From: cremes.devlist@...
Date: 2006-06-06T01:58:10+09:00
Subject: Re: Need help with TDD, stubs and mocks

On Jun 5, 2006, at 10:57 AM, Jim Weirich wrote:

> cr wrote:
>> 4. How do you test a method that utilizes an instance variable that
>> was set somewhere else? E.g. #methodA calculates @result. #methodB
>> retrieves @second_result. #methodC compares @result and  
>> @second_result.
>
> Construct your test case so that methodA and methodB are called before
> methodC does its work.
>
> Example:
>
>    def test_comparison
>      thing = Thing.new
>      thing.methodA
>      thing.methodB
>      assert_equal ExpectedResult, thing.methodC
>    end

Jim,

thanks for your response. I do need some additional clarification on  
this final point. The way I see your answer, you are NOT suggesting I  
pass instance variables as parameters. Instead, I should enforce the  
order of operations for my methods and allow them "global" (in this  
class instance) access to the instance variables.

I still see this as somewhat problematic if there is a long chain of  
"custody" in between where the instance variable gets set and where  
it gets used again by a later method. I'll have to think on this a  
bit more.

BTW, I really appreciated the distinctions you made on mocks versus  
stubs. I think I get it now. Now all I need to do is repeat this a  
thousand times to imprint it on my brain.

Time to test!

cr