Dial T for Testing

A talk about testing and Django from the March 2014 DJUGL meetup.

Transcript

1. T
   testing
   for
   Dial
   

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2. David Winterbottom
   @codeinthehole
   /codeinthehole
   

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3. Tangent Labs
   @tangent_labs
   /tangentlabs
   

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4. django-oscar
   @django_oscar
   /tangentlabs/django-oscar
   

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5. View Slide

6. Nose
   Nose
   nose.readthedocs.org
   

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7. Django
   

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8. Dexterity
   

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9. Basics
   

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10. Run ALL the tests
    

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11. Run tests beneath path
    

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12. Run test module
    

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13. Run test class
    

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14. Run test method
    

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15. nosecomplete
    github.com/alonho/nosecomplete
    

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16. nosecomplete
    github.com/alonho/nosecomplete
    

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17. Stories
    

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18. Stories
    Work on a feature
    

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20. https://github.com/asdfasdf/spec
    Custom test runner
    

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21. https://github.com/asdfasdf/spec
    Testing one module
    

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22. https://github.com/asdfasdf/spec
    Spec plugin
    https://github.com/bitprophet/spec
    

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23. https://github.com/asdfasdf/spec
    BDD-style output
    

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24. class TestASignedInUser(WebTestCase):!
    !
    def setUp(self):!
    self.user = G(User)!
    self.order = factories.create_order(user=self.user)!
    !
    def test_can_see_their_email_address_on_the_profile_page(self):!
    profile_page = self.app.get(!
    reverse('customer:summary'), user=self.user)!
    self.assertTrue(self.email in profile_page.content)!
    !
    def test_can_update_their_name(self):!
    profile_form_page = self.app.get(!
    reverse('customer:profile-update'), user=self.user)!
    form = profile_form_page.forms['profile_form']!
    form['first_name'] = 'Barry'!
    form['last_name'] = 'Chuckle'!
    response = form.submit()!
    self.assertRedirects(response, reverse('customer:summary'))!
    !
    # Reload user!
    user = User.objects.get(id=self.user.id)!
    self.assertEquals("Barry", user.first_name)!
    self.assertEquals("Chuckle", user.last_name)!
    

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25. class TestASignedInUser(WebTestCase):!
    !
    def setUp(self):!
    self.user = G(User)!
    self.order = factoies.create_order(user=self.user)!
    !
    def test_can_see_their_email_address_on_the_profile_page(self):!
    profile_page = self.app.get(!
    reverse('customer:summary'), user=self.user)!
    self.assertTrue(self.email in profile_page.content)!
    !
    def test_can_update_their_name(self):!
    profile_form_page = self.app.get(!
    reverse('customer:profile-update'), user=self.user)!
    form = profile_form_page.forms['profile_form']!
    form['first_name'] = 'Barry'!
    form['last_name'] = 'Chuckle'!
    response = form.submit()!
    self.assertRedirects(response, reverse('customer:summary'))!
    !
    # Reload user!
    user = User.objects.get(id=self.user.id)!
    self.assertEquals("Barry", user.first_name)!
    self.assertEquals("Chuckle", user.last_name)!
    System under test
    

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26. class TestASignedInUser(WebTestCase):!
    !
    def setUp(self):!
    self.user = G(User)!
    self.order = factories.create_order(user=self.user)!
    !
    def test_can_see_their_email_address_on_the_profile_page(self):!
    profile_page = self.app.get(!
    reverse('customer:summary'), user=self.user)!
    self.assertTrue(self.email in profile_page.content)!
    !
    def test_can_update_their_name(self):!
    profile_form_page = self.app.get(!
    reverse('customer:profile-update'), user=self.user)!
    form = profile_form_page.forms['profile_form']!
    form['first_name'] = 'Barry'!
    form['last_name'] = 'Chuckle'!
    response = form.submit()!
    self.assertRedirects(response, reverse('customer:summary'))!
    !
    # Reload user!
    user = User.objects.get(id=self.user.id)!
    self.assertEquals("Barry", user.first_name)!
    self.assertEquals("Chuckle", user.last_name)!
    Specification
    

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27. Use-cases
    Work on a new feature
    Refactor a feature
    

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28. https://github.com/nose attribs/spec
    

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29. nose.readthedocs.org/en/latest/plugins/attrib.html
    Run tagged tests
    

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30. from nose.plugins.attrib import attr!
    !
    !
    @attr('shipping')!
    class TestFreeShippping(TestCase):!
    !
    def test_is_free_for_empty_basket(self):!
    ...!
    !
    !
    class TestFixedPriceShipping(TestCase):!
    !
    @attr(slow=True)!
    def test_returns_fixed_price_for_basket(self):!
    ...!
    

