Charla sobre pruebas unitarias en django

1. Pruebas Unitarias con Django
Tomás Henríquez tchenriquez@gmail.com
2-11-2012

2. Historia de las pruebas
en el software
http://clearspecs.com/joomla15/downloads/ClearSpecs16V01_GrowthOfSoftwareTest.pdf

3. Historia de las pruebas
Período orientado al Debugging
(antes - 1956)

4. Historia de las pruebas
Período orientado a la demostación
(1957 - 1978)

5. Historia de las pruebas

6. Historia de las pruebas
Período orientado a la destrucción
(1979 - 1982)

7. Historia de las pruebas
Período orientado a la evaluación
(1983 - 1987)

8. Historia de las pruebas
“Ninguna técnica puede garantizar software
sin errores, sin embargo, un conjunto de
técnicas cuidadosamente elegidas para un
proyecto en específico puede ayudar a
asegurar el desarrollo y mantenimiento de
software de calidad para un proyecto”

9. Historia de las pruebas
Período orientado a la prevención
(1988 - Hoy)

10. Pruebas Unitarias

11. Pruebas
¿Cómo uno usualmente prueba
su código?

12. Pruebas
¿Qué problemas tiene
el debugging?

13. Pruebas
¿Cómo persistir
estas pruebas?

14. Pruebas
¡NO ES FÁCIL!

15. Pruebas
¡NO ES FÁCIL!
● Carga de datos para la prueba
● No debe afectar la base de datos
● Super rápidas

16. Sheet Got Serious

17. Carga de datos
FIXTURES

18. Carga de datos
class Profession(models.Model):
name = models.CharField(max_length=30, unique=True)
specialist = models.CharField(max_length=30, blank=True)

19. Carga de datos
[
{
"pk": 1,
"model": "my_app.profession",
"fields": {
"name": "panadero",
"specialist": "pizza",
}
},
{
"pk": 2,
"model": "my_app.profession",
"fields": {
"name": "forever_alone",
...
]

20. Carga de datos
class Profession(models.Model):
name = models.CharField(max_length=30, unique=True)
specialist = models.CharField(max_length=30, blank=True)
full_time = models.BooleanField(default=False) <----

21. Carga de datos
[
{
"pk": 1,
"model": "my_app.profession",
"fields": {
"name": "panadero",
"specialist": "pizza",
"full_time": false, <--- Ay no.....
}
},
{
"pk": 2,
"model": "my_app.profession",
"fields": {
"name": "forever_alone",
...
]

22. Carga de datos
[
{
"pk": 1,
"model": "my_app.profession",
"fields": {
"name": "panadero",
"specialist": "pizza",
"full_time": false, <--- Ay no.....
}
},
{
"pk": 2,
"model": "my_app.profession",
"fields": {
"name": "forever_alone",
...
]

23. Carga de datos
FIXTURES
¿Para qué son buenos?

24. Carga de datos
Estructura del App
my_app/
__init__.py
models.py
fixtures/base.json <------
tests.py

25. Carga de datos
class UserTest(TestCase):
fixtures = ['base.json']
def setUp(self):
pass
def tearDown(self):
pass
def test_coolness(self):
# usuario con id == 1 existe gracias al fixture
user = User.objects.get(id=1)
self.assertTrue(user.is_cool, False)
user.become_a_hipster()
self.assertTrue(user.is_cool, True)

26. Carga de datos
Factories
https://github.com/dnerdy/factory_boy

27. Carga de datos
Factories
●
Organizado <------

28. Carga de datos
from django.db import models
class Receipt(models.Model):
user_id = fields.IntegerField()
merchant = fields.CharField(max_length=30)
class ReceiptItem(models.Model):
name = models.CharField(max_length=30)
quantity = models.IntegerField(default=1)
alert_sent = models.BooleanField(default=False)
receipt = models.ForeignKey(Receipt)
class Attach(models.Model):
name = models.CharField(max_length=30)
item = models.ForeignKey(ReceiptItem)

29. Carga de datos
class ReceiptTest(TestCase):
fixtures = ['base.json']
def setUp(self):
rep = Receipt(user_id=1, merchant='mami')
rep.save()
ri = ReceiptItem(name='medias', quantity=2,
receipt=rep)
ri.save()
att = Attach(name='foto_de_juanita.jpg', item=ri)
att.save()
...

