簡単な実装でParserTesterMetaclassの__init__を動かす

code:test_metaclass_example.py

from unittest import TestCase

class ParserTesterMetaclass(type):

def __init__(cls, name, bases, bodydict):

if name == "ParserTestCase":

return

class AddTests:

def __init__(self, tester_cls):

test_name = test_func.__name__

def wrapper(self, test_func=test_func):

# selfはtester引数に渡る

test_func(self)

setattr(tester_cls, test_name, wrapper)

def test_failures(self, tester):

# testerはunittest.TestCaseのサブクラスとして想定（assertRaisesやassertEqualメソッドを持つ）

with tester.assertRaises(TypeError):

3 + "3"

def test_successes(self, tester):

tester.assertEqual(3 + 3, 6)

tester.assertEqual("3" + "3", "33")

AddTests(cls)

ParserTestCase = ParserTesterMetaclass("ParserTestCase", (TestCase,), {})

class AwesomeTestCase(ParserTestCase):

...

class FabulousTestCase(ParserTestCase):

...

AwesomeTestCaseとFabulousTestCaseにはtest_failuresとtest_successesが生える

code:shell

$ python3.10 -m unittest test_metaclass_example.py -v

test_failures (test_metaclass_example.AwesomeTestCase) ... ok

test_successes (test_metaclass_example.AwesomeTestCase) ... ok

test_failures (test_metaclass_example.FabulousTestCase) ... ok

test_successes (test_metaclass_example.FabulousTestCase) ... ok

----------------------------------------------------------------------

Ran 4 tests in 0.000s

OK