The major difference between a unit test and a functional test is the scope of testing, as described in the following:

• Unit test: A unit test usually focuses on the testing of individual components in a software that could be factored to a single function or a method of a class
• Functional test: Functional tests are also known as integration tests and usually test a specific functionality of the system that may encompass the interaction of multiple components with each other, along with their interaction with the external environment, such as database systems.