Use newer doctest

tests.py

+##############################################################################
+#
+# Copyright (c) 2003 Zope Corporation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+"""Acquisition test cases (and useful examples)
+
+  Acquisition [1] is a mechanism that allows objects to obtain
+  attributes from their environment.  It is similar to inheritence,
+  except that, rather than traversing an inheritence hierarchy
+  to obtain attributes, a containment hierarchy is traversed.
+
+  The "ExtensionClass":ExtensionClass.html. release includes mix-in
+  extension base classes that can be used to add acquisition as a
+  feature to extension subclasses.  These mix-in classes use the
+  context-wrapping feature of ExtensionClasses to implement
+  acquisition. Consider the following example::
+
+    >>> import ExtensionClass, Acquisition
+
+    >>> class C(ExtensionClass.Base):
+    ...   color='red'
+
+    >>> class A(Acquisition.Implicit):
+    ...   def report(self):
+    ...     print self.color
+
+    >>> a = A()
+    >>> c = C()
+    >>> c.a = a
+
+    >>> c.a.report()
+    red
+
+    >>> d = C()
+    >>> d.color = 'green'
+    >>> d.a = a
+
+    >>> d.a.report()
+    green
+
+    >>> a.report() # raises an attribute error
+    Traceback (most recent call last):
+    ...
+    AttributeError: color
+
+  The class 'A' inherits acquisition behavior from
+  'Acquisition.Implicit'.  The object, 'a', "has" the color of
+  objects 'c' and 'd' when it is accessed through them, but it
+  has no color by itself.  The object 'a' obtains attributes
+  from it's environment, where it's environment is defined by
+  the access path used to reach 'a'.
+
+  Acquisition wrappers
+
+    When an object that supports acquisition is accessed through
+    an extension class instance, a special object, called an
+    acquisition wrapper, is returned.  In the example above, the
+    expression 'c.a' returns an acquisition wrapper that
+    contains references to both 'c' and 'a'.  It is this wrapper
+    that performs attribute lookup in 'c' when an attribute
+    cannot be found in 'a'.
+
+    Aquisition wrappers provide access to the wrapped objects
+    through the attributes 'aq_parent', 'aq_self', 'aq_base'.  
+    In the example above, the expressions::
+      
+       >>> c.a.aq_parent is c
+       1
+
+    and::
+
+       >>> c.a.aq_self is a
+       1
+
+    both evaluate to true, but the expression::
+
+       >>> c.a is a
+       0
+
+    evaluates to false, because the expression 'c.a' evaluates
+    to an acquisition wrapper around 'c' and 'a', not 'a' itself.
+
+    The attribute 'aq_base' is similar to 'aq_self'.  Wrappers may be
+    nested and 'aq_self' may be a wrapped object.  The 'aq_base'
+    attribute is the underlying object with all wrappers removed.
+
+  Acquisition Control
+
+    Two styles of acquisition are supported in the current
+    ExtensionClass release, implicit and explicit aquisition.
+  
+    Implicit acquisition
+    
+      Implicit acquisition is so named because it searches for
+      attributes from the environment automatically whenever an
+      attribute cannot be obtained directly from an object or
+      through inheritence.
+  
+      An attribute may be implicitly acquired if it's name does
+      not begin with an underscore, '_'.
+  
+      To support implicit acquisition, an object should inherit
+      from the mix-in class 'Acquisition.Implicit'.
+  
+    Explicit Acquisition
+  
+      When explicit acquisition is used, attributes are not
+      automatically obtained from the environment.  Instead, the
+      method 'aq_aquire' must be used, as in::
+  
+        print c.a.aq_acquire('color')
+  
+      To support explicit acquisition, an object should inherit
+      from the mix-in class 'Acquisition.Explicit'.
+
+    Controlled Acquisition
+
+      A class (or instance) can provide attribute by attribute control
+      over acquisition.  This is done by:
+
+      - subclassing from 'Acquisition.Explicit', and
+
+      - setting all attributes that should be acquired to the special
+        value: 'Acquisition.Acquired'.  Setting an attribute to this
+        value also allows inherited attributes to be overridden with
+        acquired ones.
+
+        For example, in::
+
+          >>> class E(Acquisition.Explicit):
+          ...    id = 1
+          ...    secret = 2
+          ...    color = Acquisition.Acquired
+          ...    __roles__ = Acquisition.Acquired
+
+        The *only* attributes that are automatically acquired from
+        containing objects are 'color', and '__roles__'.
+
+          >>> c = C()
+          >>> c.foo = 'foo'
+          >>> c.e = E()
+          >>> c.e.color
+          'red'
+          >>> c.e.foo
+          Traceback (most recent call last):
+          ...
+          AttributeError: foo
+
+        Note also that the '__roles__' attribute is acquired even
+        though it's name begins with an underscore:
+
+          >>> c.__roles__ = 'Manager', 'Member'
+          >>> c.e.__roles__
+          ('Manager', 'Member')
+
+        In fact, the special 'Acquisition.Acquired' value can be used
+        in 'Acquisition.Implicit' objects to implicitly acquire
+        selected objects that smell like private objects.
+
+          >>> class I(Acquisition.Implicit):
+          ...    __roles__ = Acquisition.Acquired
+
+          >>> c.x = C()
+          >>> c.x.__roles__
+          Traceback (most recent call last):
+          ...
