The document discusses test doubles and frameworks for programming test double behavior. It provides examples of using pyDoubles to program common test double behaviors like returning hardcoded values or raising exceptions in response to method calls on the test double. It also discusses other test double frameworks like Mockito, JMock, Moq, and PHPUnit.

1. Test Doubles
Rubén Bernárdez
www.rubenbp.com
@rubenbpv
#aos2011

2. ¿Por qué usamos dobles?
El colaborador:
class Communicator():
def send_email(self, address, total_savings):
suponemos_que_esto_envia_un_email = True
El SUT (System Under Test):
class SavingsService():
def __init__(self, communicator):
self.communicator = communicator
def analyze_month(self, month_savings):
calculation = month_savings[0] + month_savings[1]
self.communicator.send_email('savings@iexpertos.com', calculation)

3. Pruébalo cobarde! … pecador!...
class Communicator():
def send_email(self, address, total_savings):
suponemos_que_esto_envia_un_email = True
class SavingsService():
def __init__(self, communicator):
self.communicator = communicator
def analyze_month(self, month_savings):
calculation = month_savings[0] + month_savings[1]
self.communicator.send_email('savings@iexpertos.com', calculation)
class LoFlipoEnEl_AOS(unittest.TestCase):
def test_report_correcto_es_enviado_a_la_central(self):
communicator = spy(Communicator())
month_savings = [1234,1276435]
service = SavingsService(communicator)
service.analyze_month(month_savings)
assert_that(communicator.send_email).was_called()

4. ¿Mock o Spy?
class LoFlipoEnEl_AOS(unittest.TestCase):
def test_al_menos_es_enviado_a_la_central(self):
communicator = spy(Communicator())
month_savings = [1234,1276435]
service = SavingsService(communicator)
service.analyze_month(month_savings)
assert_that(communicator.send_email).was_called()
def test_se_envia_a_la_central_y_nada_mais(self):
communicator = mock(Communicator())
expect_call(communicator.send_email)
month_savings = [1234,1276435]
service = SavingsService(communicator)
service.analyze_month(month_savings)
communicator.assert_that_is_satisfied()

5. ¿Qué test se romperá?
class Communicator():
def send_email(self, address, total_savings):
suponemos_que_esto_envia_un_email = True
def post_savings(self, total_savings):
suponemos_que_esto_llama_a_un_webservice = True
class SavingsService():
def __init__(self, communicator):
self.communicator = communicator
def analyze_month(self, month_savings):
calculation = month_savings[0] + month_savings[1]
self.communicator.send_email('savings@iexpertos.com', calculation)
self.communicator.post_savings(calculation)

6. Un diseño distinto... ¿Ahora qué hacemos?
class Communicator():
def send_email(self, address, total_savings):
suponemos_que_esto_envia_un_email = True
class AccountRepository():
def month_savings(self):
suponemos_que_esto_devuelve_de_bd_los_ahorros = True
class SavingsService():
def __init__(self, communicator, repository):
self.communicator = communicator
self.repository = repository
def analyze_month(self):
month_savings = self.repository.month_savings()
calculation = month_savings[0] + month_savings[1]
self.communicator.send_email('savings@iexpertos.com', calculation)

7. Mejor Stub que Spy esta vez! fistro!
class SavingsService():
def __init__(self, communicator, repository):
self.communicator = communicator
self.repository = repository
def analyze_month(self):
month_savings = self.repository.month_savings()
calculation = month_savings[0] + month_savings[1]
self.communicator.send_email('savings@iexpertos.com', calculation)
class LoFlipoEnEl_AOS(unittest.TestCase):
def test_si_hay_report_envialo_a_la_central(self):
communicator = spy(Communicator())
repository = stub(AccountRepository())
when(repository.month_savings).then_return([1234,1276435])
service = SavingsService(communicator, repository)
service.analyze_month(month_savings)
assert_that(communicator.send_email).was_called()

8. Tests frágiles VS legibilidad
Classic VS Mockist

9. Test doubles frameworks
 ¿Qué más comportamientos se pueden
programar en los dobles de test? Con qué
frameworks?
 pyDoubles
 Mockito
 Jmock
 Moq
 Rhino.Mocks
 PHPUnit
 GoogleMock

10. pyDoubles.org
Made with TDD and open source!
 when(obj.method).with_args(1).then_return(1000)
 when(obj.method).then_raise(ApplicationException())
 when(obj.method).then_return(1000)
 expect_call(obj.method).with_args(1)
 expect_call(obj.method).with_args(1, ANY_ARG)
 assert_that(obj.method).was_called().with_args(1)
 when(obj.method).with_args(
str_containing(”abc”)).then_return(1)
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11. iExpertos.com
 Formación para equipos de desarrollo:
 Iniciación a TDD y TDD Avanzado
 eXtreme Programming a fondo (XP)
 Coaching
 Desarrollamos contigo:
 Dos iExpertos en tu empresa desde el arranque
del proyecto.
 Formación y desarrollo, todo en uno.