Issue #28295: Fixed the documentation and added tests for PyUnicode_AsUCS4().

Original patch by Xiang Zhang.

1 files changed, 17 insertions, 0 deletions

diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
index 9cb69d4862..c98cc14024 100644
--- a/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@ -2711,6 +2711,23 @@ class CAPITest(unittest.TestCase):
         self.assertEqual(size, nchar)
         self.assertEqual(wchar, nonbmp + '\0')
 
+    # Test PyUnicode_AsUCS4()
+    @support.cpython_only
+    def test_asucs4(self):
+        from _testcapi import unicode_asucs4
+        for s in ['abc', '\xa1\xa2', '\u4f60\u597d', 'a\U0001f600',
+                  'a\ud800b\udfffc', '\ud834\udd1e']:
+            l = len(s)
+            self.assertEqual(unicode_asucs4(s, l, 1), s+'\0')
+            self.assertEqual(unicode_asucs4(s, l, 0), s+'\uffff')
+            self.assertEqual(unicode_asucs4(s, l+1, 1), s+'\0\uffff')
+            self.assertEqual(unicode_asucs4(s, l+1, 0), s+'\0\uffff')
+            self.assertRaises(SystemError, unicode_asucs4, s, l-1, 1)
+            self.assertRaises(SystemError, unicode_asucs4, s, l-2, 0)
+            s = '\0'.join([s, s])
+            self.assertEqual(unicode_asucs4(s, len(s), 1), s+'\0')
+            self.assertEqual(unicode_asucs4(s, len(s), 0), s+'\uffff')
+
     @support.cpython_only
     def test_encode_decimal(self):
         from _testcapi import unicode_encodedecimal