+          AttributeError: __roles__
+
+          >>> c.x = I()
+          >>> c.x.__roles__
+          ('Manager', 'Member')
+
+    Filtered Acquisition
+
+      The acquisition method, 'aq_acquire', accepts two optional
+      arguments. The first of the additional arguments is a
+      "filtering" function that is used when considering whether to
+      acquire an object.  The second of the additional arguments is an
+      object that is passed as extra data when calling the filtering
+      function and which defaults to 'None'.
+
+      The filter function is called with five arguments:
+
+      - The object that the 'aq_acquire' method was called on,
+
+      - The object where an object was found,
+
+      - The name of the object, as passed to 'aq_acquire',
+
+      - The object found, and
+
+      - The extra data passed to 'aq_acquire'.
+
+      If the filter returns a true object that the object found is
+      returned, otherwise, the acquisition search continues.
+
+      For example, in::
+
+        >>> from Acquisition import Explicit
+        
+        >>> class HandyForTesting:
+        ...     def __init__(self, name): self.name=name
+        ...     def __str__(self):
+        ...       return "%s(%s)" % (self.name, self.__class__.__name__)
+        ...     __repr__=__str__
+        
+        >>> class E(Explicit, HandyForTesting):
+        ...     pass
+        
+        >>> class Nice(HandyForTesting):
+        ...     isNice=1
+        ...     def __str__(self):
+        ...        return HandyForTesting.__str__(self)+' and I am nice!'
+        ...     __repr__=__str__
+        
+        >>> a = E('a')
+        >>> a.b = E('b')
+        >>> a.b.c = E('c')
+        >>> a.p = Nice('spam')
+        >>> a.b.p = E('p')
+        
+        >>> def find_nice(self, ancestor, name, object, extra):
+        ...     return hasattr(object,'isNice') and object.isNice
+        
+        >>> print a.b.c.aq_acquire('p', find_nice)
+        spam(Nice) and I am nice!
+
+      The filtered acquisition in the last line skips over the first
+      attribute it finds with the name 'p', because the attribute
+      doesn't satisfy the condition given in the filter.
+
+  Acquisition and methods
+
+    Python methods of objects that support acquisition can use
+    acquired attributes as in the 'report' method of the first example
+    above.  When a Python method is called on an object that is
+    wrapped by an acquisition wrapper, the wrapper is passed to the
+    method as the first argument.  This rule also applies to
+    user-defined method types and to C methods defined in pure mix-in
+    classes.
+
+    Unfortunately, C methods defined in extension base classes that
+    define their own data structures, cannot use aquired attributes at
+    this time.  This is because wrapper objects do not conform to the
+    data structures expected by these methods.
+
+  Acquiring Acquiring objects
+
+    Consider the following example::
+
+      >>> from Acquisition import Implicit
+      
+      >>> class C(Implicit):
+      ...     def __init__(self, name): self.name=name
+      ...     def __str__(self):
+      ...         return "%s(%s)" % (self.name, self.__class__.__name__)
+      ...     __repr__=__str__
+      
+      >>> a = C("a")
+      >>> a.b = C("b")
+      >>> a.b.pref = "spam"
+      >>> a.b.c = C("c")
+      >>> a.b.c.color = "red"
+      >>> a.b.c.pref = "eggs"
+      >>> a.x = C("x")
+
+      >>> o = a.b.c.x
+
+    The expression 'o.color' might be expected to return '"red"'. In
+    earlier versions of ExtensionClass, however, this expression
+    failed.  Acquired acquiring objects did not acquire from the
+    environment they were accessed in, because objects were only
+    wrapped when they were first found, and were not rewrapped as they
+    were passed down the acquisition tree.
+
+    In the current release of ExtensionClass, the expression "o.color"
+    does indeed return '"red"'.
+
+      >>> o.color
+      'red'
+
+    When searching for an attribute in 'o', objects are searched in
+    the order 'x', 'a', 'b', 'c'. So, for example, the expression,
+    'o.pref' returns '"spam"', not '"eggs"'::
+
+      >>> o.pref
+      'spam'
+
+    In earlier releases of ExtensionClass, the attempt to get the
+    'pref' attribute from 'o' would have failed.
+
+    If desired, the current rules for looking up attributes in complex
+    expressions can best be understood through repeated application of
+    the '__of__' method:
+
+    'a.x' -- 'x.__of__(a)'
+
+    'a.b' -- 'b.__of__(a)'
+
+    'a.b.x' -- 'x.__of__(a).__of__(b.__of__(a))'
+
+    'a.b.c' -- 'c.__of__(b.__of__(a))'
+
+    'a.b.c.x' --
+        'x.__of__(a).__of__(b.__of__(a)).__of__(c.__of__(b.__of__(a)))'
+
+    and by keeping in mind that attribute lookup in a wrapper
+    is done by trying to lookup the attribute in the wrapped object
+    first and then in the parent object.  In the expressions above
+    involving the '__of__' method, lookup proceeds from left to right.
+
+    Note that heuristics are used to avoid most of the repeated
+    lookups. For example, in the expression: 'a.b.c.x.foo', the object
+    'a' is searched no more than once, even though it is wrapped three
+    times.
