Mike Cohn's Test Pyramid explains the different types of automated tests needed for software development. The test pyramid is basically used to maximize automation at all levels of testing, including unit testing, service level testing, UI testing, etc. The pyramid also states that unit tests are faster and more isolated, while UI tests, which are at the top, are more time-consuming and are centered around integration.
In accordance with the pyramid, the number of tests should be highest at the first layer. At the service layer, fewer tests should be performed than at the unit test level, but greater than that at the end-to-end level.
