diff --git a/addons/purchase/purchase.py b/addons/purchase/purchase.py
index 8e59741124a..3a768a4c218 100644
--- a/addons/purchase/purchase.py
+++ b/addons/purchase/purchase.py
@@ -179,7 +179,7 @@ class purchase_order(osv.osv):
         'order_line': fields.one2many('purchase.order.line', 'order_id', 'Order Lines', states={'approved':[('readonly',True)],'done':[('readonly',True)]}),
         'validator' : fields.many2one('res.users', 'Validated by', readonly=True),
         'notes': fields.text('Notes'),
-        'invoice_ids': fields.many2many('account.invoice', 'purchase_invoice_rel', 'purchase_id', 'invoice_id', 'Taxes', help="Invoices generated for a purchase order"),
+        'invoice_ids': fields.many2many('account.invoice', 'purchase_invoice_rel', 'purchase_id', 'invoice_id', 'Invoices', help="Invoices generated for a purchase order"),
         'picking_ids': fields.one2many('stock.picking', 'purchase_id', 'Picking List', readonly=True, help="This is the list of picking list that have been generated for this purchase"),
         'shipped':fields.boolean('Received', readonly=True, select=True, help="It indicates that a picking has been done"),
         'shipped_rate': fields.function(_shipped_rate, method=True, string='Received', type='float'),
diff --git a/addons/purchase/purchase_unit_test.xml b/addons/purchase/purchase_unit_test.xml
index 93c0e42fae2..b35e0626085 100644
--- a/addons/purchase/purchase_unit_test.xml
+++ b/addons/purchase/purchase_unit_test.xml
@@ -41,19 +41,19 @@
 
         <!-- Treat generated invoice -->
         <assert model="purchase.order" id="test_purchase_1" string="Test purchase has now a corresponding invoice" severity="fatal">
-            <test expr="bool(invoice_id)" />
+            <test expr="bool(invoice_ids)" />
         </assert>
 
         <assert model="purchase.order" id="test_purchase_1" string="Test purchase's invoice has the same amount and is currently a draft">
-            <test expr="invoice_id.state">draft</test>
+            <test expr="invoice_ids[0].state">draft</test>
         </assert>
 
         <workflow model="account.invoice" action="invoice_open">
-            <value model="purchase.order" eval="obj(ref('test_purchase_1')).invoice_id.id" />
+            <value model="purchase.order" eval="obj(ref('test_purchase_1')).invoice_ids[0].id" />
         </workflow>
 
         <function model="account.invoice" name="pay_and_reconcile">
-            <value model="purchase.order" eval="[obj(ref('test_purchase_1')).invoice_id.id]" />
+            <value model="purchase.order" eval="[obj(ref('test_purchase_1')).invoice_ids[0].id]" />
             <value eval="1164" />
             <value eval="ref('account.cash')"/>
             <value eval="ref('account.period_' + str(int(time.strftime('%m'))))" />
@@ -64,7 +64,7 @@
         </function>
 
         <assert model="purchase.order" id="test_purchase_1" string="Test purchase's invoice is now paid" severity="error">
-            <test expr="invoice_id.state">paid</test>
+            <test expr="invoice_ids[0].state">paid</test>
         </assert>
 
         <!-- Treat generated picking -->
diff --git a/addons/purchase/test/purchase_from_order.yml b/addons/purchase/test/purchase_from_order.yml
index 8c14611661c..454580baaf4 100644
--- a/addons/purchase/test/purchase_from_order.yml
+++ b/addons/purchase/test/purchase_from_order.yml
@@ -133,8 +133,8 @@
 -
   I check that Traceability moves are created.
 -
-  I check that an invoice_id field of Delivery&Invoices gets bind with the value.  
+  I check that an invoice_ids field of Delivery&Invoices gets bind with the value.  
 -
   !python {model: purchase.order}: |
     pur_id2=self.browse(cr, uid, ref("purchase_order_po0"))
-    assert(pur_id2.invoice_id)
+    assert(pur_id2.invoice_ids)
diff --git a/addons/purchase/test/purchase_from_picking.yml b/addons/purchase/test/purchase_from_picking.yml
index e68668f408d..357d865b9c9 100644
--- a/addons/purchase/test/purchase_from_picking.yml
+++ b/addons/purchase/test/purchase_from_picking.yml
@@ -139,8 +139,8 @@
       {'active_ids': pick_ids})
     self.create_invoice(cr, uid, [id], {"active_ids": pick_ids, "active_id": pick_ids[0]})
 -
-  I check that an invoice_id field of Delivery&Invoices gets bind with the value.
+  I check that an invoice_ids field of Delivery&Invoices gets bind with the value.
 -
   !python {model: purchase.order}: |
     pur_id2=self.browse(cr, uid, ref("purchase_order_po2"))
-    assert(pur_id2.invoice_id)
+    assert(pur_id2.invoice_ids)