rspec users - Mar 2008 - mocking successive return values

I''m having a problems mocking successive return values.  I
don''t know
if I''m doing something wrong or if this is a limitation of rspec  
mocks.  Any ideas of what I may be doing wrong?

I''m trying to test the generate_quote_number method.  It generates a  
quote number, looks to see if it is in the db already.  If it is, it  
calls itself to try again.  I want to test that it looks in the  
database for matching numbers until it finds one which does not exist  
already.

## The code
  def generate_quote_number
     quote_num = "MMQ#{self.random_string}-001"
     if Policy.find(:first, :conditions => ["quote_number = ?",  
quote_num])
       quote_num = generate_quote_number
     end
     quote_num
   end

   def random_string(size=8)
      # return a random string
   end


For the test, I simply lookup 3 existing quote numbers, append nil to  
the end (for a total of 4)
## The test
   it "should not generate a duplicate quote number" do
     existing_quote_numbers = Policy.find(:all).map{|p| p.quote_number} 
[0,3]
      
@policy_service 
.should_receive 
(:random_string 
).with 
(:no_args 
).exactly(4).times.and_return(existing_quote_numbers.concat([nil]))
     @policy_service.generate_quote_number
   end

##  The result
should not generate a duplicate quote number
Mock ''Service::Base'' expected :random_string with (no args) 4
times,
but received it once

I verified "and_return" is actually returning the array rather than an
individual element of the existing_quote_numbers array which makes  
sense, but what about this?
http://rspec.rubyforge.org/svn/branches/dogfood/spec/spec/mocks/mock_spec.rb

specify "should use a list of return values for successive calls" do
          
@mock.should_receive(:multi_call).twice.with(:no_args).and_return([8,  
12])
         @mock.multi_call.should_equal 8
         @mock.multi_call.should_equal 12
         @mock.__verify
end

Any feedback on how to properly test this is much appreciated.

Thanks,
Doug


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I''m having a problems mocking successive return values.  I
don''t know if I''m
doing something wrong or if this is a limitation of rspec mocks.  Any ideas
of what I may be doing wrong?

I''m trying to test the generate_quote_number method.  It generates a
quote
number, looks to see if it is in the db already.  If it is, it calls itself
to try again.  I want to test that it looks in the database for matching
numbers until it finds one which does not exist already.

## The code
 def generate_quote_number
    quote_num = "MMQ#{self.random_string}-001"
    if Policy.find(:first, :conditions => ["quote_number = ?",
quote_num])
      quote_num = generate_quote_number
    end
    quote_num
  end

  def random_string(size=8)
     # return a random string
  end


For the test, I simply lookup 3 existing quote numbers, append nil to the
end (for a total of 4)
## The test
  it "should not generate a duplicate quote number" do
    existing_quote_numbers = Policy.find(:all).map{|p| p.quote_number}[0,3]

@policy_service.should_receive(:random_string).with(:no_args).exactly(4).times.and_return(existing_quote_numbers.concat([nil]))
    @policy_service.generate_quote_number
  end

##  The result
should not generate a duplicate quote number
Mock ''Service::Base'' expected :random_string with (no args) 4
times, but
received it once

I verified "and_return" is actually returning the array rather than an
individual element of the existing_quote_numbers array which makes sense,
but what about this?
http://rspec.rubyforge.org/svn/branches/dogfood/spec/spec/mocks/mock_spec.rb

specify "should use a list of return values for successive calls" do
        @mock.should_receive(:multi_call).twice.with(:no_args).and_return([8,
12])
        @mock.multi_call.should_equal 8
        @mock.multi_call.should_equal 12
        @mock.__verify
end

Any feedback on how to properly test this is much appreciated.

Thanks,
Doug
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Doug Bryant wrote:
> I''m having a problems mocking successive return values.  I
don''t know
> if I''m doing something wrong or if this is a limitation of rspec 
> mocks.  Any ideas of what I may be doing wrong?
>
>
> For the test, I simply lookup 3 existing quote numbers, append nil to 
> the end (for a total of 4)
> ## The test
>   it "should not generate a duplicate quote number" do
>     existing_quote_numbers = Policy.find(:all).map{|p| 
> p.quote_number}[0,3]
>     
>
@policy_service.should_receive(:random_string).with(:no_args).exactly(4).times.and_return(existing_quote_numbers.concat([nil]))
>     @policy_service.generate_quote_number
>   end
>
You will need to have one expectation per return.  Try this:

  it "should not generate a duplicate quote number" do
    #expect
    Policy.find(:all).map{|p| p.quote_number}[0,3].concat([nil]).each do 
|existing_quote_number|
        
