How to capture Execution time of tests

You can see the run time in the test log :

If you need to get the run time as a value, please check this topic: https://support.smartbear.com/viewarticle/68946/

you could assign to a variable the "Now" value (system datetime) twice, once at the begining of the test and the other at the end (assuming you don't change within the test the system date...) and make substraction and appropriate conversion.