[rspec-users] [OT] Object Mother vs Test Data Builder (was Jay Fields' blog on developer testing)

Scott Taylor scott at railsnewbie.com
Thu Feb 5 14:36:30 EST 2009

> Nat points out that problems with Object Mother arise when people  
> start adding factory methods to deal with the edge cases, such as  
> ObjectMother.new_invoice_with_no_postal_code.  I totally agree that  
> this would be a problem since such abstraction results in hard to  
> follow tests (this is why I hate fixtures actually).  From the  
> projects I have worked on I haven't seen the Object Mother libs  
> abused this way and they are used more like a Test Data Builder.   
> The only difference I see is in implementation, meaning the ruby  
> libs tend to group all the factory methods on one object or module  
> just like Object Mother, while the pattern Nat describes uses a  
> separate builder class for each object.  I think this is really just  
> details though and results from Ruby's differences from Java.
> Any thoughts?  Are Ruby's Object Mothers really Test Data Builders?

Yeah, at least FixtureReplacement takes that stance, which is why I  
didn't call "Object Mother"


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