Acceptance Testing (AT) can be translated as acceptance test. It is the final test before delivery of a device or system to the customer. Such acceptance tests can be performed according to a specification and include both the hardware and the software.
Acceptance tests are generally performed as so-called black-box tests. In these tests, the tester applies the specified characteristic values to the input of the system and compares the resulting output values with the results specified in the requirements specification or otherwise, without any knowledge of the system and its operation.
If the acceptance test is performed by the person who also uses the system, it is called User Acceptance Testing (UAT). If such a system is developed and installed by an external supplier, it is called Customer Acceptance Testing (CAT). Both AT tests refer to the fact that the system can be used.
There is another acceptance test, Factory Acceptance Testing (FAT), which is used to test the electronic components and is performed at an earlier stage of production.