Production Assembly Tests (PAT):

These tests are performed on each product in-line or at the end-of-line to ensure that the assembly process is maintained. These tests are not used to verify that various hardware or software components are working; only the bare minimum of testing is needed to ensure a correct assembly process.

There may also be some regulatory testing, depending on the type of product, that must be done periodically as long as a product is in production. These Regulatory Agency Standard Tests are defined here.

Field Service Tests (FST):

These tests are high-level tests - easy and quick to perform by non-engineers, such as the User or a field service person. These are GO/NO-GO tests that allow quick determination of whether a product is working or needs to be sent to a repair facility for service or replacement.

Factory Debug Tests (FDT):

These tests are mid-level tests and usually are based on a 'trouble shooting' tree and/or automated testing. They allow a service technician to quickly isolate a problem to where he can either repair an economically replaceable component or send the product to the garbage can or to re-cycling. Necessarily, these tests are simple and quick and are based on the economics of the warranty business model.

Regression/Functional Tests (RFT):

These full functional tests are used, when there are changes made to a product already in production and in the field, whether they result in a model number revision or not. These tests ensure that the changes, no matter how minor, do not adversely effect other aspects of product performance, appearance, functionality, safety, quality, reliability or serviceability. The RFT tests usually do not have the same structure as product functional tests, since the RFT will test for anomalies in lower levels of hardware and software that a user would never see.

Field Validation Tests (FVT):

These tests are sometimes called User Tests or Beta Tests. They are gauged to the Product Requirements Specification to check that the product IS exactly as it was defined to be in all aspects, claims and usefulness. This is the ultimate proof of your product claims.