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from importlib.metadata import entry_points
from unittest import TestCase
from class_registry import EntryPointClassRegistry, RegistryKeyError
from test import Bulbasaur, Charmander, Mew, PokemonFactory, Squirtle
from test.helper import DummyDistributionFinder
def setUpModule():
# Inject a distribution that defines some entry points.
DummyDistributionFinder.install()
def tearDownModule():
DummyDistributionFinder.uninstall()
class EntryPointClassRegistryTestCase(TestCase):
def test_happy_path(self):
"""
Loading classes automatically via entry points.
See ``dummy_package.egg-info/entry_points.txt`` for more info.
"""
registry = EntryPointClassRegistry('pokemon')
fire = registry['fire']
self.assertIsInstance(fire, Charmander)
self.assertIsNone(fire.name)
grass = registry.get('grass')
self.assertIsInstance(grass, Bulbasaur)
self.assertIsNone(grass.name)
water = registry.get('water', name='archibald')
self.assertIsInstance(water, Squirtle)
self.assertEqual(water.name, 'archibald')
# The 'psychic' entry point actually references a function, but it
# works exactly the same as a class.
psychic = registry.get('psychic', 'snuggles')
self.assertIsInstance(psychic, Mew)
self.assertEqual(psychic.name, 'snuggles')
def test_branding(self):
"""
Configuring the registry to "brand" each class/instance with its
corresponding key.
"""
registry = EntryPointClassRegistry('pokemon', attr_name='poke_type')
try:
# Branding is applied immediately to each registered class.
self.assertEqual(getattr(Charmander, 'poke_type'), 'fire')
self.assertEqual(getattr(Squirtle, 'poke_type'), 'water')
# Instances, too!
self.assertEqual(registry['fire'].poke_type, 'fire')
self.assertEqual(registry.get('water', 'phil').poke_type, 'water')
# Registered functions and methods can't be branded this way,
# though...
self.assertFalse(
hasattr(PokemonFactory.create_psychic_pokemon, 'poke_type'),
)
# ... but we can brand the resulting instances.
self.assertEqual(registry['psychic'].poke_type, 'psychic')
self.assertEqual(registry.get('psychic').poke_type, 'psychic')
finally:
# Clean up after ourselves.
for cls in registry.values():
if isinstance(cls, type):
try:
delattr(cls, 'poke_type')
except AttributeError:
pass
def test_len(self):
"""
Getting the length of an entry point class registry.
"""
# Just in case some other package defines pokémon entry
# points (:
expected = len(list(entry_points(group='pokemon')))
# Quick sanity check, to make sure our test pokémon are
# registered correctly.
self.assertGreaterEqual(expected, 4)
registry = EntryPointClassRegistry('pokemon')
self.assertEqual(len(registry), expected)
def test_error_wrong_group(self):
"""
The registry can't find entry points associated with the wrong group.
"""
# Pokémon get registered (unsurprisingly) under the ``pokemon`` group,
# not ``random``.
registry = EntryPointClassRegistry('random')
with self.assertRaises(RegistryKeyError):
registry.get('fire')
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