Testing¶

Testing with unittest¶

class MyTests(unittest.TestCase):
  def setUp(self):
      self.some_value = 23

  def test_addition(self):
      self.assertEqual(2 + self.some_value, 25)

 def test_exception(self):
   with self.assertRaises(ValueError):
       raise ValueError()

Testing with nose¶

Nose can use unittest tests but you want do more with nose tests

my Tests():
  def setup(self):
    self.some_value = 23

  # assumes function runs without failure
  def test_addition(self):
    assert self.some_value + 2 == 25

  def test_addition_with_nose(self):
    import nose
    nose.tools.assert_equals(self.some_value + 2, 25)

  @raises(ValueError)
  def test_exception(self):
    raise ValueError()

use nosy to automatically run all tests if code changes

pip install nosy
nosy

check code coverage of your unittests

pip install coverage
nosetests --with-coverage

testing performance

# test fails if it runs longer than 0.2 seconds
@timed(0.2)
def test_something():
  pass

run profiler on every tested unit

nosetests --with-profile

get a pdb on test failures

nosetests --pdb-failures

get output in xUnit format (usefull for e.g. Jenkins)

nosetests --with-xunit --xunit-file=testresults.xml

Integrate nose into setuptools

setup (
  # ...
  test_suite = 'nose.collector'
)

Doctests¶

Use nose to run Doctests

def some_function(a, b):
    """
    >>> some_function(2, 3)
    5
    """
    return a + b

nosetests --with-doctest

Mocking¶

Using nose and mock

@mock.patch('some_module.nasty_method', lambda x: True)
def test_nasty_method():
  assert some_module.nasty_method()

Using mock without nose

from mock import Mock

m = SomeModule()
m.nasty_method = Mock(return_value=42)

Using flexmock

flexmock(SomeObject).should_receive('some_method').and_return('some', 'values')