+
+.. [1] Gil, J., Lorenz, D., 
+   "Environmental Acquisition--A New Inheritance-Like Abstraction Mechanism",
+   http://www.bell-labs.com/people/cope/oopsla/Oopsla96TechnicalProgramAbstracts.html#GilLorenz, 
+   OOPSLA '96 Proceedings, ACM SIG-PLAN, October, 1996
+
+$Id$
+"""
+
+import ExtensionClass
+import Acquisition
+
+class I(Acquisition.Implicit):
+    def __init__(self, id):
+        self.id = id
+    def __repr__(self):
+        return self.id
+
+class E(Acquisition.Explicit):
+    def __init__(self, id):
+        self.id = id
+    def __repr__(self):
+        return self.id
+
+def test_unwrapped():
+    """
+    >>> c = I('unwrapped')
+    >>> show(c)
+    unwrapped
+
+    >>> c.aq_parent
+    Traceback (most recent call last):
+    ...
+    AttributeError: aq_parent
+
+    >>> Acquisition.aq_acquire(c, 'id')
+    'unwrapped'
+    >>> Acquisition.aq_acquire(c, 'x')
+    Traceback (most recent call last):
+    ...
+    AttributeError: x
+    
+    >>> Acquisition.aq_acquire(c, 'id',
+    ...  lambda searched, parent, name, ob, extra: extra)
+    Traceback (most recent call last):
+    ...
+    AttributeError: id
+    >>> Acquisition.aq_acquire(c, 'id',
+    ...        lambda searched, parent, name, ob, extra: extra,
+    ...        1)
+    'unwrapped'
+
+    >>> Acquisition.aq_base(c) is c
+    1
+
+    >>> Acquisition.aq_chain(c)
+    [unwrapped]
+
+    >>> Acquisition.aq_chain(c, 1)
+    [unwrapped]
+
+    >>> Acquisition.aq_get(c, 'id')
+    'unwrapped'
+
+    >>> Acquisition.aq_get(c, 'x')
+    Traceback (most recent call last):
+    ...
+    AttributeError: x
+    >>> Acquisition.aq_get(c, 'x', 'foo')
+    'foo'
+    >>> Acquisition.aq_get(c, 'x', 'foo', 1)
+    'foo'
+
+    >>> Acquisition.aq_inner(c) is c
+    1
+
+    >>> Acquisition.aq_parent(c)
+
+    >>> Acquisition.aq_self(c) is c
+    1
+
+    
+    
+    """
+
+def test_simple():
+    """
+    >>> a = I('a')
+    >>> a.y = 42
+    >>> a.b = I('b')
+    >>> a.b.c = I('c')
+    >>> show(a.b.c)
+    c
+    |
+    b
+    |
+    a
+
+    >>> show(a.b.c.aq_parent)
+    b
+    |
+    a
+
+    >>> show(a.b.c.aq_self)
+    c
+
+    >>> show(a.b.c.aq_base)
+    c
+
+    >>> show(a.b.c.aq_inner)
+    c
+    |
+    b
+    |
+    a
+
+    >>> a.b.c.y
+    42
+
+    >>> a.b.c.aq_chain
+    [c, b, a]
+
+    >>> a.b.c.aq_inContextOf(a)
+    1
+    >>> a.b.c.aq_inContextOf(a.b)
+    1
+    >>> a.b.c.aq_inContextOf(a.b.c)
+    1
+
+
+    >>> a.b.c.aq_acquire('y')
+    42
+
+    >>> a.b.c.aq_acquire('id')
+    'c'
+
+    >>> a.b.c.aq_acquire('x')
+    Traceback (most recent call last):
+    ...
+    AttributeError: x
+    
+    >>> a.b.c.aq_acquire('id',
+    ...  lambda searched, parent, name, ob, extra: extra)
+    Traceback (most recent call last):
+    ...
+    AttributeError: id
+
+    >>> Acquisition.aq_acquire(a.b.c, 'id',
+    ...        lambda searched, parent, name, ob, extra: extra,
+    ...        1)
+    'c'
+
+    >>> Acquisition.aq_acquire(a.b.c, 'id')
+    'c'
+
+    >>> Acquisition.aq_acquire(a.b.c, 'x')
+    Traceback (most recent call last):
+    ...
+    AttributeError: x
+
+    >>> Acquisition.aq_acquire(a.b.c, 'y')
+    42
+    
+    >>> Acquisition.aq_acquire(a.b.c, 'id',
+    ...  lambda searched, parent, name, ob, extra: extra)
+    Traceback (most recent call last):
+    ...
+    AttributeError: id
+
+    >>> Acquisition.aq_acquire(a.b.c, 'id',
+    ...        lambda searched, parent, name, ob, extra: extra,
+    ...        1)
+    'c'
+
+    >>> show(Acquisition.aq_base(a.b.c))
+    c
+
+    >>> Acquisition.aq_chain(a.b.c)
+    [c, b, a]
+
+    >>> Acquisition.aq_chain(a.b.c, 1)
+    [c, b, a]
+
+    >>> Acquisition.aq_get(a.b.c, 'id')
+    'c'
+
+    >>> Acquisition.aq_get(a.b.c, 'x')
+    Traceback (most recent call last):
+    ...
+    AttributeError: x
+    >>> Acquisition.aq_get(a.b.c, 'x', 'foo')
+    'foo'
+    >>> Acquisition.aq_get(a.b.c, 'x', 'foo', 1)
+    'foo'
+
+    >>> show(Acquisition.aq_inner(a.b.c))
+    c
+    |
+    b
+    |
+    a
+
+    >>> show(Acquisition.aq_parent(a.b.c))
+    b
+    |
+    a
+
+    >>> show(Acquisition.aq_self(a.b.c))
+    c
+
+    """
+
+def test__of__exception():
+    """
+    Wrapper_findattr did't check for an exception in a user defined
+    __of__ method before passing the result to the filter. In this
+    case the 'value' argument of the filter was NULL, which caused
+    a segfault when being accessed.
