SFML/test/TestUtilities/GraphicsUtil.cpp

// Note: No need to increase compile time by including TestUtilities/Graphics.hpp
#include <SFML/Graphics/Color.hpp>
#include <ostream>

namespace sf
{
    std::ostream& operator <<(std::ostream& os, const sf::Color& color)
    {
        os << "0x" << std::hex << color.toInteger() << std::dec
           << " (r=" << static_cast<int>(color.r)
           << ", g=" << static_cast<int>(color.g)
           << ", b=" << static_cast<int>(color.b)
           << ", a=" << static_cast<int>(color.a) << ")";

        return os;
    }
}