Method WithinRelMatcher

extras/tests/catch/catch.hpp:11640–11645

    }

    WithinRelMatcher::WithinRelMatcher(double target, double epsilon):
        m_target(target),
        m_epsilon(epsilon){
        CATCH_ENFORCE(m_epsilon >= 0., "Relative comparison with epsilon <  0 does not make sense.");
        CATCH_ENFORCE(m_epsilon  < 1., "Relative comparison with epsilon >= 1 does not make sense.");
    }

    bool WithinRelMatcher::match(double const& matchee) const {
        const auto relMargin = m_epsilon * (std::max)(std::fabs(matchee), std::fabs(m_target));