How to unit test code that makes HTTP requests with twisted.web.client.Agent?
twisted
Solution
it is certainly possible to use a real `Agent`. You must construct the `Agent` instance with a reactor as first argument; as such, you can provide a fake reactor, such as `MemoryReactor`. Although that's a pretty handy way to get down in the guts of what `Agent` is doing, it's really mostly useful for testing `Agent` itself. Injecting a fake `Agent` is many times an easier route, because its api is both shallow (almost everything passes through `Agent.request` and simple (it returns an `IResponse`)
Problem
I'm looking for hints or examples that illustrate how to unit test code that makes HTTP requests using twisted.web.client.Agent. Is it possible to use the real Agent in tests and configure it to connect to a fake HTTP server using StringTransport (no real TCP connetion)? Or is it better to mock out the Agent and inject a mock into classes that use the Agent?