Unit testing is a method by which individual units of source code are tested to determine if they are fit for use.
Ideally, each test case is independent from the others: substitutes like method stubs, mock objects, fakes and test harnesses can be used to assist testing a module in isolation. Unit tests are typically written and run by software developers to ensure that code meets its design and behaves as intended.Wikipedia
is a method of software testing that examines the functionality of an application without peering into its internal structures or workings
is a method of software testing that tests internal structures or workings of an application, as opposed to its functionality
- Unit testing is closely related to Test Driven Development.