Functional testing

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In software development, functional testing is a form of software system testing that verifies whether a system meets its functional requirements.^[1][2]

Generally, functional testing is black-box, meaning the internal program structure is ignored (unlike for white-box testing).^[3]

Sometimes, functional testing is a quality assurance (QA) process.^[4]

Functional testing differs from acceptance testing. Functional testing verifies a program by checking it against design documentation or specification^{[citation needed]}, while acceptance testing validates a program by checking it against the published user or system requirements.^[3]

As a form of system testing, functional testing tests slices of functionality of the whole system. Despite similar naming, functional testing is not testing the code of a single function.

The concept of incorporating testing earlier in the delivery cycle is not restricted to functional testing.^[5]

In fixture testing, while ICT fixtures test each individual component on a PCB, functional test fixtures assess the entire board's functionality by applying power and verifying that the system operates correctly.^[6]