Further, failure to succeed would likely spell an end to the expected effort to recall Wisconsin Gov. Scott Walker next year once he completes his first full year in office.
Wozniacki's failure to capture a grand slam title during her spell at the top of the world rankings meant she faced constant questioning on the subject.
Failure of a test usually means an instant short spell in jail, and it is hoped that such a dramatic sentence will shock people out of re-offending - thereby reducing long-term prison numbers and cutting off alcohol-related crime at the source.