pytestify

A tool to automatically change unittest to pytest. Similar to unittest2pytest, but with a few more features and written using AST and tokenize, rather than lib2to3.

Big thanks to pyupgrade, which this project has learned from.

Installation

pip install pytestify

Usage

pytestify path/to/file.py

or

pytestify path/to/folder/

Optional arguments

• --keep-method-casing
• --with-count-equal

Please read over all changes that pytestify makes. It's a new package, so there are bound to be issues.

Implemented features

Test class names

Remove TestCase parent class, and make sure tests start with Test. We are keeping the test classes themselves, but you can remove them manually.

class TestThing(unittest.TestCase):  # class TestThing:
class TestThing(TestCase, ClassB):   # class TestThing(ClassB):
class ThingTest(unittest.TestCase):  # class TestThing:
class Thing(unittest.TestCase):      # class TestThing:

Setup / teardowns

def setUp(self):          # def setup_method(self):
def tearDown(self):       # def teardown_method(self):
def setUpClass(self):     # def setup_class(self):
def tearDownClass(self):  # def teardown_class(self):

Asserts

Rewrite unittest assert methods using the assert keyword.

# asserting one thing
self.assertTrue(a)       # assert a
self.assertFalse (a)     # assert not a
self.assertIsNone(a)     # assert a is None
self.assertIsNotNone(a)  # assert a is not None

# asserting two things
self.assertEqual(a, b)      # assert a == b
self.assertNotEqual(a, b)   # assert a != b
self.assertIs(a, b)         # assert a is b
self.assertIsNot(a, b)      # assert a is not b
self.assertIn(a, b)         # assert a in b
self.assertNotIn(a, b)      # assert a not in b
self.assertListEqual(a, b)  # assert a == b
self.assertDictEqual(a, b)  # assert a == b
self.assertSetEqual(a, b)   # assert a == b
self.assertGreater(a, b)    # assert a > b
self.assertLess(a, b)       # assert a < b
self.assertGreaterEqual(a, b)  # assert a >= b
self.assertLessEqual(a, b)  # assert a <= b
self.assertRegex(a, b)      # assert a.search(b)
self.assertNotRegex(a, b)   # assert not a.search(b)

self.assertAlmostEqual(a, b)
#   assert a == pytest.approx(b)
self.assertAlmostEqual(a, b, places=2)
#   assert a == pytest.approx(b, abs=0.01)
self.assertAlmostEquals(a, b, delta=2)
#   assert a == pytest.approx(b, abs=2)


# improves the assert if reasonable
self.assertEqual(a, None)   # assert a is None
self.assertEqual(a, True)   # assert a is True


# error messages
self.assertTrue(a, msg='oh no!')  # assert a, 'oh no!'

Multi-line asserts

Since assert (a == b, 'err') is equivalent to asserting a tuple, and thus is always True.

self.assertEqual(    # assert a == \
    a,               #     b
    b,
)

self.assertEqual(    # assert a == \
    a,               #     b, \
    b,               #     'oh no!'
    msg='oh no!'
)

camelCase to snake_case

Disable this behavior with --keep-method-casing

def testThing(self):      # def test_thing(self):
def testHTTPThing(self):  # def test_httpthing(self):

assertCountEqual

The assertCountEqual rewrite is risky, so opt-in with pytest path/to/file --with-count-equal.

self.assertItemsEqual(a, b)  # assert sorted(a) == sorted(b)
self.assertCountEqual(a, b)  # assert sorted(a) == sorted(b)

Note that pytest has no version of either of these methods. See this thread for more information. You can also use unittest's implementation.

Exceptions

self.assertRaises(OSError)             # pytest.raises(OSError)
self.assertWarns(OSError)              # pytest.warns(OSError)
with self.assertRaises(OSError) as e:  # with pytest.raises(OSError) as e
with self.assertWarns(OSError) as e:   # with pytest.warns(OSError) as e

Skipping / Expecting failure

# decorated
@unittest.skip('some reason')    # @pytest.mark.skip('some reason')
@unittest.skipIf(some_bool)      # @pytest.mark.skipif(some_bool)
@unittest.skipUnless(some_bool)  # @pytest.mark.skipif(not some_bool)
@unittest.expectedFailure        # @pytest.mark.xfail

# not decorated
unittest.skip('some reason')     # pytest.skip('some reason')
unittest.skipTest('some reason') # pytest.skip('some reason')
unittest.fail('some reason')     # pytest.fail('some reason')