Documentation about the returns method

Testing RSpec
1

Hi,

From the railscasts website source code, in the episodes_controller_spec
I read:

it “index action with search should search published episodes” do
Episode.expects(:search_published).with(‘foo’).returns(Episode.all)
get :index, :search => ‘foo’
end

Here are my questions:

  • What does the returns(Episode.all) mean?
  • Is it stubbing what the search_published method returns?
  • Is it useful to add the returns(Episode.all) method call here?
  • Whats the difference with and_return(Episode.all)?
  • Shouldn’t we only test for:
    Episode.expects(:search_published).with(‘foo’)?
2

Fernando P. wrote:

Hi,

From the railscasts website source code, in the episodes_controller_spec
I read:

it “index action with search should search published episodes” do
Episode.expects(:search_published).with(‘foo’).returns(Episode.all)
get :index, :search => ‘foo’
end

Here are my questions:

  • What does the returns(Episode.all) mean?
  • Is it stubbing what the search_published method returns?
  • Is it useful to add the returns(Episode.all) method call here?
  • Whats the difference with and_return(Episode.all)?
  • Shouldn’t we only test for:
    Episode.expects(:search_published).with(‘foo’)?

I also forgot to add:
What’s the difference between expects and should_receive? I can get my
head around it.

3

On Wed, Jan 14, 2009 at 3:53 PM, Fernando P. [email protected]
wrote:

Here are my questions:

  • What does the returns(Episode.all) mean?

This calls Episode.all one time and stores the result. When Episode
receives :search_publishe with ‘foo’, that’s what it returns. Make
sense?

  • Is it stubbing what the search_published method returns?

Yes

  • Is it useful to add the returns(Episode.all) method call here?

If you don’t, nothing will be returned. If the application code relies
on the return value, then it is definitely useful - necessary, in
fact.

  • Whats the difference with and_return(Episode.all)?

No semantic difference - different library (see below).

  • Shouldn’t we only test for:
    Episode.expects(:search_published).with(‘foo’)?

No - the returns statement is not part of the expectation - it’s the
value to return when search_published is received.

I also forgot to add:
What’s the difference between expects and should_receive? I can get my
head around it.

Two different mocking libraries:

spec/mocks:

Episode.should_receive(:search_published).with(‘foo’).and_return(Episode.all)

mocha (used in the screen cast):

Episode.expects(:search_published).with(‘foo’).returns(Episode.all)

HTH,
David

4

David C. wrote:

On Wed, Jan 14, 2009 at 3:53 PM, Fernando P. [email protected]
wrote:

Here are my questions:

  • What does the returns(Episode.all) mean?

Okay I get it now. Thank you very much.