30. Carga de datos
class ReceiptTest(TestCase):
fixtures = ['base.json']
def setUp(self):
rep = Receipt(user_id=1, merchant='mami')
rep.save()
ri = ReceiptItem(name='medias', quantity=2)
ri.save()
att = Attach(name='foto_de_juanita.jpg', item=ri)
att.save()
...

31. Carga de datos
Estructura del App
my_app/
__init__.py
models.py
fixtures/base.json
factories.py <-------
tests.py

32. Carga de datos
class ReceiptFactory(factory.Factory):
FACTORY_FOR = Receipt
user_id = 1
merchant = "mami"
class ReceiptItemFactory(factory.Factory):
FACTORY_FOR = ReceiptItem
name = factory.Sequence(lambda n: 'item-%s' % n)
quantity = 1
receipt = ReceiptFactory()
class AttachmentFactory(factory.Factory):
FACTORY_FOR = Attachment
name = factory.Sequence(lambda n: 'attachment-%s' % n)
item = ReceiptItemFactory()

33. Carga de datos
class ReceiptTest(TestCase):
fixtures = ['base.json']
def setUp(self):
ReceiptFactory()
...

34. Carga de datos

35. Carga de datos

36. Carga de datos

37. Carga de datos
Factories
●
Organizado
●
Flexible <-------

38. Carga de datos
class ReceiptTest(TestCase):
fixtures = ['base.json']
def setUp(self):
# No se crea en base de datos
ReceiptFactory.build()
...

39. Carga de datos
class ReceiptTest(TestCase):
fixtures = ['base.json']
def setUp(self):
# Crear muchos objects
ReceiptFactory.create_batch(5)
...

40. Carga de datos
Factories
●
Organizado
●
Flexible
●
Facil de migrar
<-------

41. Carga de datos
from mongoengine.document import Document, EmbeddedDocument
class Attach(EmbeddedDocument):
name = fields.StringField(required=True)
class ReceiptItem(EmbeddedDocument):
name = fields.StringField(required=True)
quantity = fields.DecimalField(default=Decimal(1))
alert_sent = fields.BooleanField(default=False)
attachments = fields.ListField(fields.EmbeddedDocumentField(Attach))
class Receipt(Document):
user_id = fields.IntField(required=True)
merchant = fields.StringField(required=True)
items = fields.ListField(fields.EmbeddedDocumentField(ReceiptItem))

42. Carga de datos
class AttachmentFactory(factory.Factory):
FACTORY_FOR = Attachment
name = factory.Sequence(lambda n: 'attachment-%s' % n)
class ReceiptItemFactory(factory.Factory):
FACTORY_FOR = ReceiptItem
name = factory.Sequence(lambda n: 'item-%s' % n)
quantity = 1
Attachments = [AttachmentFactory.build()]
class ReceiptFactory(factory.Factory):
FACTORY_FOR = Receipt
user_id = 2
merchant = "Amazon"
items = [ReceiptItemFactory.build()]

43. Carga de datos
class ReceiptTest(TestCase):
fixtures = ['base.json']
def setUp(self):
ReceiptFactory()
...

44. MOCKERS
http://labix.org/mocker
http://www.voidspace.org.uk/python/mock/

45. Mockers

46. Mockers
def tweet(tokens, body):
consumer = oauth.Consumer(TWITTER_KEY,
settings.TWITTER_SECRET)
token = oauth.Token(tokens.oauth,
tokens.oauth_secret)
client = oauth.Client(consumer, token)
header, body = client.request("http://api.twitter.com/1/statuses/"
"update.json", "POST", body="status=%s" % body)
if header['status'] == '401':
return False, ('Twitter account not authorized.'
' Please connect your account again.')
body = json.loads(body)
if header['status'] != '200':
return False, body.get('error', 'Unknown Twitter error')
return True, sbody['id_str']

