If you just want to do the Gilded Rose refactoring in C++ and would like a Combination Approvals test to lean on. Use this with the 'cpp_catch2' version.

gildedrose_catch.cpp

#include <catch2/catch.hpp>
#include "ApprovalTests.hpp"

#include "GildedRose.h"

std::ostream &operator<<(std::ostream &os, const Item &obj) {
    return os
    << "name: " << obj.name
    << ", sellIn: " << obj.sellIn
    << ", quality: " << obj.quality;
}


static Item updateItem(string name, int sellIn, int quality);

TEST_CASE("UpdateQuality")
{
    vector<string> names = {"foo", "Aged Brie", "Backstage passes to a TAFKAL80ETC concert", "Sulfuras, Hand of Ragnaros"};
    vector<int> sellIns = {-1, 0, 5, 6, 10, 11};
    vector<int> qualitys = {0, 1, 2, 49, 50};

    ApprovalTests::CombinationApprovals::verifyAllCombinations(
            updateItem,
            names,
            sellIns,
            qualitys
            );
}

static Item updateItem(string name, int sellIn, int quality) {
    vector<Item> items;
    items.push_back(Item(name, sellIn, quality));
    GildedRose app(items);
    app.updateQuality();
    auto item = app.items[0];
    return item;
}