Cannot mock 5xx responses

[feld]

If I try to mock a 5xx response it blows up the entire test. I'm using the Bandit adapter.

e.g.,

    TestServer.add("/some/path",
      via: :get,
      to: fn conn ->
        Plug.Conn.send_resp(conn, 500, "")
      end
    )

14:20:45.892 [error] retry: got response with status 500, will retry in 1000ms, 3 attempts left
warning: ** (RuntimeError) TestServer.Instance #PID<0.628.0> received an unexpected GET request at /some/path.


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[feld]

I started digging deeper and found the error message is actually from Req.

I'm in the process of attempting to switch a project away from Tesla/Tesla.Mock to Req/TestServer

[feld]

I have the solution. If your code expects to be able to do intelligent handling of 408/429/5xx responses you must pass retry: false to Req or else this kind of scenario surfaces and you will not be able to validate it in your tests.

Req is batteries included, but this is more than I expected 🥲

Sorry for the noise, hopefully someone else finds this useful.

[danschultzer]

Yeah, by default req will retry four times, so either you'll have to add four expectations (could be a small helper function you wrap around TestServer.add/2), or add retry: false as you did (though that setting should only exist for test env). I think the latter is much better choice because otherwise the test becomes super slow with the throttle that req has on retries.