hashcode should be kept constant after the object's creation

Author: zkytony

pomdp_py/framework/oopomdp.pyx

@@ -74,7 +74,6 @@ cdef class ObjectState(State):
         """__setitem__(self, attr, value)
         Sets the attribute `attr` to the given value."""
         self.attributes[attr] = value
-        self._hashcache = -1
 
     def __len__(self):
         return len(self.attributes)
@@ -109,10 +108,10 @@ cdef class OOState(State):
 
     @property
     def situation(self):
-        """situation(self)
+        """situation(selppf)
         This is a `frozenset` which can be used to identify
         the situation of this state since it supports hashing."""
-        return self._situation
+        return frozenset(self.object_states.items())
 
     def __str__(self):
         return '%s::[%s]' % (str(self.__class__.__name__),

tests/test_hashing_pickling.py

@@ -21,7 +21,8 @@ def test_hashing_pickling():
     objstate3 = objstate1.copy()
     assert hash(objstate3) == hash(objstate1)
     objstate3["color"] = "green"
-    assert hash(objstate3) != hash(objstate1)
+    # hashcode should be kept constant after the object's creation
+    assert hash(objstate3) == hash(objstate1)
     assert objstate3 != objstate1
 
     oos1 = pomdp_py.OOState({1:objstate1, 2:objstate2})