An example of using a python MetaClass for Data Driven testing

README.rst

An example of using python metaclasses to perform data driven tests.

nosetests test_metaclass.py
test_baz_exists (tests.cli.test_foo.TestMetaClass) ... ok
test_greater_than_zero_1 (tests.cli.test_foo.TestMetaClass) ... ok
test_greater_than_zero_2 (tests.cli.test_foo.TestMetaClass) ... ok
test_greater_than_zero_3 (tests.cli.test_foo.TestMetaClass) ... ok
test_greater_than_zero_4 (tests.cli.test_foo.TestMetaClass) ... ok
Ran 5 tests in 0.001s
OK

test_metaclass.py

import unittest

from ddt import data
from ddt import ddt


class MetaTest(type):
    """
    Metaclass to tweak test classes dynamically
    """
    def __new__(cls, name, bases, dic):
        """Add test methods to new classes"""

        _klass = super(MetaTest, cls).__new__(cls, name, bases, dic)

        setattr(_klass, "test_greater_than_zero", cls.test_greater_than_zero)

        return _klass

    @staticmethod
    @data(1, 2, 3, 4)
    def test_greater_than_zero(cls, value):
        """Simple test"""
        cls.assertTrue(value > 0)


class Base(unittest.TestCase):
    """Base class for all tests"""

    @classmethod
    def setUpClass(cls):
        """Adds a baz attribute to test classes"""
        cls.baz = "Bazinga"


@ddt
class TestMetaClass(Base):
    """A simple test class"""

    __metaclass__ = MetaTest

    def test_baz_exists(self):
        """Checks that baz is not None"""
        self.assertTrue(self.baz)