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31. from nose.plugins.attrib import attr!
    !
    !
    @attr('shipping')!
    class TestFreeShippping(TestCase):!
    !
    def test_is_free_for_empty_basket(self):!
    ...!
    !
    !
    class TestFixedPriceShipping(TestCase):!
    !
    @attr(slow=True)!
    def test_returns_fixed_price_for_basket(self):!
    ...!
    Wrap a class
    

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32. from nose.plugins.attrib import attr!
    !
    !
    @attr('shipping')!
    class TestFreeShippping(TestCase):!
    !
    def test_is_free_for_empty_basket(self):!
    ...!
    !
    !
    class TestFixedPriceShipping(TestCase):!
    !
    @attr(slow=True)!
    def test_returns_fixed_price_for_basket(self):!
    ...!
    Wrap a method
    

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34. Pattern match tests
    github.com/iElectric/nose-selecttests
    

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35. Use-cases
    Work on a new feature
    Refactor a feature
    Fix failing tests
    

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36. Fail fast
    

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37. Editor-friendly paths
    github.com/erikrose/nose-progressive
    

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38. PDB on failure
    

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39. Only re-run failed tests
    

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40. Use-cases
    Work on a new feature
    Refactor a feature
    Fix failing tests
    Ready to push?
    

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42. No plugins
    

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43. Parallelise
    

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44. Speed
    

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45. 0 4 8 12 16 20 24
    Focus / flow / “zone”
    Test suite time (seconds)
    

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46. 0 4 8 12 16 20 24
    Focus / flow / “zone”
    Test suite time (seconds)
    Pre-commit hook?
    

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47. 0 4 8 12 16 20 24
    Focus / flow / “zone”
    Test suite time (seconds)
    

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48. 0 4 8 12 16 20 24
    Test suite time (seconds)
    

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51. Scam?
    blog.thecodewhisperer.com/2010/10/16/integrated-tests-are-a-scam/
    

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52. import mock!
    from django.utils.functional import curry!
    !
    no_database = curry(!
    mock.patch, 'django.db.backends.util.CursorWrapper',!
    Mock(side_effect=RuntimeError(!
    "Using the database is not permitted")))!
    !
    !
    @no_database()!
    class AUnitTest(TestCase):!
    ...!
    http://bit.ly/126vPrt
    

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53. import mock!
    from django.utils.functional import curry!
    !
    no_database = curry(!
    mock.patch, 'django.db.backends.util.CursorWrapper',!
    Mock(side_effect=RuntimeError(!
    "Using the database is not permitted")))!
    !
    !
    @no_database()!
    class AUnitTest(TestCase):!
    ...!
    http://bit.ly/126vPrt
    Currying mock.patch!
    

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54. import mock!
    from django.utils.functional import curry!
    !
    no_database = curry(!
    mock.patch, 'django.db.backends.util.CursorWrapper',!
    Mock(side_effect=RuntimeError(!
    "Using the database is not permitted")))!
    !
    !
    @no_database()!
    class AUnitTest(TestCase):!
    ...!
    http://bit.ly/126vPrt
    Wrap classes/methods
    

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55. http://bit.ly/156c48x
    Number of tests
    Seconds
    

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56. PASSWORD_HASHERS =
    ['django.contrib.auth.hashers.MD5PasswordHasher']
    

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57. --processes=8
    

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58. http://bit.ly/2gZnhj
    Boy scout rule...
    

