Register subclasses with OmniAuth.strategies

[md5]

This PR updates OmniAuth::Strategies::SAML to register any subclasses as strategies with OmniAuth. This parallels what's done in the omniauth-oauth2 gem (cf. here).

[suprnova32]

instead of declaring the subclass in a let can we just initialize it within the it block?

it 'registers subclasses in OmniAuth.strategies' do
  subclass = Class.new(described_class) # or described_class.new
  expect(OmniAuth.strategies).to include(subclass)
end

I find this approach easier to read as it defines everything the test needs within the test itself.

[md5]

Updated and amended. I also threw described_class into the include check since omniauth-oauth2 is doing that check and it seems reasonable.

[coveralls]

Coverage increased (+0.08%) to 96.8% when pulling ec6f041 on appropriate:register-subclasses into 7175717 on omniauth:master.

[md5]

These jruby-head and ruby-head Travis failures are annoying...

[coveralls]

Coverage increased (+0.07%) to 96.787% when pulling 1894d39 on appropriate:register-subclasses into 7175717 on omniauth:master.

[suprnova32]

@md5 I agree. We should move them back to the allowed_failures.

[md5]

@supernova32 Updated in f74d983 to allow failures of jruby-head and ruby-head.

[coveralls]

Coverage increased (+0.07%) to 96.787% when pulling f74d983 on appropriate:register-subclasses into 7175717 on omniauth:master.