Documentation verifying inputs, predicted results, and a set of implementation conditions for a test item.

A test case is a document that explains an input, action, or event and an expected response, to verify if a feature of an application is working correctly. A test case should contain certain such as test case identifier, test case name, objective, test conditions/setup, input data requirements, steps, and usual results.

Note that the process of developing test cases can help search problems in the requirements or design of an application, since it needs completely thinking through the operation of the application. For this reason, it's useful to prepare test cases early on in the development cycle if possible.