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59. Readability
    

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60. http://bit.ly/19ganRJ (Refactoring a Test)
    

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61. class TestBasket(TestCase):!
    !
    def test_add_items(self):!
    # Create products!
    product_class = ProductClass(!
    name="Books", require_shipping=True)!
    product1 = Product.objects.create(title="My first book")!
    product2 = Product.objects.create(title="My second book")!
    partner = Partner.objects.create(name="Book Partner")!
    stockrecord1 = StockRecord(!
    price_excl_tax=D('12.00'), partner=partner)!
    stockrecord2 = StockRecord(!
    price_excl_tax=D('14.00'), partner=partner)!
    !
    # Add to basket!
    basket = Basket()!
    basket.add(product1)!
    basket.add(product2)!
    !
    total = basket.total_excl_tax!
    !
    self.assertEqual(D('26.00'), total)!
    self.assertEqual(basket.num_lines, 2)!
    self.assertFalse(basket.is_empty)!
    

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62. class TestBasket(TestCase):!
    !
    def test_add_items(self):!
    # Create products!
    product_class = ProductClass(!
    name="Books", require_shipping=True)!
    product1 = Product.objects.create(title="My first book")!
    product2 = Product.objects.create(title="My second book")!
    partner = Partner.objects.create(name="Book Partner")!
    stockrecord1 = StockRecord(!
    price_excl_tax=D('12.00'), partner=partner)!
    stockrecord2 = StockRecord(!
    price_excl_tax=D('14.00'), partner=partner)!
    !
    # Add to basket!
    basket = Basket()!
    basket.add(product1)!
    basket.add(product2)!
    !
    total = basket.total_excl_tax!
    !
    self.assertEqual(D('26.00'), total)!
    self.assertEqual(basket.num_lines, 2)!
    self.assertFalse(basket.is_empty)!
    Bad naming
    

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63. class TestBasket(TestCase):!
    !
    def test_add_items(self):!
    # Create products!
    product_class = ProductClass(!
    name="Books", require_shipping=True)!
    product1 = Product.objects.create(title="My first book")!
    product2 = Product.objects.create(title="My second book")!
    partner = Partner.objects.create(name="Book Partner")!
    stockrecord1 = StockRecord(!
    price_excl_tax=D('12.00'), partner=partner)!
    stockrecord2 = StockRecord(!
    price_excl_tax=D('14.00'), partner=partner)!
    !
    # Add to basket!
    basket = Basket()!
    basket.add(product1)!
    basket.add(product2)!
    !
    total = basket.total_excl_tax!
    !
    self.assertEqual(D('26.00'), total)!
    self.assertEqual(basket.num_lines, 2)!
    self.assertFalse(basket.is_empty)!
    Heavy set-up
    

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64. class TestBasket(TestCase):!
    !
    def test_add_items(self):!
    # Create products!
    product_class = ProductClass(!
    name="Books", require_shipping=True)!
    product1 = Product.objects.create(title="My first book")!
    product2 = Product.objects.create(title="My second book")!
    partner = Partner.objects.create(name="Book Partner")!
    stockrecord1 = StockRecord(!
    price_excl_tax=D('12.00'), partner=partner)!
    stockrecord2 = StockRecord(!
    price_excl_tax=D('14.00'), partner=partner)!
    !
    # Add to basket!
    basket = Basket()!
    basket.add(product1)!
    basket.add(product2)!
    !
    total = basket.total_excl_tax!
    !
    self.assertEqual(D('26.00'), total)!
    self.assertEqual(basket.num_lines, 2)!
    self.assertFalse(basket.is_empty)!
    Noise
    

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65. class TestBasket(TestCase):!
    !
    def test_add_items(self):!
    # Create products!
    product_class = ProductClass(!
    name="Books", require_shipping=True)!
    product1 = Product.objects.create(title="My first book")!
    product2 = Product.objects.create(title="My second book")!
    partner = Partner.objects.create(name="Book Partner")!
    stockrecord1 = StockRecord(!
    price_excl_tax=D('12.00'), partner=partner)!
    stockrecord2 = StockRecord(!
    price_excl_tax=D('14.00'), partner=partner)!
    !
    # Add to basket!
    basket = Basket()!
    basket.add(product1)!
    basket.add(product2)!
    !
    total = basket.total_excl_tax!
    !
    self.assertEqual(D('26.00'), total)!
    self.assertEqual(basket.num_lines, 2)!
    self.assertFalse(basket.is_empty)!
    Unclear assertions
    

