diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
index 177d80d..8be16c8 100644
--- a/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@ -2819,6 +2819,34 @@
             self.assertEqual(unicode_asucs4(s, len(s), 1), s+'\0')
             self.assertEqual(unicode_asucs4(s, len(s), 0), s+'\uffff')
 
+    # Test PyUnicode_AsUTF8()
+    @support.cpython_only
+    def test_asutf8(self):
+        from _testcapi import unicode_asutf8
+
+        bmp = '\u0100'
+        bmp2 = '\uffff'
+        nonbmp = chr(0x10ffff)
+
+        self.assertEqual(unicode_asutf8(bmp), b'\xc4\x80')
+        self.assertEqual(unicode_asutf8(bmp2), b'\xef\xbf\xbf')
+        self.assertEqual(unicode_asutf8(nonbmp), b'\xf4\x8f\xbf\xbf')
+        self.assertRaises(UnicodeEncodeError, unicode_asutf8, 'a\ud800b\udfffc')
+
+    # Test PyUnicode_AsUTF8AndSize()
+    @support.cpython_only
+    def test_asutf8andsize(self):
+        from _testcapi import unicode_asutf8andsize
+
+        bmp = '\u0100'
+        bmp2 = '\uffff'
+        nonbmp = chr(0x10ffff)
+
+        self.assertEqual(unicode_asutf8andsize(bmp), (b'\xc4\x80', 2))
+        self.assertEqual(unicode_asutf8andsize(bmp2), (b'\xef\xbf\xbf', 3))
+        self.assertEqual(unicode_asutf8andsize(nonbmp), (b'\xf4\x8f\xbf\xbf', 4))
+        self.assertRaises(UnicodeEncodeError, unicode_asutf8andsize, 'a\ud800b\udfffc')
+
     # Test PyUnicode_FindChar()
     @support.cpython_only
     def test_findchar(self):