Fixed comparison of Range with non-range objects

Fixes ticket psycopg#164.

Patch from Chris Withers on master.

NEWS

@@ -3,6 +3,8 @@ What's new in psycopg 2.5.1
 
 - Fixed build on Solaris 10 and 11 where the round() function is already
   declared (:ticket:`#146`).
+- Fixed comparison of `Range` with non-range objects (:ticket:`#164`).
+  Thanks to Chris Withers for the patch.
 
 
 What's new in psycopg 2.5

lib/_range.py

@@ -121,6 +121,8 @@ def __nonzero__(self):
         return self._bounds is not None
 
     def __eq__(self, other):
+        if not isinstance(other, Range):
+            return False
         return (self._lower == other._lower
             and self._upper == other._upper
             and self._bounds == other._bounds)

tests/test_types_extras.py

@@ -1212,6 +1212,19 @@ def assert_not_equal(r1, r2):
         assert_not_equal(Range(10, 20), Range(11, 20))
         assert_not_equal(Range(10, 20, '[)'), Range(10, 20, '[]'))
 
+    def test_eq_wrong_type(self):
+        from psycopg2.extras import Range
+        self.assertNotEqual(Range(10, 20), ())
+
+    def test_eq_subclass(self):
+        from psycopg2.extras import Range, NumericRange
+
+        class IntRange(NumericRange): pass
+        class PositiveIntRange(IntRange): pass
+
+        self.assertEqual(Range(10, 20), IntRange(10, 20))
+        self.assertEqual(PositiveIntRange(10, 20), IntRange(10, 20))
+
     def test_not_ordered(self):
         from psycopg2.extras import Range
         self.assertRaises(TypeError, lambda: Range(empty=True) < Range(0,4))