+
+    >>> class UserError(Exception):
+    ...     pass
+    ...
+    >>> class X(Acquisition.Implicit):
+    ...     def __of__(self, parent):
+    ...         if Acquisition.aq_base(parent) is not parent:
+    ...             raise UserError, 'ack'
+    ...         return X.inheritedAttribute('__of__')(self, parent)
+    ...
+    >>> a = I('a')
+    >>> a.b = I('b')
+    >>> a.b.x = X('x')
+    >>> Acquisition.aq_acquire(a.b, 'x',
+    ...     lambda self, object, name, value, extra: repr(value))
+    Traceback (most recent call last):
+    ...
+    UserError: ack
+
+    """
+
+def test_muliple():
+    r"""
+    >>> a = I('a')
+    >>> a.color = 'red'
+    >>> a.a1 = I('a1')
+    >>> a.a1.color = 'green'
+    >>> a.a1.a11 = I('a11')
+    >>> a.a2 = I('a2')
+    >>> a.a2.a21 = I('a21')
+    >>> show(a.a1.a11.a2.a21)
+    a21
+    |
+    (a2)
+    |  \
+    |   (a2)
+    |   |  \
+    |   |   a2
+    |   |   |
+    |   |   a
+    |   |
+    |   a1
+    |   |
+    |   a
+    |
+    a11
+    |
+    a1
+    |
+    a
+
+    >>> a.a1.a11.a2.a21.color
+    'red'
+
+    >>> show(a.a1.a11.a2.a21.aq_parent)
+    (a2)
+    |  \
+    |   (a2)
+    |   |  \
+    |   |   a2
+    |   |   |
+    |   |   a
+    |   |
+    |   a1
+    |   |
+    |   a
+    |
+    a11
+    |
+    a1
+    |
+    a
+
+    >>> show(a.a1.a11.a2.a21.aq_parent.aq_parent)
+    a11
+    |
+    a1
+    |
+    a
+
+    >>> show(a.a1.a11.a2.a21.aq_self)
+    a21
+
+    >>> show(a.a1.a11.a2.a21.aq_parent.aq_self)
+    (a2)
+    |  \
+    |   a2
+    |   |
+    |   a
+    |
+    a1
+    |
+    a
+
+    >>> show(a.a1.a11.a2.a21.aq_base)
+    a21
+
+    >>> show(a.a1.a11.a2.a21.aq_inner)
+    a21
+    |
+    (a2)
+    |  \
+    |   (a2)
+    |   |  \
+    |   |   a2
+    |   |   |
+    |   |   a
+    |   |
+    |   a1
+    |   |
+    |   a
+    |
+    a11
+    |
+    a1
+    |
+    a
+
+    >>> show(a.a1.a11.a2.a21.aq_inner.aq_parent.aq_inner)
+    a2
+    |
+    a
+
+    >>> show(a.a1.a11.a2.a21.aq_inner.aq_parent.aq_inner.aq_parent)
+    a
+    
+    >>> a.a1.a11.a2.a21.aq_chain
+    [a21, a2, a11, a1, a]
+    
+    >>> a.a1.a11.a2.a21.aq_inContextOf(a)
+    1
+    
+    >>> a.a1.a11.a2.a21.aq_inContextOf(a.a2)
+    1
+
+    >>> a.a1.a11.a2.a21.aq_inContextOf(a.a1)
+    0
+    
+    >>> a.a1.a11.a2.a21.aq_acquire('color')
+    'red'
+    >>> a.a1.a11.a2.a21.aq_acquire('id')
+    'a21'
+
+    >>> a.a1.a11.a2.a21.aq_acquire('color',
+    ...     lambda ob, parent, name, v, extra: extra)
+    Traceback (most recent call last):
+    ...
+    AttributeError: color
+
+    >>> a.a1.a11.a2.a21.aq_acquire('color',
+    ...     lambda ob, parent, name, v, extra: extra, 1)
+    'red'
+    
+    >>> a.a1.y = 42
+    >>> a.a1.a11.a2.a21.aq_acquire('y')
+    42
+
+    >>> a.a1.a11.a2.a21.aq_acquire('y', containment=1)
+    Traceback (most recent call last):
+    ...
