Add tests that quoted local parts are unquoted in the returned normalized address where possible

Author: JoshData

README.md

@@ -12,8 +12,8 @@ necessarily for composing an email message, see below).
 
 Key features:
 
-* Checks that an email address has the correct syntax --- good for
-  registration/login forms or other uses related to identifying users.
+* Checks that an email address has the correct syntax --- great for
+  email-based registration/login forms or validing data.
 * Gives friendly English error messages when validation fails that you
   can display to end-users.
 * Checks deliverability (optional): Does the domain name resolve?

tests/test_syntax.py

@@ -68,15 +68,41 @@
                 ascii_email='jeff@xn--fiqq24b10vi0d.tw',
             ),
         ),
+        (
+            '"quoted local part"@example.org',
+            ValidatedEmail(
+                local_part='"quoted local part"',
+                ascii_local_part='"quoted local part"',
+                smtputf8=False,
+                ascii_domain='example.org',
+                domain='example.org',
+                normalized='"quoted local part"@example.org',
+                ascii_email='"quoted local part"@example.org'
+            ),
+        ),
+        (
+            '"de-quoted.local.part"@example.org',
+            ValidatedEmail(
+                local_part='de-quoted.local.part',
+                ascii_local_part='de-quoted.local.part',
+                smtputf8=False,
+                ascii_domain='example.org',
+                domain='example.org',
+                normalized='de-quoted.local.part@example.org',
+                ascii_email='de-quoted.local.part@example.org'
+            ),
+        ),
     ],
 )
 def test_email_valid(email_input, output):
     # These addresses do not require SMTPUTF8. See test_email_valid_intl_local_part
     # for addresses that are valid but require SMTPUTF8. Check that it passes with
     # allow_smtput8 both on and off.
-    emailinfo = validate_email(email_input, check_deliverability=False, allow_smtputf8=False)
+    emailinfo = validate_email(email_input, check_deliverability=False, allow_smtputf8=False,
+                               allow_quoted_local=True)
     assert emailinfo == output
-    assert validate_email(email_input, check_deliverability=False, allow_smtputf8=True) == output
+    assert validate_email(email_input, check_deliverability=False, allow_smtputf8=True,
+                          allow_quoted_local=True) == output
 
     # Check that the old `email` attribute to access the normalized form still works
     # if the DeprecationWarning is suppressed.