3 ms·

Because a kernel is not a user-land?

• zibzab 5y ago
  I agree with parent that unit testing privileged bare metal code is not always possible, at least not without spending 10x-100x dev time on writing tests. Example: anything that directly accesses MMU or caches.
  • rurban 5y ago
    On the contrary, simulating MMU or caches are trivial. You can create a memory subsystem mock in a few hours. IO, assembly and interrupts are much harder.
    • zibzab 5y ago
      How would you create a mock object for something that modifies the memory layout of the unit test while it is running?
      • Dylan16807 5y ago
        > How would you create a mock object for something that modifies the memory layout of the unit test while it is running? There's two ways I can interpret "the unit test". 1) "How would you create a mock object for modifying the memory layout of the code being tested?" That's just a routine that shuffles around some bytes. Or marks parts of the address space to fault so it can simulate the contents. 2) "How would you create a mock object for modifying the memory layout of the code performing the test?" That wouldn't be a test. The code performing the test isn't inside its own simulation.
      • rurban 5y ago
        You create your mmap's on init. The MMU is just a simple 3way array lookup, as a Unicode table.
        • yencabulator 5y ago
          Unicode?