+    AttributeError: y
+
+    Much of the same, but with methods:
+
+    >>> show(Acquisition.aq_parent(a.a1.a11.a2.a21))
+    (a2)
+    |  \
+    |   (a2)
+    |   |  \
+    |   |   a2
+    |   |   |
+    |   |   a
+    |   |
+    |   a1
+    |   |
+    |   a
+    |
+    a11
+    |
+    a1
+    |
+    a
+
+    >>> show(Acquisition.aq_parent(a.a1.a11.a2.a21.aq_parent))
+    a11
+    |
+    a1
+    |
+    a
+
+    >>> show(Acquisition.aq_self(a.a1.a11.a2.a21))
+    a21
+
+    >>> show(Acquisition.aq_self(a.a1.a11.a2.a21.aq_parent))
+    (a2)
+    |  \
+    |   a2
+    |   |
+    |   a
+    |
+    a1
+    |
+    a
+
+    >>> show(Acquisition.aq_base(a.a1.a11.a2.a21))
+    a21
+
+    >>> show(Acquisition.aq_inner(a.a1.a11.a2.a21))
+    a21
+    |
+    (a2)
+    |  \
+    |   (a2)
+    |   |  \
+    |   |   a2
+    |   |   |
+    |   |   a
+    |   |
+    |   a1
+    |   |
+    |   a
+    |
+    a11
+    |
+    a1
+    |
+    a
+
+    >>> show(Acquisition.aq_inner(a.a1.a11.a2.a21.aq_inner.aq_parent))
+    a2
+    |
+    a
+
+    >>> show(Acquisition.aq_parent(
+    ...       a.a1.a11.a2.a21.aq_inner.aq_parent.aq_inner))
+    a
+    
+    >>> Acquisition.aq_chain(a.a1.a11.a2.a21)
+    [a21, a2, a11, a1, a]
+    
+    >>> Acquisition.aq_chain(a.a1.a11.a2.a21, 1)
+    [a21, a2, a]
+    
+    >>> Acquisition.aq_acquire(a.a1.a11.a2.a21, 'color')
+    'red'
+    >>> Acquisition.aq_acquire(a.a1.a11.a2.a21, 'id')
+    'a21'
+
+    >>> Acquisition.aq_acquire(a.a1.a11.a2.a21, 'color',
+    ...     lambda ob, parent, name, v, extra: extra)
+    Traceback (most recent call last):
+    ...
+    AttributeError: color
+
+    >>> Acquisition.aq_acquire(a.a1.a11.a2.a21, 'color',
+    ...     lambda ob, parent, name, v, extra: extra, 1)
+    'red'
+    
+    >>> a.a1.y = 42
+    >>> Acquisition.aq_acquire(a.a1.a11.a2.a21, 'y')
+    42
+
+    >>> Acquisition.aq_acquire(a.a1.a11.a2.a21, 'y', containment=1)
+    Traceback (most recent call last):
+    ...
+    AttributeError: y
+
+
+    """
+    
+def test_pinball():
+    r"""
+    >>> a = I('a')
+    >>> a.a1 = I('a1')
+    >>> a.a1.a11 = I('a11')
+    >>> a.a1.a12 = I('a12')
+    >>> a.a2 = I('a2')
+    >>> a.a2.a21 = I('a21')
+    >>> a.a2.a22 = I('a22')
+    >>> show(a.a1.a11.a1.a12.a2.a21.a2.a22)
+    a22
+    |
+    (a2)
+    |  \
+    |   (a2)
+    |   |  \
+    |   |   a2
+    |   |   |
+    |   |   a
+    |   |
+    |   (a2)
+    |   |  \
+    |   |   (a2)
+    |   |   |  \
+    |   |   |   a2
+    |   |   |   |
+    |   |   |   a
+    |   |   |
+    |   |   (a1)
+    |   |   |  \
+    |   |   |   (a1)
+    |   |   |   |  \
+    |   |   |   |   a1
+    |   |   |   |   |
+    |   |   |   |   a
+    |   |   |   |
+    |   |   |   a1
+    |   |   |   |
+    |   |   |   a
+    |   |   |
+    |   |   a11
+    |   |   |
+    |   |   a1
+    |   |   |
+    |   |   a
+    |   |
+    |   a12
+    |   |
+    |   (a1)
+    |   |  \
+    |   |   (a1)
+    |   |   |  \
+    |   |   |   a1
+    |   |   |   |
+    |   |   |   a
+    |   |   |
+    |   |   a1
+    |   |   |
+    |   |   a
+    |   |
+    |   a11
+    |   |
+    |   a1
+    |   |
+    |   a
+    |
+    a21
+    |
+    (a2)
+    |  \
+    |   (a2)
+    |   |  \
+    |   |   a2
+    |   |   |
+    |   |   a
+    |   |
+    |   (a1)
+    |   |  \
+    |   |   (a1)
+    |   |   |  \
+    |   |   |   a1
+    |   |   |   |
+    |   |   |   a
+    |   |   |
+    |   |   a1
+    |   |   |
+    |   |   a
+    |   |
+    |   a11
+    |   |
+    |   a1
+    |   |
+    |   a
+    |
+    a12
+    |
+    (a1)
+    |  \
+    |   (a1)
+    |   |  \
+    |   |   a1
+    |   |   |
+    |   |   a
+    |   |
+    |   a1
+    |   |
+    |   a
+    |
+    a11
+    |
+    a1
+    |
+    a
+    
+    """
+
+def test_explicit():
+    """
+    >>> a = E('a')
+    >>> a.y = 42
+    >>> a.b = E('b')
+    >>> a.b.c = E('c')
+    >>> show(a.b.c)
+    c
+    |
+    b
+    |
+    a
+
+    >>> show(a.b.c.aq_parent)
+    b
+    |
+    a
+
+    >>> show(a.b.c.aq_self)
+    c
+
+    >>> show(a.b.c.aq_base)
+    c
+
+    >>> show(a.b.c.aq_inner)
+    c
+    |
+    b
+    |
+    a
+
+    >>> a.b.c.y
+    Traceback (most recent call last):
+    ...
+    AttributeError: y
+
+    >>> a.b.c.aq_chain
+    [c, b, a]
+
+    >>> a.b.c.aq_inContextOf(a)
+    1
+    >>> a.b.c.aq_inContextOf(a.b)
+    1
+    >>> a.b.c.aq_inContextOf(a.b.c)
+    1
+
+
+    >>> a.b.c.aq_acquire('y')
+    42
+
+    >>> a.b.c.aq_acquire('id')
+    'c'
+
+    >>> a.b.c.aq_acquire('x')
+    Traceback (most recent call last):
+    ...
