Fix overloaded operators in eradate (#8)

eradate/eradate_module.py

@@ -118,14 +118,17 @@ def __gt__(self, other):
         return not self.__le__(other)
 
     def __eq__(self, other):
-        if other is not None:
+        if isinstance(other, EraDate):
             return self.__int__() == other.__int__()
         else:
-            return self.__int__() == other
+            return False
 
     def __ne__(self, other):
         return not self.__eq__(other)
 
+    def __hash__(self):
+        return hash((self.bc, self.year, self.month, self.day))
+
     def as_datetime(self):
         """
         Just a placeholder, for future development.

tests/test_eradate.py

@@ -62,3 +62,22 @@ def test_custom_date_class(self):
         self.assertTrue(date_bc_lower != None)
         self.assertTrue(date_bc_lower_js < date_bc_higher)
         self.assertTrue(date_bc_lower == date_bc_lower_js)
+
+    def test_hashing(self):
+        ed1 = EraDate(2016, 1, 2)
+        ed2 = EraDate(2016, 1, 2)
+        self.assertEqual(ed1, ed2)
+        self.assertEqual(hash(ed1), hash(ed2))
+
+    def test_comparison(self):
+        ed1 = EraDate(2016, 1, 1)
+        ed2 = EraDate(2016, 1, 2)
+        self.assertLess(ed1, ed2)
+        self.assertGreater(ed2, ed1)
+        self.assertLessEqual(ed1, ed2)
+        self.assertGreaterEqual(ed2, ed1)
+        self.assertNotEqual(ed1, ed2)
+        self.assertEqual(ed1, ed1)
+
+        self.assertNotEqual(ed1, 42)
+        self.assertNotEqual(ed1, 'wat')