diff --git a/tests/serializers/test_generator.py b/tests/serializers/test_generator.py
index 29e9eeb6b..89b6b0350 100644
--- a/tests/serializers/test_generator.py
+++ b/tests/serializers/test_generator.py
@@ -122,6 +122,8 @@ def test_include():
     ]
     with pytest.raises(ValueError, match='Negative indices cannot be used to exclude items on unsized iterables'):
         v.to_python(gen_ok('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'), include={-1: None, -2: None}, mode='json')
+    # Non-integer keys are ignored
+    v.to_python(gen_ok('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'), include={'__all__': None}, mode='json')
 
 
 def test_custom_serializer():