+    AttributeError: x
+    
+    >>> a.b.c.aq_acquire('id',
+    ...  lambda searched, parent, name, ob, extra: extra)
+    Traceback (most recent call last):
+    ...
+    AttributeError: id
+
+    >>> Acquisition.aq_acquire(a.b.c, 'id',
+    ...        lambda searched, parent, name, ob, extra: extra,
+    ...        1)
+    'c'
+
+    >>> Acquisition.aq_acquire(a.b.c, 'id')
+    'c'
+
+    >>> Acquisition.aq_acquire(a.b.c, 'x')
+    Traceback (most recent call last):
+    ...
+    AttributeError: x
+
+    >>> Acquisition.aq_acquire(a.b.c, 'y')
+    42
+    
+    >>> Acquisition.aq_acquire(a.b.c, 'id',
+    ...  lambda searched, parent, name, ob, extra: extra)
+    Traceback (most recent call last):
+    ...
+    AttributeError: id
+
+    >>> Acquisition.aq_acquire(a.b.c, 'id',
+    ...        lambda searched, parent, name, ob, extra: extra,
+    ...        1)
+    'c'
+
+    >>> show(Acquisition.aq_base(a.b.c))
+    c
+
+    >>> Acquisition.aq_chain(a.b.c)
+    [c, b, a]
+
+    >>> Acquisition.aq_chain(a.b.c, 1)
+    [c, b, a]
+
+    >>> Acquisition.aq_get(a.b.c, 'id')
+    'c'
+
+    >>> Acquisition.aq_get(a.b.c, 'x')
+    Traceback (most recent call last):
+    ...
+    AttributeError: x
+
+    >>> Acquisition.aq_get(a.b.c, 'y')
+    42
+
+    >>> Acquisition.aq_get(a.b.c, 'x', 'foo')
+    'foo'
+    >>> Acquisition.aq_get(a.b.c, 'x', 'foo', 1)
+    'foo'
+
+    >>> show(Acquisition.aq_inner(a.b.c))
+    c
+    |
+    b
+    |
+    a
+
+    >>> show(Acquisition.aq_parent(a.b.c))
+    b
+    |
+    a
+
+    >>> show(Acquisition.aq_self(a.b.c))
+    c
+
+    """
+
+def test_mixed_explicit_and_explicit():
+    """
+    >>> a = I('a')
+    >>> a.y = 42
+    >>> a.b = E('b')
+    >>> a.b.z = 3
+    >>> a.b.c = I('c')
+    >>> show(a.b.c)
+    c
+    |
+    b
+    |
+    a
+
+    >>> show(a.b.c.aq_parent)
+    b
+    |
+    a
+
+    >>> show(a.b.c.aq_self)
+    c
+
+    >>> show(a.b.c.aq_base)
+    c
+
+    >>> show(a.b.c.aq_inner)
+    c
+    |
+    b
+    |
+    a
+
+    >>> a.b.c.y
+    42
+
+    >>> a.b.c.z
+    3
+
+    >>> a.b.c.aq_chain
+    [c, b, a]
+
+    >>> a.b.c.aq_inContextOf(a)
+    1
+    >>> a.b.c.aq_inContextOf(a.b)
+    1
+    >>> a.b.c.aq_inContextOf(a.b.c)
+    1
+
+    >>> a.b.c.aq_acquire('y')
+    42
+
+    >>> a.b.c.aq_acquire('z')
+    3
+
+    >>> a.b.c.aq_acquire('z', explicit=False)
+    3
+
+    >>> a.b.c.aq_acquire('id')
+    'c'
+
+    >>> a.b.c.aq_acquire('x')
+    Traceback (most recent call last):
+    ...
+    AttributeError: x
+    
+    >>> a.b.c.aq_acquire('id',
+    ...  lambda searched, parent, name, ob, extra: extra)
+    Traceback (most recent call last):
+    ...
+    AttributeError: id
+
+    >>> Acquisition.aq_acquire(a.b.c, 'id',
+    ...        lambda searched, parent, name, ob, extra: extra,
+    ...        1)
+    'c'
+
+    >>> Acquisition.aq_acquire(a.b.c, 'id')
+    'c'
+
+    >>> Acquisition.aq_acquire(a.b.c, 'x')
+    Traceback (most recent call last):
+    ...
+    AttributeError: x
+
+    >>> Acquisition.aq_acquire(a.b.c, 'y')
+    42
+    
+    >>> Acquisition.aq_acquire(a.b.c, 'id',
+    ...  lambda searched, parent, name, ob, extra: extra)
+    Traceback (most recent call last):
+    ...
+    AttributeError: id
+
+    >>> Acquisition.aq_acquire(a.b.c, 'id',
+    ...        lambda searched, parent, name, ob, extra: extra,
+    ...        1)
+    'c'
+
+    >>> show(Acquisition.aq_base(a.b.c))
+    c
+
+    >>> Acquisition.aq_chain(a.b.c)
+    [c, b, a]
+
+    >>> Acquisition.aq_chain(a.b.c, 1)
+    [c, b, a]
+
+    >>> Acquisition.aq_get(a.b.c, 'id')
+    'c'
+
+    >>> Acquisition.aq_get(a.b.c, 'x')
+    Traceback (most recent call last):
+    ...
