If i have tested positive for covid-19 but have no symptoms how do i know when i have recovered. would i need to retest after 14 days?

Hard to be specific: Many work places require you have 2 negative tests at least a day apart before allowing you to return to work. I would check with a local health authority or your workplace for their guidance.

COVID-19 Recovery: COVID-19 patients may discontinue isolation if at least 10 days have passed since symptoms first appeared (or positive test if asymptomatic) AND at least 24 hours with no fever without fever-reducing medication AND improvement of symptoms. Alternatively may stop isolation if no fever, respiratory symptoms have improved, and two negative test results in a row, at least 24 hours apart.