RSpec update_attributes expectation failing, even though update works

Question

I'm using what is largely a scaffold generated RSpec spec, which is failing but shouldn't be. Here is the spec:

describe "PUT update" do
    describe "with valid params" do
      it "updates the requested invoice" do


      invoice = Invoice.create!

       Invoice.any_instance.should_receive(:update_attributes).with({"number" => "MyString"  })
    put :update, {:id => invoice.id, :invoice => { "number" => "MyString" }}
  end

When the spec is run, one Invoice is created in the db, and is updated appropriately. However, I get this message and a fail:

RSpec::Mocks::MockExpectationError: (#<Mocha::ClassMethods::AnyInstance:0x653a9a8>).update_attributes({"number"=>"MyString"})
expected: 1 time with arguments: ({"number"=>"MyString"})
received: 0 times with arguments: ({"number"=>"MyString"})

Why is this failing?

Answer 1

At the risk of stating the obvious, since your getting a Mocha error, it seems to me you need to either disable Mocha or configure it for use with RSpec.

You can disable a gem by removing it from Gemfile and re-executing bundle install. Or you can add a 'require: false` argument when specifying the gem so that it doesn't autoload, per Bundler: What does :require => false in a Gemfile mean?

Instructions for configuring Mocha to work with RSpec are in https://relishapp.com/rspec/rspec-core/v/2-14/docs/mock-framework-integration/mock-with-mocha

Answer 2

I had a similar issue and I solved it by using expects instead of should_receive. You might just need to update it to use expects like the following.

describe "PUT update" do
  describe "with valid params" do
    it "updates the requested invoice" do
      invoice = Invoice.create!
      Invoice.any_instance.expects(:update_attributes).with({"number" => "MyString"  })
      put :update, {:id => invoice.id, :invoice => { "number" => "MyString" }}
    end
  end
end

Answer 3

Mocha, like many other mock frameworks, requires you to put your expectations before running the code under test.

Therefore, in your test, swap the two lines; i.e. call Invoice.create! after Invoice.any_instance.should_receive.