I believe that the original definition, way back before most of us were born, was a test of the smallest possible unit, i.e a single function ect. At least according to Wikipedia, in 1969, it was defined at unit tests, component tests and integration tests.
In todays development world, the unittest is primarily a developer tool to help speed up development. One should not be afraid to delete unittests if they are doing refactorings. But the long term value is always in the integration tests.
In todays development world, the unittest is primarily a developer tool to help speed up development. One should not be afraid to delete unittests if they are doing refactorings. But the long term value is always in the integration tests.