together. We'll fight for each other.) Maybe honesty isn't the best, but I could lie and say someone sprinkled weed on the shisha in a hookah and I wasn't aware, thus the failed test. Or something.

I'm tweaking and I need advice. Fast. I don't know how long I have before the test.

 

Is there anything I can get at GNC or VitaminShoppe?
Where can I get a 3 day or 7 day cleanse or something?