final expect_exception

finalExpect

template<typename ExecLambda, typename OnThrowLambda, typename NoThrowLambda>
auto expect_exception( ExecLambda exec_lambda, bool expect_to_throw,
                       OnThrowLambda throw_lambda, NoThrowLambda no_throw_lambda,
                       decltype(throw_lambda()) expected_return_value)
{
    bool threw;
    decltype( exec_lambda() ) x;
    
    try {
        x = exec_lambda();
        threw = false;
    }
    catch (...) {
        threw = true;
    }

    if ( expect_to_throw != threw ) {
        if (expect_to_throw)
            throw "failed to catch expected exception";
        else
            throw "caught unexpect exception";
    } else {
        if (expect_to_throw) {
            return throw_lambda();
        } else {
            auto rval = no_throw_lambda(x);
            if ( rval != expected_return_value )
                throw "Unexpected Return Value!!!";
            else
                return rval;
        }
    }
}


template<typename ExecLambda, typename ExpectThrowLambda,
         typename OnThrowLambda, typename NoThrowLambda>
auto expect_exception_l( ExecLambda exec_lambda,
                         ExpectThrowLambda expect_throw,
                         OnThrowLambda throw_lambda,
                         NoThrowLambda no_throw_lambda,
                         decltype(throw_lambda()) expect)
{
    return expect_exception(exec_lambda, expect_throw(),
                            throw_lambda, no_throw_lambda, expect);
}