commit 1f11cf9521114447b3e32e2ac88f075ffaa37555
author Raymond Hettinger <rhettinger@users.noreply.github.com> Tue Jun 11 01:15:24 2019 -0700
committer GitHub <noreply@github.com> Tue Jun 11 01:15:24 2019 -0700
tree 5ae0cb114a30299b34a32db228d13017bf5e3bf5
parent 408a2ef1aceff1f4270c44552fa39ef93d9283e3

bpo-37219: Remove erroneous optimization for differencing an empty set (GH-13965)

Lib/test/test_set.py

diff --git a/Lib/test/test_set.py b/Lib/test/test_set.py
index bb1081f..e4766ab 100644
--- a/Lib/test/test_set.py
+++ b/Lib/test/test_set.py
@@ -895,6 +895,12 @@
             self.assertEqual(self.set, copy,
                              "%s != %s" % (self.set, copy))
 
+    def test_issue_37219(self):
+        with self.assertRaises(TypeError):
+            set().difference(123)
+        with self.assertRaises(TypeError):
+            set().difference_update(123)
+
 #------------------------------------------------------------------------------
 
 class TestBasicOpsEmpty(TestBasicOps, unittest.TestCase):