Type check when comparing nodes

parsimonious/nodes.py

@@ -90,8 +90,10 @@ def __str__(self):
 
     def __eq__(self, other):
         """Support by-value deep comparison with other nodes for testing."""
-        return (other is not None and
-                self.expr_name == other.expr_name and
+        if not isinstance(other, Node):
+            return NotImplemented
+
+        return (self.expr_name == other.expr_name and
                 self.full_text == other.full_text and
                 self.start == other.start and
                 self.end == other.end and

parsimonious/tests/test_nodes.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 from nose import SkipTest
-from nose.tools import eq_, assert_raises
+from nose.tools import eq_, ok_, assert_raises
 
 from parsimonious import Grammar, NodeVisitor, VisitationError, rule
 from parsimonious.nodes import Node
@@ -142,3 +142,9 @@ def visit_greeting(self, thing, visited_children):
             raise PrimalScream('This should percolate up!')
 
     assert_raises(PrimalScream, Screamer().parse, 'howdy')
+
+
+def test_node_inequality():
+    node = Node('text', 'o hai', 0, 5)
+    ok_(node != 5)
+    ok_(node != None)