+    AttributeError: x
+
+    >>> Acquisition.aq_get(a.b.c, 'y')
+    42
+
+    >>> Acquisition.aq_get(a.b.c, 'x', 'foo')
+    'foo'
+    >>> Acquisition.aq_get(a.b.c, 'x', 'foo', 1)
+    'foo'
+
+    >>> show(Acquisition.aq_inner(a.b.c))
+    c
+    |
+    b
+    |
+    a
+
+    >>> show(Acquisition.aq_parent(a.b.c))
+    b
+    |
+    a
+
+    >>> show(Acquisition.aq_self(a.b.c))
+    c
+
+    """
+
+
+def old_tests():
+    """    
+    >>> from ExtensionClass import Base
+    >>> import Acquisition
+
+    >>> class B(Base):
+    ...     color='red'
+
+    >>> class A(Acquisition.Implicit):
+    ...     def hi(self):
+    ...         print "%s()" % self.__class__.__name__, self.color
+
+    >>> b=B()
+    >>> b.a=A()
+    >>> b.a.hi()
+    A() red
+    >>> b.a.color='green'
+    >>> b.a.hi()
+    A() green
+    >>> try:
+    ...     A().hi()
+    ...     raise 'Program error', 'spam'
+    ... except AttributeError: pass
+    A()
+    
+       New test for wrapper comparisons.
+    
+    >>> foo = b.a
+    >>> bar = b.a
+    >>> foo == bar
+    1
+    >>> c = A()
+    >>> b.c = c
+    >>> b.c.d = c
+    >>> b.c.d == c
+    1
+    >>> b.c.d == b.c
+    1
+    >>> b.c == c
+    1
+
+
+    >>> def checkContext(self, o):
+    ...     # Python equivalent to aq_inContextOf
+    ...     from Acquisition import aq_base, aq_parent, aq_inner
+    ...     subob = self
+    ...     o = aq_base(o)
+    ...     while 1:
+    ...         if aq_base(subob) is o: return 1
+    ...         self = aq_inner(subob)
+    ...         if self is None: break
+    ...         subob = aq_parent(self)
+    ...         if subob is None: break
+
+
+    >>> checkContext(b.c, b)
+    1
+    >>> not checkContext(b.c, b.a)
+    1
+    
+    >>> b.a.aq_inContextOf(b)
+    1
+    >>> b.c.aq_inContextOf(b)
+    1
+    >>> b.c.d.aq_inContextOf(b)
+    1
+    >>> b.c.d.aq_inContextOf(c)
+    1
+    >>> b.c.d.aq_inContextOf(b.c)
+    1
+    >>> not b.c.aq_inContextOf(foo)
+    1
+    >>> not b.c.aq_inContextOf(b.a)
+    1
+    >>> not b.a.aq_inContextOf('somestring')
+    1
+    """
+
+def test_AqAlg():
+    """
+    >>> A=I('A')
+    >>> A.B=I('B')
+    >>> A.B.color='red'
+    >>> A.C=I('C')
+    >>> A.C.D=I('D')
+
+    >>> A
+    A
+    >>> Acquisition.aq_chain(A)
+    [A]
+    >>> Acquisition.aq_chain(A, 1)
+    [A]
+    >>> map(Acquisition.aq_base, Acquisition.aq_chain(A, 1))
+    [A]
+    >>> A.C
+    C
+    >>> Acquisition.aq_chain(A.C)
+    [C, A]
+    >>> Acquisition.aq_chain(A.C, 1)
+    [C, A]
+    >>> map(Acquisition.aq_base, Acquisition.aq_chain(A.C, 1))
+    [C, A]
+
+    >>> A.C.D
+    D
+    >>> Acquisition.aq_chain(A.C.D)
+    [D, C, A]
+    >>> Acquisition.aq_chain(A.C.D, 1)
+    [D, C, A]
+    >>> map(Acquisition.aq_base, Acquisition.aq_chain(A.C.D, 1))
+    [D, C, A]
+
+    >>> A.B.C
+    C
+    >>> Acquisition.aq_chain(A.B.C)
+    [C, B, A]
+    >>> Acquisition.aq_chain(A.B.C, 1)
+    [C, A]
+    >>> map(Acquisition.aq_base, Acquisition.aq_chain(A.B.C, 1))
+    [C, A]
+
+    >>> A.B.C.D
+    D
+    >>> Acquisition.aq_chain(A.B.C.D)
+    [D, C, B, A]
+    >>> Acquisition.aq_chain(A.B.C.D, 1)
+    [D, C, A]
+    >>> map(Acquisition.aq_base, Acquisition.aq_chain(A.B.C.D, 1))
+    [D, C, A]
+    
+
+    >>> A.B.C.D.color
+    'red'
+    >>> Acquisition.aq_get(A.B.C.D, "color", None)
+    'red'
+    >>> Acquisition.aq_get(A.B.C.D, "color", None, 1)
+    
+    """
+
+def test_explicit_acquisition():
+    """
+    >>> from ExtensionClass import Base
+    >>> import Acquisition
+
+    >>> class B(Base):
+    ...     color='red'
+
+    >>> class A(Acquisition.Explicit):
+    ...     def hi(self):
+    ...         print self.__class__.__name__, self.acquire('color')
+
+    >>> b=B()
+    >>> b.a=A()
+    >>> b.a.hi()
+    A red
+    >>> b.a.color='green'
+    >>> b.a.hi()
+    A green
+
+    >>> try:
+    ...     A().hi()
+    ...     raise 'Program error', 'spam'
+    ... except AttributeError: pass
+    A
+    
+    """
+
+def test_creating_wrappers_directly():
+    """
+    >>> from ExtensionClass import Base
+    >>> from Acquisition import ImplicitAcquisitionWrapper
+
+    >>> class B(Base):
+    ...     pass
+
+
+    >>> a = B()
+    >>> a.color = 'red'
+    >>> a.b = B()
+    >>> w = ImplicitAcquisitionWrapper(a.b, a)
+    >>> w.color
+    'red'
+
+    >>> w = ImplicitAcquisitionWrapper(a.b)
+    Traceback (most recent call last):
+    ...
