The sobriety tests isn't a test, its a ploy to get you to incriminate yourself and give the cop evidence for court. Never agree to the tests.
A lawyer friend of mine told me of a case in which the cop's dash board recording was brought into court by the defense to show that the driver never swerved as the cop claimed. The Judge saw the evidence and simply didn't care.
Laws vary in different states but never admitting to drinking anything is the first line of defense. Also, there are other tricks you can learn about on line. If you get a fair judge these can help - if you get a Nazi maybe not.
Also know that cops have special flashlights that sniff alcohol so you want to roll down the windows prior to stopping crank the air and answer yes or no only.
And never under any circumstances be fooled into advocating your own loss of liberty like 90% of the idiots out there.
link please.