https://twitter.com/2btc10000pizzas/status/1303768424133398528

No idea what could be going on here :/
using ActionList = Action[MAX_ACTIONS];
    
    template <typename Fn>
    void ForEachMergeSetup(Fn&& fn)
    {
        ActionList arg_actions = {};
        ForEachNoDup(arg_actions, ENABLE_TEST, NEGATE_REG, [&] {
            ActionList conf_actions = {};
            ForEachNoDup(conf_actions, ENABLE_TEST, NEGATE_REG, [&] { fn(arg_actions, conf_actions); });
        });
    }
};
BOOST_FIXTURE_TEST_CASE(util_ChainMerge, ChainMergeTestingSetup)
{
    CHash256 out_sha;
    FILE* out_file = nullptr;
    if (const char* out_path = getenv("CHAIN_MERGE_TEST_OUT")) {
        out_file = fsbridge::fopen(out_path, "w");
        if (!out_file) throw std::system_error(errno, std::generic_category(), "fopen failed");
    }
    ForEachMergeSetup([&](const ActionList& arg_actions, const ActionList& conf_actions) {
        TestArgsManager parser;
        LOCK(parser.cs_args);
        parser.AddArg("-regtest", "regtest", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
        parser.AddArg("-testnet", "testnet", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
        auto arg = [](Action action) { return action == ENABLE_TEST  ? "-testnet=1"   :
                                              action == DISABLE_TEST ? "-testnet=0"   :