Integration tests ensure that the components of an application is running properly at a level that includes the auxiliary infrastructure of the application, such as the voice user interface, the backend, and the integration with external systems.
Integration tests evaluate the components of an application at a higher level than unit tests. Unit tests are used to test isolated software components, such as individual class methods. Integration tests check that two or more components of an application work together, and they generate an expected result, possibly including all the components necessary to fully process a request.