Method operator <=

unittests/catch.hpp:1407–1409

        }
        template<typename RhsT>
        auto operator <= ( RhsT const& rhs ) -> BinaryExpr<LhsT, RhsT const&> const {
            return { static_cast<bool>(m_lhs <= rhs), m_lhs, "<=", rhs };
        }

        auto makeUnaryExpr() const -> UnaryExpr<LhsT> {
            return UnaryExpr<LhsT>{ m_lhs };