Rspec - stub module method

Question

How can I stub a method within a module:

module SomeModule
    def method_one
        # do stuff
        something = method_two(some_arg)
        # so more stuff
    end

    def method_two(arg)
        # do stuff
    end
end

I can test method_two in isolation fine.

I would like to test method_one in isolation too by stubbing the return value of method_two:

shared_examples_for SomeModule do
    it 'does something exciting' do
        # neither of the below work
        # SomeModule.should_receive(:method_two).and_return('MANUAL')
        # SomeModule.stub(:method_two).and_return('MANUAL')

        # expect(described_class.new.method_one).to eq(some_value)
    end
end

describe SomeController do
    include_examples SomeModule
end

The specs in SomeModule that are included in SomeController fail because method_two throws an exception (it tries to do a db lookup that has not been seeded).

How can I stub method_two when it is called within method_one?

what do you expect from this module? to be a mixin or to call method from it at class level like: `SomeModule.foo` ? — apneadiving, Aug 20 '13 at 12:19
Take heart, George. Downvotes on questions are a generally bad idea, in my opinion, but the good news is that inappropriate ones frequently stimulate countervailing upvotes, with a net rep win for you and no net vote impact. — Peter Alfvin, Aug 20 '13 at 13:53
In addition to @apneadving's question, it's not clear what the relationship of the module to the controller in the code you're trying to test. Also, it's not clear to me what passing a class name to `shared_examples_for` does, as I've only seen a string used as an argument in the documentation as a way to invoke it. — Peter Alfvin, Aug 20 '13 at 14:15
In any event, if your controller mixes in that module, you need to stub the controller instance methods, not the module class method as you've tried to do. — Peter Alfvin, Aug 20 '13 at 14:17

score 5 · Answer 1 · edited May 23 '17 at 12:02

5

allow_any_instance_of(M).to receive(:foo).and_return(:bar)

Is there a way to stub a method of an included module with Rspec?

This approach works for me

edited May 23 '17 at 12:02

Community

1
1

answered Jun 11 '15 at 12:31

Tyler Aleksandrovich

51
1
1

score 3 · Accepted Answer · answered Sep 20 '13 at 18:22

3

shared_examples_for SomeModule do
  let(:instance) { described_class.new }

  it 'does something exciting' do
    instance.should_receive(:method_two).and_return('MANUAL')
    expect(instance.method_one).to eq(some_value)
  end
end

describe SomeController do
  include_examples SomeModule
end

answered Sep 20 '13 at 18:22

kristinalim

3,459
18
27

18

Please try to include some explanation on what's going on and your reasoning behind this. – kettlepot Feb 22 '14 at 11:02

Rspec - stub module method

2 Answers2