Types of Regression Testing in Software Testing

Regression Testing :
Regression testing is done to ensure that enhancements or defect fixes made to the software work properly and do not affect the existing functionality. It is generally done during the maintenance phase of SDLC. Regression Testing is the process of testing the modified parts of the code and the parts that might get affected due to the modifications to ensure that no new errors have been introduced in the software after the modifications have been made. Regression testing is a kind of testing method that can be used at all three levels of testing.

Types of Regression Testing :
There are 4 types of regression testing in software testing. Let’s discuss them one by one:

1. Corrective Regression testing –
This type of testing is used in the software testing process when specifications are not modified and all test cases can be reused in the testing. It requires less time to find the faults or bugs. It is known as one of the most popular types in the current generation and also for its convenience and repetitive use in testing. 
This testing technique analyses the effect of new code on the product’s existing source code and also uses a subset of existing test cases to minimize the costs and efforts needed for testing.
 

2. Progressive Regression testing –
This type of testing is used in the software testing process when the specifications are modified or changed and all the new test cases must be created newly. This testing is recommended when you are developing new test cases. 
It also allows the testers to perform the required step within the modified or updated version of the program without using the current program code. The testing also works fine when there are only a few changes to be performed in the model and also while creating new test cases. 
 

3. Retest-all Regression testing –
This type of testing is used in the software testing process and it reuses all tests but this method of testing may require more time and cost as it does the unnecessary execution of tests. Therefore, it is advised for the testers to know and understand the activity before starting the testing process. 
However, when the modification to a system is small, this method of testing is not recommended. Also, It is not recommended to perform this testing for every software product because of time constraints as most of the clients prefer avoiding this.
 

4. Selective Regression testing –
This type of testing is used in the software testing process that uses a subset of the existing test cases to reduce the time and cost of the testing. The objective of this testing is to find the dependencies between a test case and the program entities it covers. Selective regression uses the following steps in its testing process:

• Step 1. The first step is to identify the affected components of the software after the program has been changed.
   
• Step 2. After that, it selects a subset of test cases from an existing test suite(set of test cases) that covers the components of software affected by the changes or modifications.
   
• Step 3. Then, it tests the changed program to create the correctness of the program. 
   
• Step 4. After that, it examines the test results to identify the software failure.
   
• Step 5. If it finds any fault then it corrects that fault(s) that causes that failure.
   
• Step 6. At last, it updates the test suite and test history of the program.

Various types of testing are used by software engineers and testers. Therefore, every tester needs to find the right testing type and set of processes so that they can save cost and energy and work with great efficiency.