Add a test for the abort with non-string candidates in calculate_suggestions.

Author: devdanzin

Lib/test/test_traceback.py

@@ -4072,6 +4072,17 @@ class A:
         actual = self.get_suggestion(A(), 'bluch')
         self.assertNotIn("blech", actual)
 
+    def test_suggestions_do_not_trigger_with_non_string_candidates(self):
+        class Parent:
+            def __dir__(self):
+                return [0, 'blech']
+
+        class WithNonStringAttrs(Parent):
+            blech = None
+
+        result = self.get_suggestion(WithNonStringAttrs(), "bluch")
+        self.assertNotIn("blech", result)
+
     def test_getattr_suggestions_no_args(self):
         class A:
             blech = None