Regression Testing

 Definition of Regression Testing
Re execution of the same test cases in different releases ,just to ensure changes
(addition,deletion,modification or bug fixing) will not have any impact on the
unchanged features.


Explanation of Regression Testing


When development team is developing the application,Test engineers
will be writing the test cases ,say around 1000.When application is
developed ,Test engineer will do testing by executing those 1000 test cases.

Later when customer gives new feature,developer will develop the new
feature and Test engineer  will be writing the new test cases,
After application developer,Test engineer will test the application say
around 200 test cases and will execute previous 1000 test cases to
ensure that adding new feature has not affected old feature.So executing
1000 test again  is called Regression Testing.

          Types of Regression Testing
       
         1)Unit regression Testing
            Testing is done only on the defect  fixed and not execute other
            test cases since it has no impact on other features.
        
         2)Regional Regression Testing?

• Re execute all test cases only on the regions that have impact due to defect.
• Depending on impact analysis Re execution is done.
• Whole application is not executed once again.

        
          3)Full Regression

• If we do all modifications ,addition,deletion then surely
  impact will be a on the whole application.
• If more changes are done then full regression testing is done. 
   
  Drawbacks of Regression testing
  
• Repeatedly when we regression, chances are there we may
  miss lot of bugs and there will no consistency in testing ,
  that means ,when we do repeatedly testing on one feature ,
  test engineers will miss other features and from that many bugs.
   
• Due to regression the automation comes in to picture.
  We need to execute test case  again and again in different
  release which become monotonous(Doing the same work again and again)
  hence  regression  testing are automated.

•     Test execution takes more time.
  
  Regression testing is a bridge between manual and
  automation