Implement rich comparison operators for MinKey and MaxKey, PYTHON-604.

bson/max_key.py

@@ -18,17 +18,30 @@
 
 class MaxKey(object):
     """MongoDB internal MaxKey type.
+
+    .. versionchanged:: 2.7
+       ``MaxKey`` now implements comparison operators.
     """
 
     _type_marker = 127
 
     def __eq__(self, other):
-        if isinstance(other, MaxKey):
-            return True
-        return NotImplemented
+        return isinstance(other, MaxKey)
 
     def __ne__(self, other):
         return not self == other
 
+    def __le__(self, other):
+        return isinstance(other, MaxKey)
+    
+    def __lt__(self, dummy):
+        return False
+
+    def __ge__(self, dummy):
+        return True
+    
+    def __gt__(self, other):
+        return not isinstance(other, MaxKey)
+
     def __repr__(self):
         return "MaxKey()"

bson/min_key.py

@@ -18,17 +18,30 @@
 
 class MinKey(object):
     """MongoDB internal MinKey type.
+
+    .. versionchanged:: 2.7
+       ``MinKey`` now implements comparison operators.
     """
 
     _type_marker = 255
 
     def __eq__(self, other):
-        if isinstance(other, MinKey):
-            return True
-        return NotImplemented
+        return isinstance(other, MinKey)
 
     def __ne__(self, other):
         return not self == other
+    
+    def __le__(self, dummy):
+        return True
+    
+    def __lt__(self, other):
+        return not isinstance(other, MinKey)
+
+    def __ge__(self, other):
+        return isinstance(other, MinKey)
+    
+    def __gt__(self, dummy):
+        return False
 
     def __repr__(self):
-        return "MinKey()"
+        return "MinKey()"

test/test_bson.py

@@ -597,6 +597,49 @@ class TestBSON(unittest.TestCase):
                 self.fail('Traceback not captured')
         else:
             self.fail('InvalidBSON not raised')
+            
+    def test_minkey_maxkey_comparison(self):
+        # MinKey's <, <=, >, >=, !=, and ==.
+        self.assertTrue(MinKey() < None)
+        self.assertTrue(MinKey() < 1)
+        self.assertTrue(MinKey() <= 1)
+        self.assertTrue(MinKey() <= MinKey())
+        self.assertFalse(MinKey() > None)
+        self.assertFalse(MinKey() > 1)
+        self.assertFalse(MinKey() >= 1)
+        self.assertTrue(MinKey() >= MinKey())
+        self.assertTrue(MinKey() != 1)
+        self.assertFalse(MinKey() == 1)
+        self.assertTrue(MinKey() == MinKey())
+        
+        # MinKey compared to MaxKey.
+        self.assertTrue(MinKey() < MaxKey())
+        self.assertTrue(MinKey() <= MaxKey())
+        self.assertFalse(MinKey() > MaxKey())
+        self.assertFalse(MinKey() >= MaxKey())
+        self.assertTrue(MinKey() != MaxKey())
+        self.assertFalse(MinKey() == MaxKey())
+        
+        # MaxKey's <, <=, >, >=, !=, and ==.
+        self.assertFalse(MaxKey() < None)
+        self.assertFalse(MaxKey() < 1)
+        self.assertFalse(MaxKey() <= 1)
+        self.assertTrue(MaxKey() <= MaxKey())
+        self.assertTrue(MaxKey() > None)
+        self.assertTrue(MaxKey() > 1)
+        self.assertTrue(MaxKey() >= 1)
+        self.assertTrue(MaxKey() >= MaxKey())
+        self.assertTrue(MaxKey() != 1)
+        self.assertFalse(MaxKey() == 1)
+        self.assertTrue(MaxKey() == MaxKey())
+
+        # MaxKey compared to MinKey.
+        self.assertFalse(MaxKey() < MinKey())
+        self.assertFalse(MaxKey() <= MinKey())
+        self.assertTrue(MaxKey() > MinKey())
+        self.assertTrue(MaxKey() >= MinKey())
+        self.assertTrue(MaxKey() != MinKey())
+        self.assertFalse(MaxKey() == MinKey())
 
 
 if __name__ == "__main__":