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.
#define BOOST_TEST_MAIN
#include <boost/test/unit_test.hpp>
BOOST_AUTO_TEST_CASE( test ) { BOOST_FAIL( "Test is not ready yet" ); }
Running 1 test case...
test.cpp(6): fatal error in "test": Test is not ready yet
*** 1 failure
detected in test suite "Master Test Suite"