# Unit Tests¶

## Unit Test Files¶

Unit test files are located in the “Tests/Unit/” folder of the according extension, within a sub-structure matching the structure in the Classes/ folder.

As naming convention, Test is appended at the end of the name. As example, the unit test class file for typo3/sysext/core/Classes/Database/PreparedStatement.php located at typo3/sysext/core/Tests/Unit/Database/PreparedStatementTest.php.

## Using Unit Tests¶

Although the coverage is far from complete, there are already quite a lot of unit tests for the TYPO3 Core. Anytime something is changed in the Core, all existing unit tests are run to ensure that nothing is broken.

Unit tests should be as concise as possible. Since the setUp() and tearDown() methods always have the same responsibility, these methods do not need a documentation block.
Since unit tests never return anything, they do not need an @return tag.