3 ms·

Wouldn't each of these be a test case?

• zabzonk 3y ago
  only if you have a stateful mock server with multiple mock clients attached to it. for example, when you put a sell on the server, you are basically going to be listening on a socket for multiple responses and what the responses are will depend on the buyers (which you must also mock). and don't get me started on buying, ticker conversions between different exchanges, currency, time, etc. it is too hard to mock. to mitigate this some exchanges, such as london and paris, do provide test exchanges, which are crap, and available every other fridays, or whatever. when i worked in this area, my boss used to test my code by putting a trade on the exchange and then immediatly cancelling it. this was illegal, as he wasn't a licensed trader, and the exchanges got enraged. i refused to have anything to do with it. but my point is - you cannot do meaningful unit tests on very complex systems. even integration tests can be very hard, but are worthwhile.
  • RussianCow 3y ago
    > but my point is - you cannot do meaningful unit tests on very complex systems. I think you're missing the point: unit tests should not be testing entire systems; that's the point of integration or end-to-end tests, which are different beasts entirely. You can very much write unit tests against parts of a complex system because each test should only be testing one isolated bit of functionality in the form of inputs (including local state) and outputs.