The test_observer class encapsulates observers of test execution. It provides a simple null style observer behavior.

namespace boost { namespace unit_test {

class BOOST_TEST_DECL test_observer {
public:
    // test observer interface
    virtual void    test_start( counter_t /* test_cases_amount */ ) {}
    virtual void    test_finish() {}
    virtual void    test_aborted() {}

    virtual void    test_unit_start( test_unit const& ) {}
    virtual void    test_unit_finish( test_unit const&, unsigned long /* elapsed */ ) {}
    virtual void    test_unit_skipped( test_unit const& ) {}
    virtual void    test_unit_aborted( test_unit const& ) {}

    virtual void    assertion_result( bool /* passed */ ) {}
    virtual void    exception_caught( execution_exception const& ) {}

    virtual int     priority() { return 0; }
};

} }