semiregular_test.cc

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#include "catch.hpp"
#include "semiregular.hh"
#include <memory>
 
 
// Mockup for an transform-iterator containing a transformation function (e.g.
// a lambda).
template<typename Op> struct Iter {
        Iter() = default;
        explicit Iter(Op op_) : op(std::move(op_)) {}
        semiregular_t<Op> op; // wrap 'Op' in semiregular_t<T>
};
 
TEST_CASE("semiregular")
{
        // This doesn't CHECK() anything, it only tests that the code compiles.
        SECTION("semiregular_t<lambda>") {
                int g = 42;
 
                // create dummy lambda, captures 'g' by-reference.
                auto lambda = [&](int i) { return i + g; };
                auto l2 = lambda; (void)l2; // lambda is copy-constructible
                // l2 = lambda; // ok, doesn't compile: lambda is not copy-assignable
                // decltype(lambda) l3; // ok, doesn't compile: not default-constructible
 
                // create iterator containing this lambda
                auto iter1 = Iter(std::move(lambda));
                auto iter2 = iter1; // ok, copy-constructible
                iter2 = iter1; // ok, copy-assignable
                decltype(iter1) iter3; // ok, default-constructible
                (void)iter2; (void)iter3;
        }
        SECTION("semiregular_t<unique_ptr<int>>") {
                // unique_ptr
                using T = std::unique_ptr<int>;
                auto t1 = std::make_unique<int>(43);
                // T t2 = t1; // ok, doesn't compile: move-only
 
                // wrapped in semiregular_t<T>
                using ST = semiregular_t<T>;
                ST st1 = std::move(t1);
                // ST st2 = st1; ok, doesn't compile because move-only
                ST st2 = std::move(st1);
                st1 = std::move(st2);
        }
}