Class CopyableStream

tests/catch.h:1207–1218

    struct STATIC_ASSERT_Expression_Too_Complex_Please_Rewrite_As_Binary_Comparison;

    struct CopyableStream {
        CopyableStream() {}
        CopyableStream( CopyableStream const& other ) {
            oss << other.oss.str();
        }
        CopyableStream& operator=( CopyableStream const& other ) {
            oss.str("");
            oss << other.oss.str();
            return *this;
        }
        std::ostringstream oss;
    };

    class ResultBuilder {
    public: