diff options
| -rw-r--r-- | factory/base.py | 158 |
1 files changed, 114 insertions, 44 deletions
diff --git a/factory/base.py b/factory/base.py index 0a89e3f..9cc7fcb 100644 --- a/factory/base.py +++ b/factory/base.py @@ -23,37 +23,33 @@ import re import sys -from containers import AttributeBuilder, DeclarationDict, StubObject -from declarations import OrderedDeclaration +from factory import containers # Strategies - BUILD_STRATEGY = 'build' CREATE_STRATEGY = 'create' STUB_STRATEGY = 'stub' # Creation functions. Use Factory.set_creation_function() to set a creation function appropriate for your ORM. - DJANGO_CREATION = lambda class_to_create, **kwargs: class_to_create.objects.create(**kwargs) # Building functions. Use Factory.set_building_function() to set a building functions appropriate for your ORM. - NAIVE_BUILD = lambda class_to_build, **kwargs: class_to_build(**kwargs) MOGO_BUILD = lambda class_to_build, **kwargs: class_to_build.new(**kwargs) # Special declarations - FACTORY_CLASS_DECLARATION = 'FACTORY_FOR' # Factory class attributes - CLASS_ATTRIBUTE_DECLARATIONS = '_declarations' CLASS_ATTRIBUTE_ASSOCIATED_CLASS = '_associated_class' + # Factory metaclasses -def get_factory_base(bases): +def get_factory_bases(bases): + """Retrieve all BaseFactoryMetaClass-derived bases from a list.""" return [b for b in bases if isinstance(b, BaseFactoryMetaClass)] @@ -61,7 +57,10 @@ class BaseFactoryMetaClass(type): """Factory metaclass for handling ordered declarations.""" def __call__(cls, **kwargs): - """Create an associated class instance using the default build strategy. Never create a Factory instance.""" + """Override the default Factory() syntax to call the default build strategy. + + Returns an instance of the associated class. + """ if cls.default_strategy == BUILD_STRATEGY: return cls.build(**kwargs) @@ -72,24 +71,48 @@ class BaseFactoryMetaClass(type): else: raise BaseFactory.UnknownStrategy('Unknown default_strategy: {0}'.format(cls.default_strategy)) - def __new__(cls, class_name, bases, attrs, extra_attrs={}): - """Record attributes (unordered declarations) and ordered declarations for construction of - an associated class instance at a later time.""" + def __new__(cls, class_name, bases, attrs, extra_attrs=None): + """Record attributes as a pattern for later instance construction. + + This is called when a new Factory subclass is defined; it will collect + attribute declaration from the class definition. + + Args: + class_name (str): the name of the class being created + bases (list of class): the parents of the class being created + attrs (str => obj dict): the attributes as defined in the class + definition + extra_attrs (str => obj dict): extra attributes that should not be + included in the factory defaults, even if public. This + argument is only provided by extensions of this metaclass. - parent_factories = get_factory_base(bases) + Returns: + A new class + """ + + parent_factories = get_factory_bases(bases) if not parent_factories or attrs.get('ABSTRACT_FACTORY', False): - # If this isn't a subclass of Factory, don't do anything special. + # If this isn't a subclass of Factory, or specifically declared + # abstract, don't do anything special. return super(BaseFactoryMetaClass, cls).__new__(cls, class_name, bases, attrs) - declarations = DeclarationDict() + declarations = containers.DeclarationDict() - #Add parent declarations in reverse order. + # Add parent declarations in reverse order. for base in reversed(parent_factories): + # Import all 'public' attributes (avoid those starting with _) declarations.update_with_public(getattr(base, CLASS_ATTRIBUTE_DECLARATIONS, {})) + # Import attributes from the class definition, storing protected/private + # attributes in 'non_factory_attrs'. non_factory_attrs = declarations.update_with_public(attrs) + + # Store the DeclarationDict in the attributes of the newly created class non_factory_attrs[CLASS_ATTRIBUTE_DECLARATIONS] = declarations - non_factory_attrs.update(extra_attrs) + + # Add extra args if provided. + if extra_attrs: + non_factory_attrs.update(extra_attrs) return super(BaseFactoryMetaClass, cls).