Regression testing:

Re execution of a selected test case on modified build to 
ensure bug fix work and occurances of side effects is 
called regression test.

Retesting:

Re executing the same test more than one time with multiple 
test data.it is also called iterative or re-testing.


For Example: There are 10 testcases to be passed for a 
requirement. But 10th testcase failed and tester raised a 
defect in the defect log.

Retesting: After the above defect is fixed, tester need to 
execute the 10th testcase to check the expected result for 
the same.

Regression Testing: After the above defect is fixed, tester 
need to execute the 20% of above testcases by selecting 
randomly to make sure that existing functionality is not 
broken because of the above fix.

Vidya is absolutely correct with her answer above !

I FEEL THAT BOTH REGREESION AND RE TESTING ARE SAME

regression testing:
     regression testing means reported bug is resolved or 
not this is called regression testing.
retesting means to test diffrent combinaions of data i,e 
called retesting testing.....

Regression Testing:Whenever there is a change/modification 
in the code of an application may be due to change in 
requirement or bug fixing the testing carried out in this 
event to avow that application is not behaving in an 
aberrant manner is called regression testing.

Re-testing:This testing is done with both positive and 
negative inputs i.e. executing one fuctional test case with 
different sets of data.

Plz correct me if i'm wrong

Shijath Ali
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