Big difference is that debugging is conducted by a programmer and the programmer fix the errors during debugging phase. Tester never fixes the errors, but rather find them and return to programmer.
debugging done in the devlopment phase by the devlopers.
testing is conducted by the testers in testing phase.
in devlopment phase devloper fixes the bug (i.e)called debugging
in testing phase tester will finds the bug (i.e)called testing to improve the quality of the product
Debugging is a process of line by line execution(White Box Testing) of the code/ script with the intent of finding errors/ fixing the defects. Testing is a process of finding the defects from a user perspective(Black Box Testing).
Testing is what the testers test an application and when some bugs found will report to the developers. Debugging is done by the developers, here they make some changes in the code in case of any error in the code.