estimate the defect before performing the testing

i think the question  is debugging or bug?
debugging is the process of finding the errors in the 
automated script and resolving it.
bug is the diffenrence between expected value and actual 
value.

If the Project management add some known defects inorder to
estimate the efficiency of tester,then it is called Be
bugging or Defect Seeding or Defect Feeding.

The process of intentionally adding known defects to those 
already in the
component or system for the purpose of monitoring the rate 
of detection and removal, and
estimating the number of remaining defects. [IEEE 610]

In simple words, "Be bugging" is the process of adding 
known defects to the application by seeding

bugging : to irritate or upset 

Be bugging : It is a process of adding known defect/s with
an intention to disturb application/software working , It
can be done through seeding.

In short :- Adding known defects by seeding