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66. class TestBasket(TestCase):!
    !
    def test_add_items(self):!
    # Create products!
    product_class = ProductClass(!
    name="Books", require_shipping=True)!
    product1 = Product.objects.create(title="My first book")!
    product2 = Product.objects.create(title="My second book")!
    partner = Partner.objects.create(name="Book Partner")!
    stockrecord1 = StockRecord(!
    price_excl_tax=D('12.00'), partner=partner)!
    stockrecord2 = StockRecord(!
    price_excl_tax=D('14.00'), partner=partner)!
    !
    # Add to basket!
    basket = Basket()!
    basket.add(product1)!
    basket.add(product2)!
    !
    total = basket.total_excl_tax!
    !
    self.assertEqual(D('26.00'), total)!
    self.assertEqual(basket.num_lines, 2)!
    self.assertFalse(basket.is_empty)!
    Sloppy coding
    

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67. class TestBasketTotal(TestCase):!
    !
    def setUp(self):!
    self.basket = Basket()!
    !
    def test_is_correct_after_adding_multiple_items(self):!
    products = [!
    factory.create_product(price_excl_tax=D('12.00')),!
    factory.create_product(price_excl_tax=D('14.00')),!
    ]!
    for product in products:!
    self.basket.add_product(product)!
    self.assertEqual(!
    D('12.00') + D('14.00'), self.basket.total_excl_tax)!
    

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68. class TestBasketTotal(TestCase):!
    !
    def setUp(self):!
    self.basket = Basket()!
    !
    def test_is_correct_after_adding_multiple_items(self):!
    products = [!
    factory.create_product(price_excl_tax=D('12.00')),!
    factory.create_product(price_excl_tax=D('14.00')),!
    ]!
    for product in products:!
    self.basket.add_product(product)!
    self.assertEqual(!
    D('12.00') + D('14.00'), self.basket.total_excl_tax)!
    Descriptive names
    

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69. class TestBasketTotal(TestCase):!
    !
    def setUp(self):!
    self.basket = Basket()!
    !
    def test_is_correct_after_adding_multiple_items(self):!
    products = [!
    factory.create_product(price_excl_tax=D('12.00')),!
    factory.create_product(price_excl_tax=D('14.00')),!
    ]!
    for product in products:!
    self.basket.add_product(product)!
    self.assertEqual(!
    D('12.00') + D('14.00'), self.basket.total_excl_tax)!
    Factory functions
    

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70. class TestBasketTotal(TestCase):!
    !
    def setUp(self):!
    self.basket = Basket()!
    !
    def test_is_correct_after_adding_multiple_items(self):!
    products = [!
    factory.create_product(price_excl_tax=D('12.00')),!
    factory.create_product(price_excl_tax=D('14.00')),!
    ]!
    for product in products:!
    self.basket.add_product(product)!
    self.assertEqual(!
    D('12.00') + D('14.00'), self.basket.total_excl_tax)!
    Intention revealing
    

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71. WebTest
    webtest.readthedocs.org/
    def test_contact_us(self):!
    home = self.app.get('/')!
    !
    # Fill in form!
    contact_us = home.click(linkid="contact_us_link")!
    form = contact_us.forms['profile_form']!
    form['name'] = 'Barry Chuckle'!
    form['query'] = 'To me?'!
    confirm = form.submit().follow()!
    !
    self.assertTrue('Thanks Barry' in confirm.content)!
    

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73. red
    green
    refactor
    

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74. failing test
    passing test
    clean test
    fast test
    

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75. no tests
    tests
    readable tests
    fast, readable tests
    

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76. •Test suite is there to help you
    •Make it clear and easy to read
    •Make it fast
    •Master your test runner
    TLDR
    

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77. •Write tests using the spec style
    •Use WebTest (not the Django
    client)
    Homework
    

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