Is Nameko service code incompatible with the Hypothesis testing library?

[tom....@sohonet.com]

Hi,

Hypothesis is a property based testing library. I tried to test Nameko service code with it, but had problems due to the fact it edits global state (random.seed(0)), while nameko does setup with eventlet.

I've asked this question on hypothesis-users:

https://groups.google.com/forum/#!topic/hypothesis-users/j2z7nlSz-wo

If anyone has used Hypothesis to test Nameko service code, I'd love to hear how you got on.

Thanks,

Tom

[Matt Yule-Bennett]

I've not used Hypothesis, but looking at your question on hypothesis-users, I think there are a few things you can try:

1. Does your service under test actually use RabbitMQ? If not, removing the `rabbit_config` will stop Nameko trying to set up the vhosts.

2. From your comment at the end, I guess you're most interested in testing the paths through the service method, rather then the entrypoints/dependency providers? If so, you might find the `worker_factory` a useful helper. It gives you a service instance, so you can invoke service methods on it as regular methods on an object. If you did this you wouldn't need RabbitMQ to be running even if your service has AMQP extensions.

3. From what I understand, the problem is that Hypothesis is setting the random number generation at the process level, while another thread is in the process of using it . This is surely a general problem for any program that uses threads (green or otherwise), but there are probably a couple ways you can work around it:

a) Update the vhost_pipeline (by overriding or patching) to use something other than random.choice to generate the random names.

b) Make sure Hypothesis sets random.seed(0) before the vhost pipeline thread starts running.

Hope that helps,

Matt.