On November 6, 2018 6:41:23 AM EST, Chris Withers <chris@simplistix.co.uk> wrote:

On 06/11/2018 05:43, Moshe Zadka wrote:

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Some of the best advice depends on details of the application. One trick that is sometimes useful is passing in a "fake" reactor object.

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This, of course, is only useful if the application is structured in a

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way that functions/classes expect to get a reactor, instead of reaching for the global one. However, usually *that's* not a complicated refactoring to do.

Cool, do you have any example tests that do this? Interesting, looks like pytest-twisted does away for the need for this by showing how to install a fake reactor globally: https://github.com/pytest-dev/pytest-twisted/blob/master/pytest_twisted.py#L...

What is 'fake' about this globally installed normally-the-default reactor? (Otherwise the qt5reactor if chosen)

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You can, of course, use a real reactor and a real client to pump data. However, in that case, you probably do want to switch to trial so that you can return a deferred from a test function and have the reactor run until the deferred fires. This is not great, but can work in a pinch.

pytest-twisted looks like it supports this pattern too, allowing test functions to return deferreds...

I use @pytest_twisted.inlineCallbacks anyways, yes. Overall I'm not clear what was recommended here. Why fake the reactor? Even if not using a 'real client' wouldn't you just fake the data going through the connections rather than faking the entire reactor? Cheers, -kyle

On November 6, 2018 6:41:23 AM EST, Chris Withers <chris@simplistix.co.uk> wrote:

On 06/11/2018 05:43, Moshe Zadka wrote:

...

Some of the best advice depends on details of the application. One trick that is sometimes useful is passing in a "fake" reactor object.

...

This, of course, is only useful if the application is structured in a

...

way that functions/classes expect to get a reactor, instead of reaching for the global one. However, usually *that's* not a complicated refactoring to do.

Cool, do you have any example tests that do this? Interesting, looks like pytest-twisted does away for the need for this by showing how to install a fake reactor globally: https://github.com/pytest-dev/pytest-twisted/blob/master/pytest_twisted.py#L...

What is 'fake' about this globally installed normally-the-default reactor? (Otherwise the qt5reactor if chosen)

...

You can, of course, use a real reactor and a real client to pump data. However, in that case, you probably do want to switch to trial so that you can return a deferred from a test function and have the reactor run until the deferred fires. This is not great, but can work in a pinch.

pytest-twisted looks like it supports this pattern too, allowing test functions to return deferreds...

I use @pytest_twisted.inlineCallbacks anyways, yes. Overall I'm not clear what was recommended here. Why fake the reactor? Even if not using a 'real client' wouldn't you just fake the data going through the connections rather than faking the entire reactor? Cheers, -kyle