Method EnvGuard

unit_tests/storage/shared_memory.cpp:16–22

    bool was_set;

    EnvGuard(const std::string &name_) : name(name_)
    {
        const char *val = std::getenv(name.c_str());
        was_set = (val != nullptr);
        if (was_set)
            saved_value = val;
    }

    ~EnvGuard()
    {