If you come into contact with someone that has COVID-19 you must quarantine for 14 days if you test positive how long must you quarantine?

I think it is until after you get two negative test results,  however long that takes.  

If you test positive, no matter how many days you have quarantined, you still have to continue quarantining 

It’s 10 days, correct, but repeat testing is not recommended by the CDC.  Go to their web site.

If you have CLOSE CONTACT with someone who is infected with covid, you need to quarantine for 7 days and then a negative test or 10 days with a negative test.
- close contact is defined at within 6ft for 15minutes within a 24hour period.

If you have casual contact, you don't need to quarantine.

If you test positive for covid, you need to quarantine for 10 days after the contact occured.  If you don't know when the contact occurred, you need to quarantine for 10 days or until you get a negative test, whichever is shorter.

The 14 day period is no longer used. 

probably 14 days