Stub().and_raise() ain't raising?

Testing RSpec
1

I have two blocks of tests: one for testing positive outcomes and one
for testing negative. After poking around, I’ve concluded that the
underlying :verify_credentials method is getting called, despite the
stub:

describe ‘electricity credentials’ do
before(:each) do
@wizard.electricity_service = MeteredService::Base.create!()
end

  it 'with valid credentials should spawn external loader' do
    @wizard.electricity_service.stub(:verify_credentials).and_return(true)
    @wizard.electricity_loader.stub(:start)
    @wizard.electricity_loader.should_receive(:start)
    @wizard.validate_setting_electricity_credentials
  end

  it 'with invalid credentials should not spawn external loader' do
    @wizard.electricity_service.stub(:verify_credentials).and_raise('no

can do’)
@wizard.electricity_loader.stub(:start)
@wizard.electricity_loader.should_not_receive(:start)
@wizard.validate_setting_electricity_credentials
end

end

Am I missing something fundamental about .stub()?

  • ff
2

On Jan 12, 2012, at 5:32 PM, Fearless F. wrote:

 it 'with valid credentials should spawn external loader' do
   @wizard.electricity_loader.should_not_receive(:start)

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What are the failed expectations? Just paste it.

Are you sure that @wizard.electricity_service is returning the same
object on each call? If a database call is being made, there’s a good
chance it is returning a different object (which has not mocks).

3

On 13 January 2012 05:18, Fearless F. [email protected] wrote:

 received: 0 times

class Wizard < ActiveRecord::Base
def electricity_service
premise.metered_services.where(:natural_resource_id =>
NaturalResource::ELECTRICITY.id)
end
end

I think your tests are telling you to refactor your code. the
premise.metered_services.where is breaking the law of demeter. This
makes it hard to stub/mock. I’d also question the naming of the Wizard
class. One thing to consider doing is running the tests with the
pretty output and reading it.

So why should Wizard#electricity_service spawn an external loader? Why
should a Wizard have an electricity service etc.

There ia a tendency when writing specs, to focus on getting the spec
to pass, and doing complicated things to make this happen. But really
its much more important to listen to the tests to make things clear
and simple.

In this case perhaps there is an ElectricityService class asking to be
born.

HTH

Andrew

It seems obvious now that you point it out. So in rspec-land, what’s
the stylistically appropriate way to test this? Stub .any_class()?

–
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–

4

Justin Ko wrote in post #1040632:

What are the failed expectations? Just paste it.

You’ve identified the problem (see below), but to answer your question:

  1. Wizard electricity credentials with valid credentials should spawn
    external loader
    Failure/Error: @wizard.electricity_loader.should_receive(:start)
    (#Wizard::ElectricityLoader:0x000001029bc140).start(any args)
    expected: 1 time
    received: 0 times

    ./spec/models/wizard_spec.rb:181:in `block (4 levels) in <top

(required)>’

Are you sure that @wizard.electricity_service is returning the same
object on each call? If a database call is being made, there’s a good
chance it is returning a different object (which has not mocks).

Ah! I think that’s the culprit – @wizard.electricity_service invokes a
db call:

class Wizard < ActiveRecord::Base
def electricity_service
premise.metered_services.where(:natural_resource_id =>
NaturalResource::ELECTRICITY.id)
end
end

It seems obvious now that you point it out. So in rspec-land, what’s
the stylistically appropriate way to test this? Stub .any_class()?