Function test_map_reverse_iterators

tests/test_container_helpers.h:815–837

// Verifies: rbegin/rend work correctly
template<template<typename, typename> class MapTemplate>
void test_map_reverse_iterators() {
    using MapContainer = MapTemplate<int, fl::shared_ptr<int>>;

    MapContainer source;
    populate_map(source, 1, make_shared_int(10));
    populate_map(source, 2, make_shared_int(20));
    populate_map(source, 3, make_shared_int(30));

    // Test reverse iterators exist
    FL_CHECK(source.rbegin() != source.rend());

    // Count reverse iteration
    int count = 0;
    for (auto rit = source.rbegin(); rit != source.rend(); ++rit) {
        count++;
    }
    FL_CHECK(count == 3);

    // Move and verify
    MapContainer destination = fl::move(source);
    FL_CHECK(source.rbegin() == source.rend());  // Empty
    FL_CHECK(destination.rbegin() != destination.rend());
}

// Test iterator arithmetic for RandomAccessIterator maps (like flat_map)
// Verifies: operator+, operator-, distance calculations