47. Mockers
from mocker import Mocker, ARGS, KWARGS
class TweetTest(TestCase):
fixtures = ['base.json']
def setUp(self):
mocker = Mocker()
mock_client = mocker.replace('oauth.Client')
mock_client.request(ARGS, KWARGS)
mocker.response({'code': 200,
'text': 'OK', 'description': 'Success!'}) <----
self.mocker = mocker
def test_tweet(self):
user = User.objects.get(id=1)
self.assertTrue(user.tweets, 0)
with self.mocker:
res = tweet(user.tokens,
'esto es un Tweet de prueba')
self.assertEquals(res, True)

48. Mockers
from mocker import Mocker, ARGS, KWARGS
class TweetTest(TestCase):
fixtures = ['base.json']
def setUp(self):
mocker = Mocker()
mock_client = mocker.replace('oauth.Client')
mock_client.request(ARGS, KWARGS)
mocker.throw(ConnectionException) <----
self.mocker = mocker
def test_tweet(self):
user = User.objects.get(id=1)
# Podemos manejar la excepcion?
with self.mocker:
tweet(user.tokens,
'esto es un Tweet de prueba')

49. Buenas y Malas
Practicas

50. Tips
¿Hacer Pruebas antes de lanzar código?

51. Tips
MAL
def test_gmail(self):
expected_msg = {
'subject': 'SeamlessWeb Order',
'plain': '[image: Seamless Web Logo] ...' # MAL
'html': 'n<table width="640" border=...' # MAL
}
m = Message.objects.get(pk=1)
msg = {
'subject': m.subject,
'html': m.body_mimetype_html,
'plain': m.body_mimetype_plain
}
msg = strip_forwarding(msg)
self.assertEqual(msg['subject'], expected_msg['subject'])
self.assertEqual(msg['plain'], expected_msg['plain'])
self.assertEqual(msg['html'], expected_msg['html'])

52. Tips
BIEN
def test_gmail(self):
strips = ('---------- Forwarded message ----------',
'Fwd: ', 'From: ', 'Date: ', 'Subject: ', 'To: ')
checks = {'subject': u'SeamlessWeb Order'}
msg = strip_forwarding(msg)
# Validar que los valores sean los esperados
for key, val in checks.items():
self.assertEqual(val, msg[key])
# Asegurar que estos valores no se encuentren en el email
for strip in strips:
for m in msg.values():
self.assertNotIn(strip, m)

53. Tips
No hacer multiples pruebas en una función

54. Tips
MAL
def test_emails(self):
strips = ('---------- Forwarded message ----------',
'Fwd: ', 'From: ', 'Date: ', 'Subject: ', 'To: ')
checks = {'subject': u'SeamlessWeb Order'}
gmail, aol, hotmail = message.objects.all()[:2]
msgs = (strip_forwarding(gmail),
strip_forwarding(aol), strip_forwarding(hotmail))
for msg in msgs:
for key, val in checks.items():
self.assertEqual(val, msg[key])
for strip in strips:
for m in msg.values():
self.assertNotIn(strip, m)

55. Tips
BIEN
def test_gmail(self):
strips = ('---------- Forwarded message ----------',
'Fwd: ', 'From: ', 'Date: ', 'Subject: ', 'To: ')
checks = {'subject': u'SeamlessWeb Order'}
gmail = message.objects.get(id=1)
msgs = strip_forwarding(gmail)
for key, val in checks.items():
self.assertEqual(val, msg[key])
for strip in strips:
for m in msg.values():
self.assertNotIn(strip, m)
def test_aol(self):
strips = ('---------- Forwarded message ----------',...

