04 Re-Testing & Regression Testing (v2.5)

© SIM Group Ltd., SQS Group AG, 2002

ISEB Foundation Certificate in Software Testing

Re-Testing & Regression TestingRe-Testing & Regression Testing


Re-Testing & Regression Testing

In this session we willIn this session we will

Understand how fault fixing and re-testing are key to the Understand how fault fixing and re-testing are key to the overall testing processoverall testing process

Look at how test repeatability helpsLook at how test repeatability helps

Understand what regression testing is and where it fits inUnderstand what regression testing is and where it fits in

Understand how to select test cases for regression testingUnderstand how to select test cases for regression testing


Re-Testing

Testing is directed at finding faultsTesting is directed at finding faults

These faults will need to be corrected and a new version of These faults will need to be corrected and a new version of the software releasedthe software released

The tests will need to be run again to prove that the fault is The tests will need to be run again to prove that the fault is fixedfixed

This is known as Re-TestingThis is known as Re-Testing


Re-Testing

The need for re-testing needs to be planned & The need for re-testing needs to be planned & designed fordesigned for

Schedules need to allow for re-testingSchedules need to allow for re-testing

Tests need to be easily re-runTests need to be easily re-run

The environment needs to be easily restoredThe environment needs to be easily restored


Regression Testing

““Re-testing of a previously tested program following Re-testing of a previously tested program following modification to ensure that FAULTS have not been modification to ensure that FAULTS have not been introduced or uncovered as a result of the changes introduced or uncovered as a result of the changes made” made”


Regression Testing

Module 14 v1.4.2

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Declare String x =Date();~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Module 41 v1.8.9

~~~~~~~~~~~~~~~~Declare Integer x = 0;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~For x = 1 to 5~~~~~~~~~~~~~~~~

Module 93 v1.3.5

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Print (x);~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Module 14 v1.4.3

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Global String x = Date();~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

How can you fix this but break

that?


Regression Testing

Tests will also need to be re-run when checking Tests will also need to be re-run when checking software upgradessoftware upgrades

Regression tests should be run whenever there is a change Regression tests should be run whenever there is a change to the software or the environmentto the software or the environment

Regression tests are executed to prove aspects of a system Regression tests are executed to prove aspects of a system have not changedhave not changed

Regression Testing is a vital testing techniqueRegression Testing is a vital testing technique


Regression Testing

Selecting cases for regression:Selecting cases for regression:

Tests that cover safety or business critical functionsTests that cover safety or business critical functions

Tests that are repetitiveTests that are repetitive

Tests that need accurate dataTests that need accurate data

Tests for areas that change regularlyTests for areas that change regularly

Tests of functions that have a high level of defectsTests of functions that have a high level of defects


Regression Testing

Regression Testing is the ideal foundation for Regression Testing is the ideal foundation for AutomationAutomation

Selecting test cases is vital, and requires a degree of Selecting test cases is vital, and requires a degree of knowledge of the applications and their expected evolutionknowledge of the applications and their expected evolution


Re-Testing & Regression Testing

SummarySummary

Once a fault has been fixed the software MUST be re-testedOnce a fault has been fixed the software MUST be re-tested New faults may have been introduced by the fixNew faults may have been introduced by the fix Existing faults may have been uncovered by the fixExisting faults may have been uncovered by the fix Tests need to be written to enable their re-useTests need to be written to enable their re-use

Re-testing is the rerunning of failed tests once a fix has been Re-testing is the rerunning of failed tests once a fix has been implemented to check that the fix has workedimplemented to check that the fix has worked

Regression testing is running of a wider test suite to check for Regression testing is running of a wider test suite to check for unexpected errors in unchanged codeunexpected errors in unchanged code

Documents

04 Re-Testing & Regression Testing (v2.5)