Guide to TDD & Flight to BDD with python/django 

About Us Me: A humble student of the trade! You: ? 

What I won't do? ● Comparisons ● No Mocking/DocTests ● Opinions ● Conclusions 

What we will do? ● Overview ● Getting Started is Painful ● Unit testing django models, views, forms ● Integration testing with selenium ● The shift to BDD ● BDD Demo ● Q & A 

TDD - Initial Pain 

About the topic 

When & What & How 

A basic unittest import unittest2 class TestDemo(unittest2.TestCase): " A demo of simple unit test" def setup(self): self.char = 'a' def tearDown(self): del self.char def test_first_pass(self): "Asserting that the character is not b" self.assertNotEqual(self.char, 'b') def test_second_fail(self): "Making a false assertion" assert self.char != 'c' 

A good TDD sequence for a project 1. Write test for models a. the objects are being created and they have the desired relations as per specs b. the functions are returning correct values & manipulating db as per specs 2. Write test for forms - red, green a. states of forms b. perms. of good & bad forms, data 3. Write test for views a. response variable(200, 404) b. template & context variable c. behavior via decorator(@login_required etc.) 4. Write test for custom middlewares & template tags. 

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Fixture Management (& Namespaces) are one honking great idea -- let's do more of those! 

A sample fixture test from django_dynamic_fixture import G class ChoiceModelTest(TestCase): def test_choice_creation(self): # set up the values poll0 = G(Poll) poll1 = G(Poll) ch0 = G(Choice, poll=poll0) ch1 = G(Choice, poll=poll0) # test basic values polls_in_db = Poll.objects.all() poll_zero = polls_in_db[0] poll_one = polls_in_db[1] choices = Choice.objects.filter(poll = poll_zero) self.assertEquals(choices.count(), 4) ch_zero = choices[0] self.assertEquals(ch_zero.choice, ch0.choice) self.assertEquals(ch_zero.votes, ch0.votes) 

Test Runners 

Settings for nose test runner TEST_RUNNER = 'django_nose. NoseTestSuiteRunner' NOSE_ARGS = [ '--with-coverage', '--cover-package=polls', '--with-progressive', '--verbosity=0', '--with-fixture-bundling', ] 

Integration/Performance/System/Fun ctional/Web Tests 

Integ. test with Selenium 1. Get the browser 2. Simulate Behavior a. use selectors i. locate by name, id, xpath, hyperlink test ii. browser extensions b. trigger keypress/action 3. Assert 

Code 

Behavior Driven Development (Sapir Whorf Hypothesis ) 

BDD - GWT/Gherkin Feature: Run or Riot In order to test my bot's strength, As a bot developer, I want to program my bot's decision making. Scenario: Boring Opponent Given the bots network has been trained When attacked by RA-One Then the bot should kill the opponent Scenario: Legendary opponent Given the bot's network has been trained When attacked by Robot Then the bot should bow down in respect! http://dannorth.net/whats-in-a-story/ 

.....although that may not be obvious at first unless you're Dutch. 

BDD libraries ● Lettuce - /gabrielfalcao/lettuce ● Freshen - /rlisagor/freshen ● Behave - /jeamland/behave ● ...& counting.... (all above are format github.com/w+/w+) 

BDD - Demo 

Few more libraries ● Another full featured testing tool - ○ pytest.org ● WSGI testing ○ /pypi/WebTest ● Test Discovery: ○ /jezdez/django-discover-runner ● Better Assertion Messages: ○ /gabrielfalcao/sure 

Practicality beats Purity In practical, the difference between theory & practical, is greater than, the difference between theory & practical, in theory. 

Thanks & Questions?? ● Contact ○ at gamebit07 (twitter) ○ gamebit07 at gmail dot com