56. Tips
BIEN
def test_gmail(self):
strips = ('---------- Forwarded message ----------',
'Fwd: ', 'From: ', 'Date: ', 'Subject: ', 'To: ')
checks = {'subject': u'SeamlessWeb Order'}
gmail = message.objects.get(id=1)
msgs = strip_forwarding(gmail)
for key, val in checks.items():
self.assertEqual(val, msg[key])
for strip in strips:
for m in msg.values():
self.assertNotIn(strip, m)
def test_aol(self):
strips = ('---------- Forwarded message ----------',...

57. Tips
Pruebas por Aserción
def test_gmail_checks(self):
checks = {'subject': u'SeamlessWeb Order'}
gmail = message.objects.get(id=1)
msgs = strip_forwarding(gmail)
for key, val in checks.items():
self.assertEqual(val, msg[key]) <---- Asercion
def test_gmail_strips(self):
strips = ('---------- Forwarded message ----------',
'Fwd: ', 'From: ', 'Date: ', 'Subject: ', 'To: ')
gmail = message.objects.get(id=1)
msgs = strip_forwarding(gmail)
for strip in strips:
for m in msg.values():
self.assertNotIn(strip, m) <---- Asercion

58. Tips
Pruebas por Acción
def test_gmail(self):
strips = ('---------- Forwarded message ----------',
'Fwd: ', 'From: ', 'Date: ', 'Subject: ', 'To: ')
checks = {'subject': u'SeamlessWeb Order'}
gmail = message.objects.get(id=1)
msgs = strip_forwarding(gmail) <---- ACCION
for key, val in checks.items():
self.assertEqual(val, msg[key])
for strip in strips:
for m in msg.values():
self.assertNotIn(strip, m)

59. Tips
Probar todas las ramas
def handle_coolness(self, user):
if user.is_cool:
do_cool_stuff(user)
else:
raise NotCoolDudeException

60. Pruebas de Integración

61. Pruebas de Integración
django client library
def test_view(self):
user = User.objects.get(id=1)
url = '/login/'
response = self.client.post(url, {
'username': user.username,
'password': 'fakybaby',
'timezone': 'America/Caracas'
}
self.assertEquals(response.status_code, 200)
self.assertEquals(response.cookies_set['logged_name'],
User.username)

62. Pruebas de Integración
django client library
def test_view(self):
user = User.objects.get(id=1)
url = '/login/'
response = self.client.post(url, {
'username': user.username,
'password': 'fakybaby',
'timezone': 'America/Caracas'
}
self.assertEquals(response.status_code, 200)
self.assertEquals(response.cookies_set['logged_name'],
User.username)

63. Pruebas de Integración
WebTest!
def test_view(self):
user = User.objects.get(id=1)
url = '/login/'
form = self.app.get(url).forms['login-form']
form['username'] = user.username
form['password'] = 'fakybaby'
response = form.submit().follow()
self.assertEquals(response.status_code, 200)
self.assertEquals(response.cookies_set['logged_name'],
user.username)

64. Continuous deployment
http://jenkins-ci.org/

65. Continuous Deployment
Integrado por django_jenkins
Correr Pruebas unitarias
Verificacion de codigo (Pep8, jslint, etc)
Reportes
Emails

66. Continuous Deployment
if len(sys.argv) > 1 and sys.argv[1] in ['test', 'jenkins']:
# test mongo db
MONGO_DBNAME = 'db_test'
db = mongoengine.connect(MONGO_DBNAME,
username=MONGO_USERNAME,
password=MONGO_PASSWORD,
host=MONGO_HOST,
port=MONGO_PORT, safe=True)
db.drop_database(MONGO_DBNAME) # drop entire database

67. ¿Preguntas?
@hazuek
tchenriquez@gmail.com
github.com/hassek