Just had a hair test

So i had a hair test yesterday, use to smoke once a week up until about 6-7 weeks ago realised i would be in for a test.
I had my hair shaved down to a grade one about 4 weeks ago. They took it from my head, ive got about 1cm on there now.
Is there a high chance im going to fail or am i likely to pass?

Thanks

They took hair from your head that is only 1cm in length?

Yeah buddy im from the UK, pre-employment. Not too sure if the hair would have been drug free as i had 3mm left when it was cut.