rspec users - Jul 2007 - Multiple calls to a class method

Hi

Just wrote myself a Date.extract_from_rails_hash to handle parsing  
the "date(1i)", "date(2i)" parameters created in the
controller
params.  I''ve got a method that needs to call this either once or  
twice, depending on the contents of the form (one section of the form  
is rendered conditionally).  So I had two specs for the case where  
the second form section is included:

it "..." do
   Date.should_receive(:extract_from_rails_hash).
     with(REQUEST_ARGS_WITH_FINANCE_AGREEMENT 
[:vehicle], :registration_date).
     and_return(Date.new(2006, 12, 1))
   # ...
end

it "..." do
   Date.should_receive(:extract_from_rails_hash).
     with(REQUEST_ARGS_WITH_FINANCE_AGREEMENT 
[:finance_agreement], :start_date).
     and_return(Date.new(2006, 12, 4))
   # ...
end

In each of these specs I only care about one of the calls, but they  
fail because the Date method is being called twice, and it reports  
the other call as an error.

What is the thinking behind this?  I know you shouldn''t have  
unspecified code, but it seems restrictive to force all calls to a  
method to be covered in the same example.

Thanks
Ashley

On 7/10/07, Ashley Moran <work at ashleymoran.me.uk>
wrote:
> Hi
>
> Just wrote myself a Date.extract_from_rails_hash to handle parsing
> the "date(1i)", "date(2i)" parameters created in the
controller
> params.  I''ve got a method that needs to call this either once or
> twice, depending on the contents of the form (one section of the form
> is rendered conditionally).  So I had two specs for the case where
> the second form section is included:
>
> it "..." do
>    Date.should_receive(:extract_from_rails_hash).
>      with(REQUEST_ARGS_WITH_FINANCE_AGREEMENT
> [:vehicle], :registration_date).
>      and_return(Date.new(2006, 12, 1))
>    # ...
> end
>
> it "..." do
>    Date.should_receive(:extract_from_rails_hash).
>      with(REQUEST_ARGS_WITH_FINANCE_AGREEMENT
> [:finance_agreement], :start_date).
>      and_return(Date.new(2006, 12, 4))
>    # ...
> end
>
> In each of these specs I only care about one of the calls, but they
> fail because the Date method is being called twice, and it reports
> the other call as an error.
>
> What is the thinking behind this?  I know you shouldn''t have
> unspecified code, but it seems restrictive to force all calls to a
> method to be covered in the same example.
This is pretty standard in mocking frameworks. In fact, your
frustration was Jim Weirich''s motivation for writing Flexmock, so you
may want to give that framework a shot.

Using RSpec''s mocks, the way I get around this is to stub the call in
before(:each) and the mock the call in the example:

describe "something" do
  before(:each) do
    Date.stub!(:extract_from_rails_hash)
  end
  it "..." do
    Date.should_receive(:extract_from_rails_hash).
      with(one_set_of_args).
      and_return(Date.new(2006, 12, 1))
    # ...
  end

  it "..." do
    Date.should_receive(:extract_from_rails_hash).
      with(another_set_of_args).
      and_return(Date.new(2006, 12, 1))
    # ...
  end
end

This tells the Date class object to ignore all extract_from_rails_hash
messages except the one that you are interested in in th example.

David
>
> Thanks
> Ashley
>
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>

On 10 Jul 2007, at 13:16, David Chelimsky wrote:
> This is pretty standard in mocking frameworks. In fact, your
> frustration was Jim Weirich''s motivation for writing Flexmock, so
you
> may want to give that framework a shot.
<snip>
> This tells the Date class object to ignore all extract_from_rails_hash
> messages except the one that you are interested in in th example.
Thanks for clearing that up.  I might take a look at FlexMock some  
time and see how it compares.  I don''t run into this problem often so  
it was more of a philosophical question but nice to know there''s at  
least a workaround.

Regards Ashley