1 files changed, 11 insertions, 3 deletions
diff --git a/Lib/test/test_posix.py b/Lib/test/test_posix.py
index 4ca6230..a6e2fed 100644
--- a/Lib/test/test_posix.py
+++ b/Lib/test/test_posix.py
@@ -581,17 +581,25 @@ class PosixTester(unittest.TestCase):
         self.assertRaises(OSError, posix.chdir, support.TESTFN)
 
     def test_listdir(self):
-        self.assertTrue(support.TESTFN in posix.listdir(os.curdir))
+        self.assertIn(support.TESTFN, posix.listdir(os.curdir))
 
     def test_listdir_default(self):
         # When listdir is called without argument,
         # it's the same as listdir(os.curdir).
-        self.assertTrue(support.TESTFN in posix.listdir())
+        self.assertIn(support.TESTFN, posix.listdir())
 
     def test_listdir_bytes(self):
         # When listdir is called with a bytes object,
         # the returned strings are of type bytes.
-        self.assertTrue(os.fsencode(support.TESTFN) in posix.listdir(b'.'))
+        self.assertIn(os.fsencode(support.TESTFN), posix.listdir(b'.'))
+
+    def test_listdir_bytes_like(self):
+        for cls in bytearray, memoryview:
+            with self.assertWarns(DeprecationWarning):
+                names = posix.listdir(cls(b'.'))
+            self.assertIn(os.fsencode(support.TESTFN), names)
+            for name in names:
+                self.assertIs(type(name), bytes)
 
     @unittest.skipUnless(posix.listdir in os.supports_fd,
                          "test needs fd support for posix.listdir()")