Stubbing an invalid record for inherited_resources
Posted on January 15, 2014 by Carsten Zimmermann
Saving a record in a controller has at least two outcomes: it can succeed or it can fail and you want to test this branching.
In order to decouple a functional test from the concrete attributes or other states that define its validity, it’s good to skip the actual validation and stub it out instead.
Stubbing a failing record for a create or update request is fairly easy for a vanilla controller:
describe MyController do
describe 'POST create' do
it 'creates a record' do
allow_any_instance_of(MyModel).to receive(:valid?).and_return(true)
expect { post :create }.to change { MyModel.count }
end
it 'fails to create a record' do
allow_any_instance_of(MyModel).to receive(:valid?).and_return(false)
expect { post :create }.not_to change { MyModel.count }
end
end
endHowever, it isn’t that easy with inherited_recources.
(or more accurately with responders which is used
behind the scenes). Inherited Resources considers a record invalid when it has errors (see also
this issue).
Here is an approach to properly stub record validity for use with Inherited Resources:
# spec/support/advanced_validity_stubbing.rb
module AdvancedValidityStubbing
def stub_validity(klass, validity)
allow_any_instance_of(klass).to receive(:valid?).and_return(validity)
unless validity
errors = klass.new.errors
errors.add(:base, 'Stubbed to be bad')
allow_any_instance_of(klass).to receive(:errors).and_return(errors)
end
end
end
# spec/spec_helper.rb
RSpec.configure do |config|
# ...
config.include AdvancedValidityStubbing
endThe modified controller spec may look like this:
describe MyController do
describe 'POST create' do
it 'creates a record' do
stub_validity MyModel, true
expect { post :create }.to change { MyModel.count }
end
it 'fails to create a record' do
stub_validity MyModel, false
expect { post :create }.not_to change { MyModel.count }
end
end
end