Refs #21231 -- Backport urllib.parse.parse_qsl() from Python 3.8.

tests/utils_tests/test_http.py

@@ -8,9 +8,10 @@ from django.utils.datastructures import MultiValueDict
 from django.utils.deprecation import RemovedInDjango40Warning
 from django.utils.http import (
     base36_to_int, escape_leading_slashes, http_date, int_to_base36,
-    is_safe_url, is_same_domain, parse_etags, parse_http_date, quote_etag,
-    url_has_allowed_host_and_scheme, urlencode, urlquote, urlquote_plus,
-    urlsafe_base64_decode, urlsafe_base64_encode, urlunquote, urlunquote_plus,
+    is_safe_url, is_same_domain, parse_etags, parse_http_date, parse_qsl,
+    quote_etag, url_has_allowed_host_and_scheme, urlencode, urlquote,
+    urlquote_plus, urlsafe_base64_decode, urlsafe_base64_encode, urlunquote,
+    urlunquote_plus,
 )
 
 
@@ -359,3 +360,68 @@ class EscapeLeadingSlashesTests(unittest.TestCase):
         for url, expected in tests:
             with self.subTest(url=url):
                 self.assertEqual(escape_leading_slashes(url), expected)
+
+
+# TODO: Remove when dropping support for PY37. Backport of unit tests for
+# urllib.parse.parse_qsl() from Python 3.8. Copyright (C) 2020 Python Software
+# Foundation (see LICENSE.python).
+class ParseQSLBackportTests(unittest.TestCase):
+    def test_parse_qsl(self):
+        tests = [
+            ('', []),
+            ('&', []),
+            ('&&', []),
+            ('=', [('', '')]),
+            ('=a', [('', 'a')]),
+            ('a', [('a', '')]),
+            ('a=', [('a', '')]),
+            ('&a=b', [('a', 'b')]),
+            ('a=a+b&b=b+c', [('a', 'a b'), ('b', 'b c')]),
+            ('a=1&a=2', [('a', '1'), ('a', '2')]),
+            (b'', []),
+            (b'&', []),
+            (b'&&', []),
+            (b'=', [(b'', b'')]),
+            (b'=a', [(b'', b'a')]),
+            (b'a', [(b'a', b'')]),
+            (b'a=', [(b'a', b'')]),
+            (b'&a=b', [(b'a', b'b')]),
+            (b'a=a+b&b=b+c', [(b'a', b'a b'), (b'b', b'b c')]),
+            (b'a=1&a=2', [(b'a', b'1'), (b'a', b'2')]),
+            (';', []),
+            (';;', []),
+            (';a=b', [('a', 'b')]),
+            ('a=a+b;b=b+c', [('a', 'a b'), ('b', 'b c')]),
+            ('a=1;a=2', [('a', '1'), ('a', '2')]),
+            (b';', []),
+            (b';;', []),
+            (b';a=b', [(b'a', b'b')]),
+            (b'a=a+b;b=b+c', [(b'a', b'a b'), (b'b', b'b c')]),
+            (b'a=1;a=2', [(b'a', b'1'), (b'a', b'2')]),
+        ]
+        for original, expected in tests:
+            with self.subTest(original):
+                result = parse_qsl(original, keep_blank_values=True)
+                self.assertEqual(result, expected, 'Error parsing %r' % original)
+                expect_without_blanks = [v for v in expected if len(v[1])]
+                result = parse_qsl(original, keep_blank_values=False)
+                self.assertEqual(result, expect_without_blanks, 'Error parsing %r' % original)
+
+    def test_parse_qsl_encoding(self):
+        result = parse_qsl('key=\u0141%E9', encoding='latin-1')
+        self.assertEqual(result, [('key', '\u0141\xE9')])
+        result = parse_qsl('key=\u0141%C3%A9', encoding='utf-8')
+        self.assertEqual(result, [('key', '\u0141\xE9')])
+        result = parse_qsl('key=\u0141%C3%A9', encoding='ascii')
+        self.assertEqual(result, [('key', '\u0141\ufffd\ufffd')])
+        result = parse_qsl('key=\u0141%E9-', encoding='ascii')
+        self.assertEqual(result, [('key', '\u0141\ufffd-')])
+        result = parse_qsl('key=\u0141%E9-', encoding='ascii', errors='ignore')
+        self.assertEqual(result, [('key', '\u0141-')])
+
+    def test_parse_qsl_max_num_fields(self):
+        with self.assertRaises(ValueError):
+            parse_qsl('&'.join(['a=a'] * 11), max_num_fields=10)
+        with self.assertRaises(ValueError):
+            parse_qsl(';'.join(['a=a'] * 11), max_num_fields=10)
+        parse_qsl('&'.join(['a=a'] * 10), max_num_fields=10)