diff --git a/account_constraints/__init__.py b/account_constraints/__init__.py
index 9fd8f5806..ec1575354 100644
--- a/account_constraints/__init__.py
+++ b/account_constraints/__init__.py
@@ -18,3 +18,4 @@
 #
 ##############################################################################
 from . import model
+from . import tests
diff --git a/account_constraints/tests/__init__.py b/account_constraints/tests/__init__.py
new file mode 100644
index 000000000..d2b3476e4
--- /dev/null
+++ b/account_constraints/tests/__init__.py
@@ -0,0 +1,40 @@
+# -*- coding: utf-8 -*-
+#
+#
+#    Authors: Adrien Peiffer
+#    Copyright (c) 2014 Acsone SA/NV (http://www.acsone.eu)
+#    All Rights Reserved
+#
+#    WARNING: This program as such is intended to be used by professional
+#    programmers who take the whole responsibility of assessing all potential
+#    consequences resulting from its eventual inadequacies and bugs.
+#    End users who are looking for a ready-to-use solution with commercial
+#    guarantees and support are strongly advised to contact a Free Software
+#    Service Company.
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU Affero General Public License as
+#    published by the Free Software Foundation, either version 3 of the
+#    License, or (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU Affero General Public License for more details.
+#
+#    You should have received a copy of the GNU Affero General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+#
+
+from . import test_account_constraints
+
+fast_suite = [
+    test_account_constraints,
+]
+
+checks = [
+    test_account_constraints,
+]
+
+# vim:expandtab:smartindent:tabstop=4:softtabstop=4:shiftwidth=4:
diff --git a/account_constraints/tests/test_account_constraints.py b/account_constraints/tests/test_account_constraints.py
new file mode 100644
index 000000000..cfae38313
--- /dev/null
+++ b/account_constraints/tests/test_account_constraints.py
@@ -0,0 +1,96 @@
+# -*- coding: utf-8 -*-
+#
+#
+#    Authors: Adrien Peiffer
+#    Copyright (c) 2014 Acsone SA/NV (http://www.acsone.eu)
+#    All Rights Reserved
+#
+#    WARNING: This program as such is intended to be used by professional
+#    programmers who take the whole responsibility of assessing all potential
+#    consequences resulting from its eventual inadequacies and bugs.
+#    End users who are looking for a ready-to-use solution with commercial
+#    guarantees and support are strongly advised to contact a Free Software
+#    Service Company.
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU Affero General Public License as
+#    published by the Free Software Foundation, either version 3 of the
+#    License, or (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU Affero General Public License for more details.
+#
+#    You should have received a copy of the GNU Affero General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+#
+
+import openerp.tests.common as common
+from openerp.osv import orm
+from datetime import datetime
+from openerp.tools import DEFAULT_SERVER_DATE_FORMAT
+from openerp import workflow
+
+DB = common.DB
+ADMIN_USER_ID = common.ADMIN_USER_ID
+
+
+def create_simple_invoice(self):
+    partner_id = self.ref('base.res_partner_2')
+    product_id = self.ref('product.product_product_4')
+    today = datetime.now()
+    journal_id = self.ref('account.sales_journal')
+    date = today.strftime(DEFAULT_SERVER_DATE_FORMAT)
+    return self.env['account.invoice']\
+        .create({'partner_id': partner_id,
+                 'account_id':
+                 self.ref('account.a_recv'),
+                 'journal_id':
+                 journal_id,
+                 'date_invoice': date,
+                 'invoice_line': [(0, 0, {'name': 'test',
+                                          'account_id':
+                                          self.ref('account.a_sale'),
+                                          'price_unit': 2000.00,
+                                          'quantity': 1,
+                                          'product_id': product_id,
+                                          }
+                                   )
+                                  ],
+                 })
+
+
+class TestAccountConstraints(common.TransactionCase):
+
+    def setUp(self):
+        super(TestAccountConstraints, self).setUp()
+
+    def test_draft_move_invoice(self):
+        invoice = create_simple_invoice(self)
+        workflow.trg_validate(self.uid, 'account.invoice', invoice.id,
+                              'invoice_open', self.cr)
+        move = invoice.move_id
+        move_lines = move.line_id
+        move.with_context({'from_parent_object': True})\
+            .write({'state': 'draft'})
+        self.assertRaises(orm.except_orm, move_lines.write, {'credit': 0.0})
+
+    def test_post_move_invoice_ref(self):
+        invoice = create_simple_invoice(self)
+        workflow.trg_validate(self.uid, 'account.invoice', invoice.id,
+                              'invoice_open', self.cr)
+        move_lines = invoice.move_id.line_id
+        # here, normally no exception is raised in standard code.
+        # It's just to verify if it's
+        # possible to modify ref field in a post account_move_line
+        move_lines.with_context({'from_parent_object': True})\
+            .write({'ref': 'test'})
+
+    def test_post_move_invoice(self):
+        invoice = create_simple_invoice(self)
+        workflow.trg_validate(self.uid, 'account.invoice', invoice.id,
+                              'invoice_open', self.cr)
+        move_lines = invoice.move_id.line_id
+        self.assertRaises(orm.except_orm, move_lines.write, {'ref': 'test'})