[FIX] partner_email_unique: duplicating partner sets empty email

partner_email_unique/models/res_partner.py

@@ -3,7 +3,7 @@
 #   Robin Keunen <robin@coopiteasy.be>
 # License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl.html).
 
-from openerp import models, api, _
+from openerp import models, api, _, fields
 from openerp.exceptions import ValidationError
 from openerp.tools import config
 
@@ -11,6 +11,8 @@ from openerp.tools import config
 class ResPartner(models.Model):
     _inherit = "res.partner"
 
+    email = fields.Char(copy=False)
+
     @api.multi
     @api.constrains('email')
     def _check_email(self):

partner_email_unique/tests/test_res_partner_email.py

@@ -37,3 +37,6 @@ class TestResPartnerEmailUnique(common.SavepointCase):
         # Empty email addresses don't raise
         self.partner1.email = False
         self.partner2.email = False
+
+    def test_copy_does_not_raise_duplicate_email_error(self):
+        self.partner1.copy()