Slides da palestra sobre py.test apresentada no TDC 2015 na trilha de Python Slides of my talk about py.test presented at TDC 2015 in the Python track. http://github.com/erickwilder/pytest-talk

1. pytest

2. por quê?

3. ~100K L

4. menos verboso

5. import unittest
class SomethingTestCase(unittest.TestCase):
def test_something(self):
self.assertNotEqual('foobar'.upper(), 'FOOBAR')
if __name__ == '__main__':
unittest.main()

6. import unittest
class SomethingTestCase(unittest.TestCase):
def test_something(self):
self.assertNotEqual('foobar'.upper(), 'FOOBAR')
if __name__ == '__main__':
unittest.main()

7. import unittest
class SomethingTestCase(unittest.TestCase):
def test_something(self):
assert 'foobar'.upper() != 'FOOBAR'
if __name__ == '__main__':
unittest.main()

8. import unittest
class SomethingTestCase(unittest.TestCase):
def test_something(self):
assert 'foobar'.upper() != 'FOOBAR'
if __name__ == '__main__':
unittest.main()

9. import unittest
class SomethingTestCase(unittest.TestCase):
def test_something(self):
assert 'foobar'.upper() != 'FOOBAR'

10. import unittest
class SomethingTestCase(unittest.TestCase):
def test_something(self):
assert 'foobar'.upper() != 'FOOBAR'

11. import unittest
def test_something():
assert 'foobar'.upper() != 'FOOBAR'

12. def test_something():
assert 'foobar'.upper() != 'FOOBAR'

13. import unittest
class SomethingTestCase(unittest.TestCase):
def test_something(self):
self.assertNotEqual('foobar'.upper(), 'FOOBAR')
if __name__ == '__main__':
unittest.main()

14. linhas: 6 > 2

15. 18K L

16. relatórios melhores

17. self.assertEqual('foobar', 'foobaz')

18. FAIL: test_something (__main__.SomethingTestCase)
------------------------------------------------------------------
Traceback (most recent call last):
File "test_something_verbose.py", line 9, in test_something
self.assertEqual('foobar', 'foobaz')
AssertionError: 'foobar' != 'foobaz'
------------------------------------------------------------------
Ran 1 test in 0.000s
FAILED (failures=1)

19. assert 'foobar' == 'foobaz'

20. def test_something():
> assert 'foobar' == 'foobaz'
E assert 'foobar' == 'foobaz'
E - foobar
E ? ^
E + foobaz
E ? ^

21. self.assertEqual({'a': 0, 'b': 1, 'c': 0},
{'a': 0, 'b': 2, 'd': 0})

22. ==================================================================
FAIL: test_something (__main__.SomeThingTestCase)
------------------------------------------------------------------
Traceback (most recent call last):
File "test_dict_verbose.py", line 9, in test_something
{'a': 0, 'b': 2, 'd': 0})
AssertionError: {'c': 2, 'a': 0, 'b': 1} != {'d': 0, 'a': 0, 'b': 2}
- {'a': 0, 'b': 1, 'c': 2}
? ^ ^ ^
+ {'a': 0, 'b': 2, 'd': 0}
? ^ ^ ^
------------------------------------------------------------------
Ran 1 test in 0.001s
FAILED (failures=1)

23. assert {'a': 0, 'b': 1, 'c': 0} == {'a': 0, 'b': 2, 'd': 0})

24. def test_something():
> assert {'a': 0, 'b': 1, 'c': 2} == {'a': 0, 'b': 2, 'd': 2}
E assert {'a': 0, 'b': 1, 'c': 2} == {'a': 0, 'b': 2, 'd': 2}
E Omitting 1 identical items, use -v to show
E Differing items:
E {'b': 1} != {'b': 2}
E Left contains more items:
E {'c': 2}
E Right contains more items:
E {'d': 2}
E Use -v to get the full diff

25. fixtures

26. def test_address():
...

27. def test_address(address):
assert address.country == 'Brazil'

28. import pytest
@pytest.fixture
def address():
return Address('Av. Paulista', 'São Paulo', 'SP', 'Brazil')
def test_address(address):
assert address.country == 'Brazil'

29. import pytest
@pytest.fixture
def address():
return Address('Av. Paulista', 'São Paulo', 'SP', 'Brazil')
@pytest.fixture
def place(address):
return Place(name='MASP', address=address)
def test_place_street(place):
assert place.address.street == 'Av. Paulista'

30. conftest.py

31. def test_place_street(place):
assert place.address.street == 'Av. Paulista'

32. @pytest.fixture
def country():
return ‘Brazil’
@pytest.fixture
def address(country):
return Address('Av. Paulista', 'São Paulo', 'SP', country)

33. import pytest
@pytest.fixture(params=['Brazil', 'Germany'])
def country(request):
return request.param
def test_something(address):
assert address.country != 'United States'

34. fixture scope

35. import pytest
@pytest.fixture(scope='session')
def session_app():
from example.app import create_app
return create_app()
@pytest.yield_fixture
def app(session_app):
ctx = session_app.test_request_context()
ctx.push()
yield session_app
ctx.pop()

36. from flask import url_for
def test_requires_app_context(app):
url_for('.home') == '/'
def test_config(app): # Same app used
assert 'SQLALCHEMY_DATABASE_URI' in app.config

37. assertion helpers

38. def test_config(app):
assert 'SQLALCHEMY_DATABASE_URI' in app.config

39. app = <Flask 'example.app'>
def test_config(app):
> assert 'SQLALCHEMY_DATABASE_URI' in app.config
E assert 'SQLALCHEMY_DATABASE_URI' in <Config {'JSON_SORT_KEYS': True,
'SERVER_NAME': None, 'TESTING': False, 'PRESERVE_CONTEXT_ON_EXCEPTION': None,
'DEBUG'...ple.app', 'SESSION_COOKIE_SECURE': False, 'USE_X_SENDFILE': False,
'PREFERRED_URL_SCHEME': 'http', 'SECRET_KEY': None}>
E + where <Config {'JSON_SORT_KEYS': True, 'SERVER_NAME': None, 'TESTING':
False, 'PRESERVE_CONTEXT_ON_EXCEPTION': None, 'DEBUG'...ple.app',
'SESSION_COOKIE_SECURE': False, 'USE_X_SENDFILE': False, 'PREFERRED_URL_SCHEME':
'http', 'SECRET_KEY': None}> = <Flask 'example.app'>.config

40. import pytest
def assert_has_config(app, config_key):
__tracebackhide__ = True
if config_key not in app.config:
found_keys = 'n'.join('- {}'.format(key) for key in app.config.keys())
pytest.fail('"{}" config key not found. Found this instead:n'
'{}'.format(config_key, found_keys))

41. app = <Flask 'example.app'>
def test_config_with_helper(app):
> assert_has_config(app, 'SQLALCHEMY_DATABASE_URI')
E Failed: "SQLALCHEMY_DATABASE_URI" config key not found. Found this instead:
E - TESTING
E - JSON_AS_ASCII
E - SESSION_COOKIE_HTTPONLY
E - PRESERVE_CONTEXT_ON_EXCEPTION
E - SESSION_COOKIE_NAME
E - APPLICATION_ROOT
...
E - SESSION_COOKIE_PATH
E - DEBUG

42. ad populum

43. plugins

44. pytest-xdist
pytest-cache
pytest-django

45. Resumo:
- menos verboso
- relatórios melhores
- fixtures
- assertion helpers
- comunidade

46. twitter.com/erickwilder
github.com/erickwilder
thanks!github.com/erickwilder/pytest-talk
Agradecimento especial a Cesar Canassa por me ensinar tanto sobre py.test