Dennis, It would be great to receive your ideas about how to use mocks in this case. Feel free to add any comment directly in the screencast at Vimeo (http://vimeo.com/19591202) Thank you! 2013/6/7 Dennis Schetinin <chaetal@gmail.com>
As for me, the StringCalculator kata is a very good (or better to say nearly perfect) demo of a classic TDD approach: small and fast steps, live objects⦠really nice!
Though I see (feel?) some issues⦠mostly about factoring-out new classes without tests (yes, that was refactoring⦠but still), I believe, that's beyond classic approach and only top-down TDD with mocks may help to keep TDD pure here. (I've scheduled a task for detailed exploration of how mocks can be used here to provide "seamless" TDD in this case.)
So, this screencast is a great lesson on TDD in Smalltalk.
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Best regards,
Dennis Schetinin
2013/6/7 Rafael Luque <rafael.luque.leiva@gmail.com>
Hi Dennis,
What do you think about the approach shown in this screencast: http://www.pharocasts.com/2011/02/stringcalculator-kata.html ?
I'm far away from being an Smalltalk developer, but I tried to show a TDD process to solve this simple kata.
Rafael Luque
2013/6/7 Dennis Schetinin <chaetal@gmail.com>
I don't remember exactly where and when, but I think we've discussed the Laser Game tutorial already. I told this before, and I (after reviewing the tutorial again) should repeat it again: actually, this tutorial doesn't show TDD. I can explain my opinion in detail if someone's interested, but in general, that's simply an up-front design approach with some automatic testing. It's not even "Test-First" approach most of time.
Disclaimer: I don't mean the tutorial and/or the design approach used there are bad. I like this tutorial. It's really very good: it shows many aspects for Smalltalk programing, it shows how to use debugger and inspectors properly. I borrowed many ideas from there for my Smalltalk programming course⦠It's just not TDD, not "pure" TDD at least.
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Best regards,
Dennis Schetinin
2013/6/7 <btc@openinworld.com>
Paul Davidowitz wrote:
It seems to me that a big reason for developing via writing tests first (Test Driven Development) is that the tests serve as a debugging tool -- if a test breaks, then the last piece of (non-test) code that change is likely the culprit. But with the powerful debugging environment that comes with Smalltalk, I am wondering of the utility of TDD (TDD is big in the Ruby camp perhaps for a reason). After all, writing and re-writing the tests becomes quite a non-trivial chore (not to mention that the tests themselves could be buggy). So my question: Is it ok in Smalltalk to write tests afterwards? Is it even perhaps recommended?
- Paul
Actually some Smalltalk'ers consider the debugger a major facilitator of TDD by mostly coding from within the debugger. 1. Before writing any application code, write a test. 2. Execute that test straight away. Of course it fails because you haven't written any application code. 3. Up comes the debugger - now "from within the debugger" add the application code needed to satisfy the test. 4. Repeat.
A good demonstration of this is Stephan Wessels' Laser Game tutorial [1] (but you'll temporarily need to revert to Squeak 3.9 to do it) cheers -ben