Betamax objects share global configuration

[jerith]

All configuration information seems to be shared between all Betamax objects, which means that creating a new instance changes the behaviour of existing objects:

>>> from betamax import Betamax
>>> from requests import Session
>>> bm = Betamax(Session(), cassette_library_dir="1", default_cassette_options={"record_mode": "none"})
>>> print bm.config.cassette_library_dir, bm.config.default_cassette_options["record_mode"]
1 none
>>> bm2 = Betamax(Session(), cassette_library_dir="2", default_cassette_options={"record_mode": "all"})
>>> print bm2.config.cassette_library_dir, bm2.config.default_cassette_options["record_mode"]
2 all
>>> print bm.config.cassette_library_dir, bm.config.default_cassette_options["record_mode"]
2 all

This is both surprising and problematic when one wants to use different recorders for different requests within the same test.

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[sigmavirus24]

It shouldn't be that surprising given that we explicitly mention that the Configuration object is a proxy to global settings and is meant to be used once. The documentation for the Betamax object is currently out of date (in suggesting you should pass default_cassette_options). Further, one goal of this library was to be as similar to the original VCR as possible which is why we encourage the practice of calling Betamax.configure() before your tests to configure the library.

I can see the purpose of setting different cassette library directories, so I'll fix that, but I'm also going to deprecate passing a dictionary of default cassette options as well. It doesn't quite belong there. All of those options should either be set once globally, or if they are a per-request issue, should be passed to Betamax#use_cassette. You can, and should be doing this:

bm = Betamax(Session())  # cassette_library_dir optional
bm2 = Betamax(Session())
bm.use_cassette('cassette_name', record='none')
bm.use_cassette('other_cassette_name', record='all')

Granted the documentation for this is also missing.

[jerith]

Awesome, thanks for the quick response!

Would it be reasonable to use named parameters instead of **kwargs in Betamax#use_cassette so it's easier to see what's available?

[sigmavirus24]

Would it be reasonable to use named parameters instead of **kwargs in Betamax#use_cassette so it's easier to see what's available?

Oh damn, I never responded. I'm totally okay with that. I was using **kwargs because it was easy.

[sigmavirus24]

FWIW, I'm considering a 1.0 in which each betamax.Betamax instance gets a Configuration object that, once set-up, is immutable.