What is Unit test, Integration Test, Smoke test, Regre...

Unit tests, integration tests, smoke tests, and regression tests are all types of software testing methodologies used to ensure that software applications function correctly and meet specified requirements. Each type of test serves a different purpose and is used at different stages of the software development lifecycle.

Unit Testing

Unit testing involves testing the smallest testable parts of an application, called units, individually and independently to ensure that they perform as expected[16]. This type of testing is typically performed by developers as they work on the code, and it is often automated. Unit tests are designed to be quick to write and execute, and they help to catch bugs at an early stage.

Integration Testing

Integration testing focuses on combining individual units of an application and testing them as a group to ensure that they function together correctly[4]. This type of testing is crucial because it helps to identify issues that may not be apparent during unit testing, such as problems with the interfaces between different components of the software.

Smoke Testing

Smoke testing, also known as "Build Verification Testing" or "Confidence Testing," is a preliminary test to check the basic functionality of a software application[1][2][5][6][8][10][11]. It is typically conducted to ensure that the most critical functions of the software work and that there are no major showstoppers before moving on to more rigorous testing. Smoke testing can be manual or automated and is usually performed after a new software build is received.

Regression Testing

Regression testing is a type of software testing that verifies that previously developed and tested software still performs correctly after it has been changed or interfaced with other software[7][9][12][13][14][15]. This testing is crucial for catching bugs that could be introduced by changes in the code, ensuring that new code does not adversely affect existing functionality.

Differences Between the Tests

• Scope and Focus: Unit testing is focused on individual components, integration testing on the interaction between components, smoke testing on basic functionality, and regression testing on ensuring that existing functionality remains unaffe...