bpo-31904: Correct error string in test_file_not_exists() for VxWorks (GH-25965)

The error string on VxWorks is "no such file or directory" for FileNotFoundError. That is, the 1st letter of the error string has lower case.

Author: pxinwr

Lib/test/test_py_compile.py

@@ -276,7 +276,7 @@ def test_file_not_exists(self):
         rc, stdout, stderr = self.pycompilecmd_failure(self.source_path, should_not_exists)
         self.assertEqual(rc, 1)
         self.assertEqual(stdout, b'')
-        self.assertIn(b'No such file or directory', stderr)
+        self.assertIn(b'no such file or directory', stderr.lower())
 
     def test_file_not_exists_with_quiet(self):
         should_not_exists = os.path.join(os.path.dirname(__file__), 'should_not_exists.py')

Misc/NEWS.d/next/Tests/2021-05-07-15-46-04.bpo-31904.8dk3la.rst

@@ -0,0 +1 @@
+Ignore error string case in test_file_not_exists().