...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Declares and registers a fixture used by all test cases under a test suite. Each test case in the subtree of the test suite uses the fixture. The class implementing the fixture should have the appropriate interface. As any fixture, it is possible to have test assertions in the fixture class.
See here for more details.