+    TypeError: argument must be 2-item sequence, not B
+
+    We can reassign aq_parent
+
+    >>> x = B()
+    >>> x.color = 'green'
+    >>> w.aq_parent = x
+    >>> w.color
+    'green'
+
+    >>> w = ImplicitAcquisitionWrapper()
+    Traceback (most recent call last):
+    ...
+    TypeError: function takes at least one argument
+
+    """
+
+def test_cant_pickle_acquisition_wrappers_classic():
+    """
+    >>> import pickle
+
+    >>> class X:
+    ...     def __getstate__(self):
+    ...         return 1
+
+    We shouldn't be able to pickle wrappers:
+
+    >>> from Acquisition import ImplicitAcquisitionWrapper
+    >>> w = ImplicitAcquisitionWrapper(X(), X())
+    >>> pickle.dumps(w)
+    Traceback (most recent call last):
+    ...
+    TypeError: Can't pickle objects in acquisition wrappers.
+
+    But that's not enough. We need to defeat persistence as well. :)
+    This is tricky. We want to generate the error in __getstate__, not
+    in the attr access, as attribute errors are too-often hidden:
+
+    >>> getstate = w.__getstate__
+    >>> getstate()
+    Traceback (most recent call last):
+    ...
+    TypeError: Can't pickle objects in acquisition wrappers.
+
+    We shouldn't be able to pickle wrappers:
+
+    >>> from Acquisition import ExplicitAcquisitionWrapper
+    >>> w = ExplicitAcquisitionWrapper(X(), X())
+    >>> pickle.dumps(w)
+    Traceback (most recent call last):
+    ...
+    TypeError: Can't pickle objects in acquisition wrappers.
+
+    But that's not enough. We need to defeat persistence as well. :)
+    This is tricky. We want to generate the error in __getstate__, not
+    in the attr access, as attribute errors are too-often hidden:
+
+    >>> getstate = w.__getstate__
+    >>> getstate()
+    Traceback (most recent call last):
+    ...
+    TypeError: Can't pickle objects in acquisition wrappers.
+    """
+
+def test_cant_pickle_acquisition_wrappers_newstyle():
+    """
+    >>> import pickle
+
+    >>> class X(object):
+    ...     def __getstate__(self):
+    ...         return 1
+
+    We shouldn't be able to pickle wrappers:
+
+    >>> from Acquisition import ImplicitAcquisitionWrapper
+    >>> w = ImplicitAcquisitionWrapper(X(), X())
+    >>> pickle.dumps(w)
+    Traceback (most recent call last):
+    ...
+    TypeError: Can't pickle objects in acquisition wrappers.
+
+    But that's not enough. We need to defeat persistence as well. :)
+    This is tricky. We want to generate the error in __getstate__, not
+    in the attr access, as attribute errors are too-often hidden:
+
+    >>> getstate = w.__getstate__
+    >>> getstate()
+    Traceback (most recent call last):
+    ...
+    TypeError: Can't pickle objects in acquisition wrappers.
+
+    We shouldn't be able to pickle wrappers:
+
+    >>> from Acquisition import ExplicitAcquisitionWrapper
+    >>> w = ExplicitAcquisitionWrapper(X(), X())
+    >>> pickle.dumps(w)
+    Traceback (most recent call last):
+    ...
+    TypeError: Can't pickle objects in acquisition wrappers.
+
+    But that's not enough. We need to defeat persistence as well. :)
+    This is tricky. We want to generate the error in __getstate__, not
+    in the attr access, as attribute errors are too-often hidden:
+
+    >>> getstate = w.__getstate__
+    >>> getstate()
+    Traceback (most recent call last):
+    ...
+    TypeError: Can't pickle objects in acquisition wrappers.
+    """
+
+def show(x):
+    print showaq(x).strip()
+    
+def showaq(m_self, indent=''):
+    rval = ''
+    obj = m_self
+    base = getattr(obj, 'aq_base', obj)
+    try: id = base.id
+    except: id = str(base)
+    try: id = id()
+    except: pass
+
+    if hasattr(obj, 'aq_self'):
+        if hasattr(obj.aq_self, 'aq_self'):
+            rval = rval + indent + "(" + id + ")\n"
+            rval = rval + indent + "|  \\\n"
+            rval = rval + showaq(obj.aq_self, '|   ' + indent)
+            rval = rval + indent + "|\n"
+            rval = rval + showaq(obj.aq_parent, indent)
+        elif hasattr(obj, 'aq_parent'):
+            rval = rval + indent + id + "\n"
+            rval = rval + indent + "|\n"
+            rval = rval + showaq(obj.aq_parent, indent)
+    else:
+        rval = rval + indent + id + "\n"
+    return rval
+
+    
+
+import unittest
+from zope.testing.doctest import DocTestSuite
+
+def test_suite():
+    return unittest.TestSuite((
+        DocTestSuite(),
+        ))
+
+if __name__ == '__main__': unittest.main()