@policy_service.should_receive(:random_string).with(:no_args).once.and_return(existing_quote_number))
    end
    #when
    @policy_service.generate_quote_number
  end



-Ben

Thanks Ben.  I appreciate it.
Doug

On Wed, Mar 5, 2008 at 1:25 PM, Ben Mabey <ben at benmabey.com> wrote:
> Doug Bryant wrote:
> > I''m having a problems mocking successive return values.  I
don''t know
> > if I''m doing something wrong or if this is a limitation of
rspec
> > mocks.  Any ideas of what I may be doing wrong?
> >
> >
> > For the test, I simply lookup 3 existing quote numbers, append nil to
> > the end (for a total of 4)
> > ## The test
> >   it "should not generate a duplicate quote number" do
> >     existing_quote_numbers = Policy.find(:all).map{|p|
> > p.quote_number}[0,3]
> >
> >
>
@policy_service.should_receive(:random_string).with(:no_args).exactly(4).times.and_return(existing_quote_numbers.concat([nil]))
> >     @policy_service.generate_quote_number
> >   end
> >
>
> You will need to have one expectation per return.  Try this:
>
>  it "should not generate a duplicate quote number" do
>     #expect
>    Policy.find(:all).map{|p| p.quote_number}[0,3].concat([nil]).each do
> |existing_quote_number|
>
>
>
@policy_service.should_receive(:random_string).with(:no_args).once.and_return(existing_quote_number))
>    end
>    #when
>     @policy_service.generate_quote_number
>  end
>
>
>
> -Ben
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>
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On Wed, Mar 5, 2008 at 9:30 AM, Doug Bryant <doug+rspecuser at
netinlet.com> wrote:
@policy_service.should_receive(:random_string).with(:no_args).exactly(4).times.and_return(existing_quote_numbers.concat([nil]))
>      @policy_service.generate_quote_number
>   end
>
> ##  The result
> should not generate a duplicate quote number
> Mock ''Service::Base'' expected :random_string with (no
args) 4 times, but
> received it once
>
> I verified "and_return" is actually returning the array rather
than an
> individual element of the existing_quote_numbers array which makes sense
You need to splat em out:

and_return(*existing_quote_numbers.concat([nil]))

Pat

On Wed, Mar 5, 2008 at 2:17 PM, Pat Maddox <pergesu at gmail.com> wrote:
>
> You need to splat em out:
>
> and_return(*existing_quote_numbers.concat([nil]))
>
> Pat
>
Hi, Pat,

Just for my own edification and education, if you have a minute, could you
explain what this means and why you have to do it?

Thanks,
-Corey

-- 
http://www.coreyhaines.com
The Internet''s Premiere source of information about Corey Haines
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On Wed, Mar 5, 2008 at 12:06 PM, Corey Haines <coreyhaines at gmail.com>
wrote:
>
> On Wed, Mar 5, 2008 at 2:17 PM, Pat Maddox <pergesu at gmail.com>
wrote:
> >
> >
> > You need to splat em out:
> >
> >
> > and_return(*existing_quote_numbers.concat([nil]))
> >
> > Pat
> >
>
> Hi, Pat,
>
> Just for my own edification and education, if you have a minute, could you
> explain what this means and why you have to do it?
Basically it takes an array and splits it up.  Here''s a little irb
session that ought to demonstrate it.
>> def foo(val); p val; end
=> nil
>> a = [1,2,3]
=> [1, 2, 3]
>> foo(a)
[1, 2, 3]
=> nil
>> foo(*a)
ArgumentError: wrong number of arguments (3 for 1)
	from (irb):4:in `foo''
	from (irb):4

The method expects one argument.  When I pass it an array, everything
is fine because it only has one object.  However when I splat the
array, it splits it up into three distinct objects and tries to pass
it in, causing the method to blow up.

In RSpec, you specify multiple values to return by passing in multiple
objects.  An array is just one object, so the mock just returns it.
Splat it out and you''ve passed multiple values to and_return, causing
it to return them in succession.

* is called the splat operator and can be used to collect stuff in
addition to splitting stuff up.  Just google for "ruby splat operator"
to get lots of info.  Also you can define #to_splat on any object.

Pat

Wow! That is really cool. Thanks for the explanation, Pat.

-Corey
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