Add some kind of setup/cleanup for temporary files for testing, to be called at the start/end of a test function

[Ttibsi]

Spitballing - we don't just want a mk_temp_file() and cleanup_temp_file() function if we can help it.. some kind of struct that handles this in the constructor/destructor to use RAII for cleanup. Something like this (untested)

struct TempFile {
    explicit TempFile(std::string fileName, std::string contents) {
        // make the file here        
        // Contents could be empty as well (second ctor?)
    }

    // cleanup
    ~TempFile() {}

    // Other methods
    bool compare_file(); // does the temp file match expected content
};