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import pytest |
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3
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4
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@pytest.fixture |
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5
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def subclass_registry_metaclass(): |
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from so_magic.utils import SubclassRegistry |
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return SubclassRegistry |
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9
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10
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@pytest.fixture |
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def assert_correct_class_creation(subclass_registry_metaclass): |
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def assert_class_creation(user_class): |
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assert type(user_class) == subclass_registry_metaclass |
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assert hasattr(user_class, 'subclasses') |
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assert hasattr(user_class, 'create') |
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assert hasattr(user_class, 'register_as_subclass') |
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assert user_class.subclasses == {} |
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return assert_class_creation |
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@pytest.fixture |
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def register_class(subclass_registry_metaclass): |
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def _register_class(subclass_id: str, inherit=False): |
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class ParentClass(metaclass=subclass_registry_metaclass): |
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pass |
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if inherit: |
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@ParentClass.register_as_subclass(subclass_id) |
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class Child(ParentClass): |
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pass |
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else: |
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@ParentClass.register_as_subclass(subclass_id) |
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class Child: |
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pass |
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child_instance = ParentClass.create(subclass_id) |
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return {'class_registry': ParentClass, 'child': Child, 'child_instance': child_instance} |
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return _register_class |
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42
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@pytest.fixture |
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def use_metaclass(register_class, assert_correct_metaclass_behaviour): |
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is_instance = {True: lambda classes: isinstance(classes['child_instance'], classes['class_registry']), |
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False: lambda classes: not isinstance(classes['child_instance'], classes['class_registry'])} |
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def _use_metaclass_in_scenario(subclass_id: str, inherit=False): |
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classes = register_class(subclass_id, inherit=inherit) |
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assert_correct_metaclass_behaviour(classes, subclass_id) |
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assert is_instance[inherit] |
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return classes['child_instance'], classes['child'], classes['class_registry'] |
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return _use_metaclass_in_scenario |
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53
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54
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@pytest.fixture |
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def assert_correct_metaclass_behaviour(): |
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def assert_metaclass_behaviour(classes, subclass_id): |
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assert classes['class_registry'].subclasses[subclass_id] == classes['child'] |
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assert type(classes['child_instance']) == classes['child'] |
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assert isinstance(classes['child_instance'], classes['child']) |
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return assert_metaclass_behaviour |
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61
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62
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63
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def test_metaclass_usage(subclass_registry_metaclass, assert_correct_class_creation): |
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class ParentClass(metaclass=subclass_registry_metaclass): |
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pass |
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assert_correct_class_creation(ParentClass) |
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70
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def test_subclass_registry(use_metaclass): |
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child1_instance1, Child1, ParentClass = use_metaclass('child1', inherit=True) |
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non_existent_identifier = 'child2' |
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exception_message_regex = \ |
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f'Bad "{str(ParentClass.__name__)}" subclass request; requested subclass with identifier ' \ |
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f'{non_existent_identifier}, but known identifiers are ' \ |
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rf'\[{", ".join(subclass_identifier for subclass_identifier in ParentClass.subclasses.keys())}\]' |
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80
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with pytest.raises(ValueError, match=exception_message_regex): |
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ParentClass.create(non_existent_identifier) |
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child1_instance2, Child2, ParentClass2 = use_metaclass('child2', inherit=False) |
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assert ParentClass.subclasses['child1'] == Child1 |
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boromir674 /
so-magic
