Issue #26560: Avoid potential ValueError in BaseHandler.start_response

Initial patch by Peter Inglesby.

1 files changed, 21 insertions, 0 deletions

diff --git a/Lib/test/test_wsgiref.py b/Lib/test/test_wsgiref.py
index 8cca595..3f800ef 100644
--- a/Lib/test/test_wsgiref.py
+++ b/Lib/test/test_wsgiref.py
@@ -166,6 +166,27 @@ class IntegrationTests(TestCase):
             " be of type list: <class 'tuple'>"
         )
 
+    def test_status_validation_errors(self):
+        def create_bad_app(status):
+            def bad_app(environ, start_response):
+                start_response(status, [("Content-Type", "text/plain; charset=utf-8")])
+                return [b"Hello, world!"]
+            return bad_app
+
+        tests = [
+            ('200', 'AssertionError: Status must be at least 4 characters'),
+            ('20X OK', 'AssertionError: Status message must begin w/3-digit code'),
+            ('200OK', 'AssertionError: Status message must have a space after code'),
+        ]
+
+        for status, exc_message in tests:
+            with self.subTest(status=status):
+                out, err = run_amock(create_bad_app(status))
+                self.assertTrue(out.endswith(
+                    b"A server error occurred.  Please contact the administrator."
+                ))
+                self.assertEqual(err.splitlines()[-2], exc_message)
+
     def test_wsgi_input(self):
         def bad_app(e,s):
             e["wsgi.input"].read()