1 files changed, 11 insertions, 1 deletions
diff --git a/tests/basics/builtin_hash.py b/tests/basics/builtin_hash.py
index d7615c3ec0..b6b2ad15cb 100644
--- a/tests/basics/builtin_hash.py
+++ b/tests/basics/builtin_hash.py
@@ -20,11 +20,12 @@ class A:
 print(hash(A()))
 print({A():1})
 
+# all user-classes have default __hash__
 class B:
     pass
 hash(B())
 
-
+# if __eq__ is defined then default __hash__ is not used
 class C:
     def __eq__(self, another):
         return True
@@ -32,3 +33,12 @@ try:
     hash(C())
 except TypeError:
     print("TypeError")
+
+# __hash__ must return an int
+class D:
+    def __hash__(self):
+        return None
+try:
+    hash(D())
+except TypeError:
+    print("TypeError")