heck_cxx_template/test/test_hello_world.cc

// This file is under GNU General Public License 3.0
// see LICENSE.txt
#include "hello_world.hh"
#include <iostream>

// 2 Reasons why this 'using namespace' is okay
// 1. We cannot put main() in the namespace pEp,
// 2. If we were to extract parts of this file into a header-extension (hxx) as a template function/class
// we would be in the namespace pEp anyways.
using namespace pEp;

int main()
{
    std::cout << "Test Hello World" << std::endl;
    {
        std::cout << "Test non-template func" << std::endl;
        std::string ret = HelloWorld::hello_world();
        std::cout << ret << std::endl;
        assert(ret == "hello world");
    }

    {
        std::cout << "Test invoke generated template for std::string" << std::endl;
        std::string ret = HelloWorld::hello_world("pEp");
        std::cout << ret << std::endl;
        assert(ret == "pEp");
    }

    {
        std::cout << "Test specialization for int" << std::endl;
        int ret = HelloWorld::hello_world(404);
        std::cout << ret << std::endl;
        assert(ret == 808);
    }

    {
        std::cout << "Test specialization for double" << std::endl;
        double ret = HelloWorld::hello_world(4.04);
        std::cout << ret << std::endl;
        assert(ret == 8.08);
    }
    std::cout << "All tests passed" << std::endl;
    return 0;
}