Move fake jar out to utils; add another version which remembers state.

src/persistent/tests/utils.py

+
+class ResettingJar(object):
+    """Testing stub for _p_jar attribute.
+    """
+    def __init__(self):
+        from persistent.cPickleCache import PickleCache # XXX stub it!
+        self.cache = PickleCache(self)
+        self.oid = 1
+        self.registered = {}
+
+    def add(self, obj):
+        import struct
+        obj._p_oid = struct.pack(">Q", self.oid)
+        self.oid += 1
+        obj._p_jar = self
+        self.cache[obj._p_oid] = obj
+
+    def close(self):
+        pass
+
+    # the following methods must be implemented to be a jar
+
+    def setklassstate(self):
+        # I don't know what this method does, but the pickle cache
+        # constructor calls it.
+        pass
+
+    def register(self, obj):
+        self.registered[obj] = 1
+
+    def setstate(self, obj):
+        # Trivial setstate() implementation that just re-initializes
+        # the object.  This isn't what setstate() is supposed to do,
+        # but it suffices for the tests.
+        obj.__class__.__init__(obj)
+
+class RememberingJar(object):
+    """Testing stub for _p_jar attribute.
+    """
+    def __init__(self):
+        from persistent.cPickleCache import PickleCache # XXX stub it!
+        self.cache = PickleCache(self)
+        self.oid = 1
+        self.registered = {}
+
+    def add(self, obj):
+        import struct
+        obj._p_oid = struct.pack(">Q", self.oid)
+        self.oid += 1
+        obj._p_jar = self
+        self.cache[obj._p_oid] = obj
+        # Remember object's state for later.
+        self.obj = obj
+        self.remembered = obj.__getstate__()
+
+    def close(self):
+        pass
+
+    def fake_commit(self):
+        self.remembered = self.obj.__getstate__()
+        self.obj._p_changed = 0
+
+    # the following methods must be implemented to be a jar
+
+    def setklassstate(self):
+        # I don't know what this method does, but the pickle cache
+        # constructor calls it.
+        pass
+
+    def register(self, obj):
+        self.registered[obj] = 1
+
+    def setstate(self, obj):
+        # Trivial setstate() implementation that resets the object's
+        # state as of the time it was added to the jar.
+        # This isn't what setstate() is supposed to do,
+        # but it suffices for the tests.
+        obj.__setstate__(self.remembered)
+