__new__(cls, class_name, bases, non_factory_attrs) @@ -103,46 +126,93 @@ class FactoryMetaClass(BaseFactoryMetaClass): Also, autodiscovery failed using the name '{1}' based on the Factory name '{2}' in {3}.""" + @classmethod + def _discover_associated_class(cls, class_name, attrs, inherited=None): + """Try to find the class associated with this factory. + + In order, the following tests will be performed: + - Lookup the FACTORY_CLASS_DECLARATION attribute + - If the newly created class is named 'FooBarFactory', look for a FooBar + class in its module + - If an inherited associated class was provided, use it. + + Args: + class_name (str): the name of the factory class being created + attrs (dict): the dict of attributes from the factory class + definition + inherited (class): the optional associated class inherited from a + parent factory + + Returns: + class: the class to associate with this factory + + Raises: + AssociatedClassError: If we were unable to associate this factory + to a class. + """ + own_associated_class = None + used_auto_discovery = False + + if FACTORY_CLASS_DECLARATION in attrs: + return attrs[FACTORY_CLASS_DECLARATION] + + factory_module = sys.modules[attrs['__module__']] + if class_name.endswith('Factory'): + # Try a module lookup + used_auto_discovery = True + associated_class_name = class_name[:-len('Factory')] + if associated_class_name: + # Class name was longer than just 'Factory'. + try: + return getattr(factory_module, associated_class_name) + except AttributeError: + pass + + # Unable to guess a good option; return the inherited class. + if inherited is not None: + return inherited + + # Unable to find an associated class; fail. + if used_auto_discovery: + raise Factory.AssociatedClassError( + FactoryMetaClass.ERROR_MESSAGE_AUTODISCOVERY.format( + FACTORY_CLASS_DECLARATION, + associated_class_name, + class_name, + factory_module,)) + else: + raise Factory.AssociatedClassError( + FactoryMetaClass.ERROR_MESSAGE.format( + FACTORY_CLASS_DECLARATION)) + def __new__(cls, class_name, bases, attrs): """Determine the associated class based on the factory class name. Record the associated class for construction of an associated class instance at a later time.""" - parent_factories = get_factory_base(bases) + parent_factories = get_factory_bases(bases) if not parent_factories or attrs.get('ABSTRACT_FACTORY', False): # If this isn't a subclass of Factory, don't do anything special. return super(FactoryMetaClass, cls).__new__(cls, class_name, bases, attrs) base = parent_factories[0] - inherited_associated_class = getattr(base, CLASS_ATTRIBUTE_ASSOCIATED_CLASS, None) - own_associated_class = None - used_auto_discovery = False + inherited_associated_class = getattr(base, + CLASS_ATTRIBUTE_ASSOCIATED_CLASS, None) + associated_class = cls._discover_associated_class(class_name, attrs, + inherited_associated_class) - if FACTORY_CLASS_DECLARATION in attrs: - own_associated_class = attrs.pop(FACTORY_CLASS_DECLARATION) - else: - factory_module = sys.modules[attrs['__module__']] - match = re.match(r'^(\w+)Factory$', class_name) - if match: - used_auto_discovery = True - associated_class_name = match.group(1) - try: - own_associated_class = getattr(factory_module, associated_class_name) - except AttributeError: - pass + # Remove the FACTORY_CLASS_DECLARATION attribute from attrs, if present. + attrs.pop(FACTORY_CLASS_DECLARATION, None) - if own_associated_class is None and inherited_associated_class is not None: - own_associated_class = inherited_associated_class + # If inheriting the factory from a parent, keep a link to it. + # This allows to use the sequence counters from the parents. + if associated_class == inherited_associated_class: attrs['_base_factory'] = base - if not own_associated_class: - if used_auto_discovery: - format_args = FACTORY_CLASS_DECLARATION, associated_class_name, class_name, factory_module - raise Factory.AssociatedClassError(FactoryMetaClass.ERROR_MESSAGE_AUTODISCOVERY.format(*format_args)) - else: - raise Factory.AssociatedClassError(FactoryMetaClass.ERROR_MESSAGE.format(FACTORY_CLASS_DECLARATION)) + # The CLASS_ATTRIBUTE_ASSOCIATED_CLASS must *not* be taken into account + # when parsing the declared attributes of the new class. + extra_attrs = {CLASS_ATTRIBUTE_ASSOCIATED_CLASS: associated_class} - extra_attrs = {CLASS_ATTRIBUTE_ASSOCIATED_CLASS: own_associated_class} return super(FactoryMetaClass, cls).__new__(cls, class_name, bases, attrs, extra_attrs=extra_attrs) # Factory base classes @@ -185,7 +255,7 @@ class BaseFactory(object): applicable; the current list of computed attributes is available to the currently processed object. """ - return AttributeBuilder(cls, extra).build(create) + return containers.AttributeBuilder(cls, extra).build(create) @classmethod def declarations(cls, extra_defs=None): @@ -201,7 +271,7 @@ class BaseFactory(object): @classmethod def stub(cls, **kwargs): - stub_object = StubObject() + stub_object = containers.StubObject() for name, value in cls.attributes(create=False, extra=kwargs).iteritems(): setattr(stub_object, name, value) return stub_object |