drug testing at working interview?

hi all! went in for a job interview today at an animal hospital and was asked to come in for a working interview tomorrow. they mentioned a pre-employment drug screening. should i expect this before the interview or after, or a different day entirely? would be my first time in a field like this, don’t want to not be considered just because i smoked weed semi-recently. any help would be super appreciated, thank you!

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