Function contains

tutorials/external/catch.hpp:11392–11394

        return !s.empty() && s[s.size()-1] == suffix;
    }
    bool contains( std::string const& s, std::string const& infix ) {
        return s.find( infix ) != std::string::npos;
    }
    void toLowerInPlace( std::string& s ) {
        std::transform( s.begin(), s.end(), s.begin(), toLowerCh );
    }