What Lays The Differentiation Between Regression Testing And Functional Testing?

April 19, 2020

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Functional testing is defined as a process of testing the features and operational behavior of a product in order to determine that the products correspond to the specifications of the product. This type of testing adheres to the output generated in response to the selected inputs. On the contrary, Regression testing is process of rechecking the newly deployed code in order to determine the impact of changes made to the code or operation. It is done to ensure that a small addition or tweak in the program hasn't broken down the existing functionality.

Difference in the Regression Testing and Functional Testing

1. Purpose

   The purpose of Regression testing is to clearly reassure whether the updated code had adverse effects on the newly updated code or existing features whereas in the functional type of testing or black box testing, a functionality or code undergoes a microscopic examination in order to maintain a standard quality.

2. Usability

   The regression testing is used to test an already developed end product is tested on a repeated basis restricting to a certain area that was updated whereas in the latter's case the testing is done on the individual functionalities or modules as a whole.

3. Requirement

   The Regression testing is required only in certain conditions when:

   • The requirement of code is manipulated.
   • Addition of a new feature to existing functionality.
   • Mending defects.
   • Repairing the issues.

   An operation undergoes functionality testing only when:

   • A system is described.
   • The working of a system as a whole is to be examined.
   • Verifying a program against its specifications.
   • Determining the working of a system and its functions.
4. Techniques

   The techniques used in Functional testing are specific and are as follows:

   • Black Box testing
   • White Box testing
   • Unit testing
   • Integrating testing
   • UA testing
   • Interface testing
   • System testing

   In Regression testing type, the researchers have reported several types of techniques. These are as follows:

   • Procedural
   • Object-oriented
   • Component-based
   • Database
   • Aspect
   • Web applications






5. Process

   The functional testing sticks to strict process that firstly the project requirements are understood by the tester. Next, the inputs of the data are identified. Post the identification of input values, they are computed against the expected or resulting outcomes. It is compared with the selected input values. The test is concluded after the actual result is matched with the expected outcomes. Any discrepancy found, will lead to occurrence of a bug or defect.

   • Detection of Function
   • Creation of input data
   • Seeking out the end result
   • Implementation of test case
   • Creating a comparison between the input and output
   • Verifying the working of application

   On the contrary, the process of Regression testing type is entirely different as this activity takes place only when a program is modified. In this context, the selection of a relevant of test cases from the initial test is done. It is done in the later stages when the build is ready to go live.

   The activities involved in this type of testing are as follows:

   • Identification of modified parts
   • Selection of test cases
6. Types of test cases

   The types of Functional test cases are:

   • Sanity testing
   • Usability testing
   • Smoke testing

   The types of Regression case are:

   • Redundant test cases
   • Fault-revealing test cases
   • Modification-revealing test cases
   • Modification-traversing test cases

Both these types of testing are entirely differentiate from one another in all aspects. Also, the testers need to perform such test at different stages of the project. The comparison between the two is futile as the two of these testing are entirely different from each other.