diff --git a/Lib/test/test_email/test_email.py b/Lib/test/test_email/test_email.py
index 54ffcdc544e8bb..a3ccbbbabfb328 100644
--- a/Lib/test/test_email/test_email.py
+++ b/Lib/test/test_email/test_email.py
@@ -2743,6 +2743,20 @@ def test_multipart_custom_policy(self):
         self.assertEqual(str(cm.exception),
                          'There may be at most 1 To headers in a message')
 
+
+# Test the NonMultipart class
+class TestNonMultipart(TestEmailBase):
+    def test_nonmultipart_is_not_multipart(self):
+        msg = MIMENonMultipart('text', 'plain')
+        self.assertFalse(msg.is_multipart())
+
+    def test_attach_raises_exception(self):
+        msg = Message()
+        msg['Subject'] = 'subpart 1'
+        r = MIMENonMultipart('text', 'plain')
+        self.assertRaises(errors.MultipartConversionError, r.attach, msg)
+
+
 # A general test of parser->model->generator idempotency.  IOW, read a message
 # in, parse it into a message object tree, then without touching the tree,
 # regenerate the plain text.  The original text and the transformed text
diff --git a/Misc/NEWS.d/next/Tests/2021-11-28-15-25-02.bpo-19460.lr0aWs.rst b/Misc/NEWS.d/next/Tests/2021-11-28-15-25-02.bpo-19460.lr0aWs.rst
new file mode 100644
index 00000000000000..e2d3d9526ecab9
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2021-11-28-15-25-02.bpo-19460.lr0aWs.rst
@@ -0,0 +1 @@
+Add new Test for ``Lib/email/mime/nonmultipart.py::MIMENonMultipart``.