What is A/B test?
An A/B test randomly splits visitors between two versions of a page, price or offer and compares an outcome such as profit per visitor.
Random assignment is what separates a test from a before and after comparison. Decide the outcome and the run time before you start, and do not stop the moment one version looks ahead.
A test needs enough orders in each group to tell a real difference from noise; small stores often have to run longer or test bigger changes.