Coverage for local/lib/python2.7/site-packages/sage/misc/nested_class_test.py : 100%

""" 

Test for nested class Parent 

This file contains a discussion, examples, and tests about nested 

classes and parents. It is kept in a separate file to avoid import 

loops. 

EXAMPLES: 

Currently pickling fails for parents using nested classes (typically 

for categories), but deriving only from Parent:: 

sage: from sage.misc.nested_class_test import TestParent1, TestParent2, TestParent3, TestParent4 

sage: P = TestParent1() 

sage: TestSuite(P).run() 

Failure ... 

The following tests failed: _test_elements, _test_pickling 

They actually need to be in the NestedClassMetaclass. However, due to 

a technical detail, this is currently not directly supported:: 

sage: P = TestParent2() 

Traceback (most recent call last): 

... 

TypeError: metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases 

sage: TestSuite(P).run() # not tested 

Instead, the easiest is to inherit from UniqueRepresentation, which is 

what you want to do anyway most of the time:: 

sage: P = TestParent3() 

sage: TestSuite(P).run() 

This is what all Sage's parents using categories currently do. An 

alternative is to use ClasscallMetaclass as metaclass:: 

sage: P = TestParent4() 

sage: TestSuite(P).run() 

""" 

#***************************************************************************** 

# Copyright (C) 2009 Nicolas M. Thiery <nthiery at users.sf.net> 

# 

# Distributed under the terms of the GNU General Public License (GPL) 

# http://www.gnu.org/licenses/ 

#****************************************************************************** 

from __future__ import print_function, absolute_import 

from six import add_metaclass 

__all__ = [] # Don't document any parents 

from sage.structure.parent import Parent 

from sage.structure.element_wrapper import ElementWrapper 

from sage.structure.unique_representation import UniqueRepresentation 

from sage.misc.classcall_metaclass import ClasscallMetaclass 

from sage.misc.nested_class import NestedClassMetaclass 

class TestParent1(Parent): 

def __init__(self): 

""" 

EXAMPLES:: 

sage: sage.misc.nested_class_test.TestParent1() 

<sage.misc.nested_class_test.TestParent1_with_category object at ...> 

""" 

from sage.categories.all import Sets 

Parent.__init__(self, category = Sets()) 

class Element(ElementWrapper): 

pass 

@add_metaclass(NestedClassMetaclass) 

class TestParent2(Parent): 

def __init__(self): 

""" 

EXAMPLES:: 

sage: sage.misc.nested_class_test.TestParent2() 

Traceback (most recent call last): 

TypeError: metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases 

""" 

from sage.categories.all import Sets 

Parent.__init__(self, category = Sets()) 

class Element(ElementWrapper): 

pass 

class TestParent3(UniqueRepresentation, Parent): 

def __init__(self): 

""" 

EXAMPLES:: 

sage: sage.misc.nested_class_test.TestParent3() 

<sage.misc.nested_class_test.TestParent3_with_category object at ...> 

""" 

from sage.categories.all import Sets 

Parent.__init__(self, category = Sets()) 

class Element(ElementWrapper): 

pass 

@add_metaclass(ClasscallMetaclass) 

class TestParent4(Parent): 

def __init__(self): 

""" 

EXAMPLES:: 

sage: sage.misc.nested_class_test.TestParent4() 

<sage.misc.nested_class_test.TestParent4_with_category object at ...> 

""" 

from sage.categories.all import Sets 

Parent.__init__(self, category = Sets()) 

def __eq__(self, other): 

""" 

EXAMPLES:: 

sage: from sage.misc.nested_class_test import TestParent4 

sage: TestParent4() == TestParent4() 

True 

""" 

return self.__class__ == other.__class__ 

def __ne__(self, other): 

""" 

EXAMPLES:: 

sage: from sage.misc.nested_class_test import TestParent4 

sage: TestParent4() != TestParent4() 

False 

""" 

return self.__class__ != other.__class__ 

class Element(ElementWrapper): 

pass 

# Class for tests: 

class B(object): 

""" 

A normal external class. 

""" 

pass 

class ABB(object): 

class B(object): 

""" 

This class is broken and can't be pickled. 

A warning is emmited during compilation. 

""" 

pass 

class ABL(object): 

""" 

There is no problem here. 

""" 

B=B 

class ALB(object): 

""" 

There is a nested class just below. Which can't be properly sphinxed. 

""" 

class C(object): 

""" 

Internal C class. 

Thanks to the links below this class is pickled ok. 

But it is sphixed wrong: It is typeset as a link to an outer class. 

""" 

pass 

C = ALB.C 

@add_metaclass(NestedClassMetaclass) 

class ABBMeta(object): 

class B(object): 

""" 

B interne 

""" 

pass 

@add_metaclass(NestedClassMetaclass) 

class ABLMeta(object): 

B = B 

@add_metaclass(NestedClassMetaclass) 

class ALBMeta(object): 

""" 

There is a nested class just below which is properly sphinxed. 

""" 

class CMeta(object): 

""" 

B interne 

""" 

pass 

CMeta = ALBMeta.CMeta 

class TestNestedParent(UniqueRepresentation, Parent): 

""" 

This is a dummy for testing source inspection of nested classes. 

EXAMPLES:: 

sage: from sage.misc.nested_class_test import TestNestedParent 

sage: from sage.misc.sageinspect import sage_getsource 

sage: P = TestNestedParent() 

sage: E = P.element_class 

sage: E.__bases__ 

(<class sage.misc.nested_class_test.TestNestedParent.Element at ...>, 

<class 'sage.categories.sets_cat.Sets.element_class'>) 

sage: print(sage_getsource(E)) 

class Element: 

"This is a dummy element class" 

pass 

""" 

class Element: 

"This is a dummy element class" 

pass