Fixture models

Several fixture interfaces are supported by the Unit Test Framework. The choice of the interface depends mainly on the usage of the fixture.

Fixture class model

The Unit Test Framework defines the generic fixture class model as follows:

struct <fixture-name>{
  <fixture-name>();      // setup function
  ~<fixture-name>();     // teardown function
};

In other words a fixture is expected to be implemented as a class where the class constructor serves as a setup method and class destructor serves as teardown method. The Unit Test Framework opted to avoid explicit names in fixture interface for setup and teardown methods, since it is considered most natural in C++ for tasks similar to RAII and coincides with the pure C++ solution discussed above.

This model is expected from fixtures used with BOOST_FIXTURE_TEST_CASE and BOOST_FIXTURE_TEST_SUITE.

	Caution
	The above interface prevents you from reporting errors in the `teardown` procedure using an exception. It does make sense though: if somehow more than one fixture is assigned to a test unit (e.g. using `fixture` decorator), you want all `teardown` procedures to run, even if some may experience problems.

Flexible models

In addition to BOOST_FIXTURE_TEST_CASE and BOOST_FIXTURE_TEST_SUITE the Unit Test Framework allows to associate fixture with test unit using the decorator fixture. This decorator supports additional models for declaring the setup and teardown:

a fixture defined according to the fixture class model above

a fixture defined according to the extended fixture class model, which allows for the fixture constructor to takes one argument. For example:

struct Fx
{
  std::string s;
  Fx(std::string s = "") : s(s)
        { BOOST_TEST_MESSAGE("set up " << s); }
  ~Fx() { BOOST_TEST_MESSAGE("tear down " << s); }
};

a fixture defined as a pair of free functions for the setup and teardown (latter optional)

void setup() { BOOST_TEST_MESSAGE("set up"); }
void teardown() { BOOST_TEST_MESSAGE("tear down"); }

For complete example of test module which uses these models please check decorator fixture.

Boost C++ Libraries

Fixture models

Fixture class model

Flexible models