BOOST_FAIL behave the same way as BOOST_REQUIRE_MESSAGE( false, message ). This tool is used for an unconditional error message logging and the current test case aborting.
The only tool's parameter is an error message to log.
int test_main( int, char* [] ) { BOOST_FAIL( "Test is not ready yet" ); return 0; }
test.cpp(3) : fatal error in test_main: Test is not ready yet