What are the various Testing Levels?a.Unit Testingb.System Testingc.Integration Testingd.All

The various levels of testing in software development are:

a. Unit Testing: This is the first level of testing and is often performed by developers themselves. Unit testing is focused on checking a small piece of work to ensure its correctness. In object-oriented programming, a unit could be an entire interface, such as a class, but could also be an individual method.

b. Integration Testing: Integration testing is the phase in software testing in which individual software modules are combined and tested as a group. It occurs after unit testing and before system testing. Integration testing takes as its input modules that have been unit tested, groups them in larger aggregates, applies tests defined in an integration test plan to those aggregates, and delivers as its output the integrated system ready for system testing.

c. System Testing: System testing is a level of testing that validates the complete and fully integrated software product. The purpose of a system test is to evaluate the system’s compliance with the specified requirements.

d. All: This option implies that all the above-mentioned testing levels are part of the software testing process. Each level has its own purpose and helps improve the quality of the product.