[ZPatterns] Unit Testing ZPatterns Apps

[Roch'e Compaan]

We have quite a number of apps running on ZPatterns 0.4.3 and Zope 2.3.
All of the apps TTW and uses ZClasses.

I have tried to set up some unit tests using ZUnit 0.1.  I've managed
to call simple methods that report on the number of items in a specialist
and don't do any serious processing.

When I tried to test instance creation it failed with the following error:

Traceback (innermost last):
  File
"/usr/local/zope/2-3-2/lib/python/Products/PMTests/tests/ErvenTests.py",
line 38, in test_addAllotment
    Allotments.addInstance(REQUEST)
  File "/usr/local/zope/2-3-1/lib/python/Shared/DC/Scripts/Bindings.py",
line 324, in __call__
  File "/usr/local/zope/2-3-1/lib/python/Shared/DC/Scripts/Bindings.py",
line 354, in _bindAndExec
  File
"/usr/local/zope/2-3-2/lib/python/Products/PythonScripts/PythonScript.py",
line 336, in _exec
    result = apply(f, args, kw)
  File "Script (Python)", line 20, in addInstance
  File "/home/httpd/zope/Products/ZPatterns/Specialists.py", line 40, in
newItem
    return self.rackList[0].__of__(self).newItem(key)
  File "/home/httpd/zope/Products/ZPatterns/Rack.py", line 73, in newItem
    return self.createItem(key)
  File "/home/httpd/zope/Products/ZPatterns/Rack.py", line 128, in
createItem
    item = self.getItem(key)
  File "/home/httpd/zope/Products/ZPatterns/Rack.py", line 59, in getItem
    item = self.retrieveItem(key)
  File "/home/httpd/zope/Products/ZPatterns/Rack.py", line 97, in
retrieveItem
    if hasattr(item.aq_base, a):
  File "/home/httpd/zope/Products/ZPatterns/DataSkins.py", line 218, in
__get_attr__
    self = self._canonicalForm()
  File "/home/httpd/zope/Products/ZPatterns/DataSkins.py", line 240, in
_canonicalForm
    self.__dict__['_v_parent']
KeyError: _v_parent

What might cause this?  Is there anything specifically that one should
do in the set up of the test.  Has anybody been succesful in writing unit
tests for ZPatterns apps?

Roché