Function startsWith

unittests/catch.hpp:9573–9575

namespace Catch {

    bool startsWith( std::string const& s, std::string const& prefix ) {
        return s.size() >= prefix.size() && std::equal(prefix.begin(), prefix.end(), s.begin());
    }
    bool startsWith( std::string const& s, char prefix ) {
        return !s.empty() && s[0] == prefix;
    }