Introduction to Regression Testing
Regression testing is any type of software testing that seeks to uncover software errors by partially retesting a modified program.
The intent of regression testing is to assure that a bug fix has been successfully corrected based on the error that was found while providing a general assurance that no other errors were introduced in the process of fixing the original problem.
Regression is commonly used to efficiently test bug fixes by systematically selecting the appropriate minimum test suite needed to adequately cover the affected software code/requirements change. Common methods of regression testing include rerunning previously run tests and checking whether previously fixed faults have re-emerged.
so the bottom line is if due to any code got change or introduced into the exiting program…. there is always a chance that a bug may be introduced into the system. adding a new feature (changing code or adding extra system) is termed as regression.
hence Regression testing is the process of testing changes to computer programs to make sure that the older programming still works with the new changes.
The selective retesting of a software system that has been modified to ensure that any bugs have been fixed and that no other previously working functions have failed as a result of the reparations and that newly added features have not created problems with previous versions of the software.
Also referred to as verification testing, regression testing is initiated after a programmer has attempted to fix a recognized problem or has added source code to a program that may have inadvertently introduced errors. It is a quality
control measure to ensure that the newly modified code still complies with its specified requirements and that unmodified code has not been affected by the maintenance activity.
The variety of application screening approach that is performed following the implementation of new features or modification of the present operation is identified as regression tests. Its goal is to be certain that all variations of the code do not evoke any aspect effects and interrupt the appropriate procedure of the full program and its parts.
Regression screening is also executed immediately after selected bugs have been preset. It is carried out for verifying that the challenges have been entirely eliminated. Besides that, the course of action of bug repairing ought to not impact anyhow the present functionalities.
To effectively accomplish the course of action of software package products immediately after any adjustments or modifications, several methods can be utilized.
Regression Testing attempts to verify:
- That the application works as specified even after the changes/additions/modification were made to it.
- The original functionality continues to work as specified even after changes/additions/modifications to the software application.
- The changes/additions/modification to the software application has not introduced any new bugs
When is Regression Testing necessary?
Regression Testing plays an important role in any Scenario where a change has been made to a previously tested software code. Regression Testing is hence an important aspect in various Software Methodologies where software changes enhancements occur frequently.
Any Software Development Project is invariably faced with requests for changing Design, code, features, or all of them. Some Development Methodologies embrace change.
Extreme Programming Methodology advocates applying small incremental changes to the system based on the end-user feedback. Each change implies more Regression Testing needs to be done to ensure that the System meets the Project Goals.
It is applicable if in the course of the advancement course of action some alterations in source code are built. But if we have to have distinct operations to work thoroughly, the operation may possibly not function following specific adjustments.
So regression tests make it possible for experts to locate out anytime needed performance functions appropriately and as properly as it made use of to.
Why is Regression Testing important?
Any Software change can cause existing functionality to break. Changes to a Software component could impact dependent Components. It is commonly observed that a Software fix could cause other bugs. All this affects the quality and reliability of the system. Hence Regression Testing, since it aims to verify all this, is very important.
Making Regression Testing Cost-Effective:
Every time a change occurs one or more of the following scenarios may occur:
- More Functionality may be added to the system.
- More complexity may be added to the system.
- New bugs may be introduced.
- New vulnerabilities may be introduced in the system.
The system may tend to become more and more fragile with each change. After the change, the new functionality may have to be tested along with all the original functionality.
With each change, Regression Testing could become more and more costly.
To make the Regression Testing Cost Effective and yet ensure good coverage one or more of the following techniques may be applied:
- Test Automation: If the Test cases are automated the test cases may be executed using scripts after each change is introduced in the system. The execution of test cases in this way helps eliminate oversight, human errors. It may also result in faster and cheaper execution of Test cases. However, there is a cost involved in building the scripts.
- Selective Testing: Some Teams choose to execute the test cases selectively. They do not execute all the Test Cases during the Regression Testing. They test only what they decide is relevant. This helps reduce Testing Time and Effort.
Regression Testing? What to Test?
Since Regression Testing tends to verify the software application after a change has been made everything that may be impacted by the change should be tested during Regression Testing. Generally, the following areas are covered during Regression Testing:
– Any functionality that was addressed by the change
– Original Functionality of the system
– Performance of the System after the change was introduced
What Scenarios Should Be Checked with Regression Tests?
- The practical factors which are seen for the conclusion-buyers.
- Just about every complicated test scenario.
- Scripts that detect repeated difficulties.
- Boundary price exams.
- One effective and just one failure scenario as samples.
- Just about every integration script.
- Cases that include the main characteristics of the products undertake a look at.
If the technique features are continuously alterations and new purposeful are often included, then to perform regression tests is fairly highly-priced. The way out is the check instruments that assist to simplify the examining procedure and lower its price.
What Are the Resources for Regression Testing?
- UFT-. It is intended to compose automatic regression, as nicely as useful situations. For automation, VBScript language is utilized. This resource is key phrase-based and info-driven.
- Selenium – an open-supply device for automated screening of internet apps. Browser-based regression testing can be executed with the use of Selenium.
- RFT (Rational Practical Tester) – Java tool designed by IBM. It is used to automated regression tests. Besides that, the resource can be integrated with Rational Test Manager.
Regression Testing? How to Test?
Like any other Testing Regression Testing Needs proper planning. For an Effective Regression Testing to be done the following ingredients are necessary:
- Create a Regression Test Plan: Test Plan identified Focus Areas, Strategy, Test Entry, and Exit Criteria.
It can also outline Testing Prerequisites, Responsibilities, etc.
- Create Test Cases: Test Cases that cover all the necessary areas are important. They describe what to Test, Steps needed to test, Inputs, and Expected Outputs. Test Cases used for Regression Testing should specifically cover the functionality addressed by the change and all components affected by the change.
- The Regression Test case may also include the testing of the performance of the components and the application after the change(s) were done.
- Defect Tracking: As in all other Testing Levels and Types, It is important Defects are tracked systematically, otherwise, it undermines the Testing Effort.
What Are the Regression Testing Methods?
- Retest all
- Check assortment
- Prioritization of exam situations
The system of retesting all designed examination instances in the suite fairly prices tag-intense and time-consuming as it calls for substantially hard work and means. If the deadline is coming, then this technique will not produce.
But alternatively of reusing the whole suite, it is improved to make use of only the specified assessments which can be divided into obsolete and reusable exam cases. The specialists will be shell out attention and rerun only reusable tests.
The most resultative technique is the choice of check circumstances dependent on their priority. In such a problem, the specialists reuse only those scripts that are important in accordance with enterprise purposes, primary functions, and so forth. As an end result, tests require significantly less time and sources.