Regression Testing

Usage:


• All aspects of system remain functional after testing.
  
• Change in one segment does not change the functionality of other segment.

Objective:


• Determine System documents remain current
• Determine System test data and test conditions remain current
• Determine Previously tested system functions properly without getting effected though changes are made in some other segment of application system.

How to Use


• Test cases, which were used previously for the already tested segment is, re-run to ensure that the results of the segment tested currently and the results of same segment tested earlier are same.
• Test automation is needed to carry out the test transactions (test condition execution) else the process is very time consuming and tedious.
• In this case of testing cost/benefit should be carefully evaluated else the efforts spend on testing would be more and payback would be minimum.

When to Use


• When there is high risk that the new changes may effect the unchanged areas of application system.
• In development process: Regression testing should be carried out after the pre-determined changes are incorporated in the application system.
• In Maintenance phase : regression testing should be carried out if there is a high risk that loss may occur when the changes are made to the system

Example


• Re-running of previously conducted tests to ensure that the unchanged portion of system functions properly.
• Reviewing previously prepared system documents (manuals) to ensure that they do not get effected after changes are made to the application system.

Disadvantage


• Time consuming and tedious if test automation not done