Rails: problem setting expectations on mock model in RSpec

rspecruby-on-rails

I am trying to set expectations on a mocked ActiveRecord model. I have created the following example, which should pass based on the documentation I can find.

it "should pass given the correct expectations" do
  payment = mock_model(Payment)
  payment.should_receive(:membership_id).with(12)
  payment.membership_id = 12
end

It is failing with the error "…Mock 'Payment_1004' received unexpected message :membership_id= with (12)"

I realize I am testing the mocking framework, I am just trying to understand how to setup expectations.

Best Answer

You're setting the expectation on the wrong method name - :membership_id is the "getter", :membership_id= is the "setter". The correct line would be:

payment.should_receive(:membership_id=).with(12)

Related Solutions

Ruby-on-rails – How to add multiple should_receive expectations on an object using RSpec

Multiple expectations are not a problem at all. What you're running into are ordering problems, given your specific args on unordered expectations. Check this page for details on ordering expectations.

The short story is that you should add .ordered to the end of each of your expectations.

Rspec mocks: verify expectations in it “should” methods

I'm going to take another whack at this, because it's clear from the initial set of answers and responses that there was some confusion about what you are trying to accomplish. Let me know if this is closer to what you are trying to do.

describe Foo, "when frobbed" do
  before :all do
    @it = Foo.new

    # Making @bar a null object tells it to ignore methods we haven't 
    # explicitly stubbed or set expectations on
    @bar = stub("A Bar").as_null_object
    Bar.stub!(:new).and_return(@bar)
  end

  after :each do
    @it.frob!
  end

  it "should zap a Bar" do
    @bar.should_receive(:zap!)
  end

  it "should also frotz the Bar" do
    @bar.should_receive(:frotz!)
  end
end

Incidentally, although it works I'm not a big fan of the Bar.stub!(:new) pattern; I usually prefer to pass collaborators in via optional arguments, e.g. @it.frob!(@bar). When not given an explicit argument (e.g. in the production code), the collaborator can be defaulted: def frob!(bar=Bar.new). This keeps the tests a little less bound to internal implementation.

Best Answer

Related Solutions

Ruby-on-rails – How to add multiple should_receive expectations on an object using RSpec

Rspec mocks: verify expectations in it “should” methods

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