PDA test - Engine Light

I will have my PDA at 10am tomorrow. My car suddenly has an idea to put the engine light on.

Mate has a scanner and did try to erase the code. It worked but I just realised when driving back home that it comes up again. The code is O2 sensor, which is not so urgent to get it replaced, he said.

I can see from the DoT website that engine light on, meaning no roadworthy, meaning cant do test. But what if my mate erased the code before the test, but it turned on during the PDA. Would it be an auto fail?

Thanks so much!