Test driven development in Django framework

[jyria]

What is your experience? Is it worth it, and is it possible?

I tried it and found it quite difficult to follow guideline of unit testing -- testing a unit of code, a class for example. Maybe Im just ignorant, but I didnt see, how can I create registration app only with unit tests. The only way I could drive implementation with tests was using more like an integration testing approach: calling requests with data and asserting that new user was registered and that form was valid/invalid etc, but this goes against TDD as I understand it. So should I not worry about pure "unit testing" approach and use django client http request to validate RegistrationForm. Or I should write unit tests for RegistrationForm class?

[Javier Guerra Giraldez]

TDD is not unit-testing

https://www.google.com/webhp?q=tdd%20is%20not%20unit%20testing


in short, it's like you've found: the tests you easily get with TDD
are more (but not exactly) like integration tests, because you test
features, not units. The "test isolated units" mantra of unit-testing
requires different work. There's nothing wrong in adding 'real'
unit-tests, but it's not required to do effective TDD.

I guess that since unittesting became so well known so long ago,
almost all test frameworks (including Python's and Django's) call
their base test class "UnitTest", but they're not; they're just tests.
you make them feature tests, or integration tests, or unit tests, or
whatever kind of test.

now, about the pros/cons of unit-testing vs. other kinds of tests.....
that's a whole debate that i'm not going to touch.

--
Javier

[Mike Dewhirst]

On 6/09/2012 3:04am, Javier Guerra Giraldez wrote:
> On Wed, Sep 5, 2012 at 7:46 AM, jyria <jyr...@gmail.com> wrote:
>> What is your experience? Is it worth it, and is it possible?
>>
>> I tried it and found it quite difficult to follow guideline of unit testing
>> -- testing a unit of code, a class for example. Maybe Im just ignorant, but
>> I didnt see, how can I create registration app only with unit tests. The
>> only way I could drive implementation with tests was using more like an
>> integration testing approach: calling requests with data and asserting that
>> new user was registered and that form was valid/invalid etc, but this goes
>> against TDD as I understand it. So should I not worry about pure "unit
>> testing" approach and use django client http request to validate
>> RegistrationForm. Or I should write unit tests for RegistrationForm class?
>
> TDD is not unit-testing

Here is a lovely diagram I found recently - probably by following a link
someone posted here - which shows the TDD process with unit tests and
acceptance tests.

IMO it covers pretty much everything in the universe ...

http://www.methodsandtools.com/archive/attready3.jpg

[jyria]

Thank you for reply,

I have been using your tutorial to learn TDD in django. One of the best I have found so far. You also talk about "unit tests" and thats what is confusing. As I understand, your tutorial examples are not unit tests in the strict meaning of the term.

You have a great tutorial and I have learned a lot of them. Maybe too much focus on admin and polls app for me. I would have liked to see something different and new. What about running you selenium functional tests in a acceptance testing framework?

I would love to see your tutorials for intermediate/advanced level.

On Thursday, September 6, 2012 1:57:08 PM UTC+3, Harry P wrote:

Hi there,

I work for a bunch of XP fanatics, so we do quite religious TDD in our Python/Django development.   We start with functional/acceptance tests, which we write using Selenium, driving a real web browser, and following a test script that is essential a user story.  We then write unit tests that we can run using a python manage.py test.

I've written a "TDD for beginners" tutorial, that covers both of these types of test:

http://www.tdd-django-tutorial.com/

I'd love any comments, feedback, suggestions?

rgds,
Harry

[Harry P]

Hey, glad to hear someone's been found it useful!

re: whether my unit tests are unit tests or not... some people have a very restrictive definition of what a unit test is - they want it to be 100% isolated from other tests, always mock out the filesystem and the database, etc.  That's fine, but we tend to find it's a bit OTT, and a slightly more relaxed approach is more productive.   Ultimately, I'm writing two types of test - some high-level tests that test the behaviour of the app from the user's point of view - so call them system tests, or functional tests, or acceptance tests, or whatever you will, but their purpose is to check the system actually works.  The other type of test is low-level, they test the behaviour of individual functions, classes etc, and their purpose is to help you think about your code before you write it, to think through edge cases and to help write correct code.

So, to me, the important thing is that you have those two types of test, and that they help you achieve those two different objectives.  Finer details of terminology or practices to do with mocking, stubbing etc are up to personal preferences really.

cheers,
hp

[Steven Cummings]

I think when people say "unit" tests to mean fully isolated tests, what they really mean is *whitebox* tests. You define the size of the unit under test and context runs from full isolation (whitebox test) to full integration/user-experience (blackbox test)
--
Steven

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