diff --git a/account_tax_balance/README.rst b/account_tax_balance/README.rst
index 8b9b2905..c5cfc281 100644
--- a/account_tax_balance/README.rst
+++ b/account_tax_balance/README.rst
@@ -42,6 +42,7 @@ Contributors
 ------------
 
 * Lorenzo Battistini <lorenzo.battistini@agilebg.com>
+* Giovanni Capalbo <giovanni@therp.nl>
 
 Maintainer
 ----------
diff --git a/account_tax_balance/tests/__init__.py b/account_tax_balance/tests/__init__.py
index 7094e61d..b1bcc511 100644
--- a/account_tax_balance/tests/__init__.py
+++ b/account_tax_balance/tests/__init__.py
@@ -1,3 +1,6 @@
-#Accounting tests extending AccountingTestCase
+# -*- coding: utf-8 -*-
+# © 2016 Lorenzo Battistini - Agile Business Group
+# © 2016 Giovanni Capalbo
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
 
-from . import test_account_tax_balance 
+from . import test_account_tax_balance
diff --git a/account_tax_balance/tests/test_account_tax_balance.py b/account_tax_balance/tests/test_account_tax_balance.py
index 9c7cd74a..edefd417 100644
--- a/account_tax_balance/tests/test_account_tax_balance.py
+++ b/account_tax_balance/tests/test_account_tax_balance.py
@@ -1,51 +1,33 @@
-#from openerp.addons.account.tests.account_test_users import AccountTestUsers
+# -*- coding: utf-8 -*-
+# © 2016 Lorenzo Battistini - Agile Business Group
+# © 2016 Giovanni Capalbo <giovanni@therp.nl>
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
 from openerp.tests.common import TransactionCase
-from openerp.tools import float_compare
- 
 
-class TestAccountTaxBalance(TransactionCase):
-    
-    def setUp(self): 
-        super(TestAccountTaxBalance, self).setUp() 
-        self.fixed_tax = self.tax_model.create({
-            'name': "Fixed tax",
-            'amount_type': 'fixed',
-            'amount': 10.0,
-            'sequence': 1,
-        })
-        self.fixed_tax_bis = self.tax_model.create({
-            'name': "Fixed tax bis",
-            'amount_type': 'fixed',
-            'amount': 15,
-            'sequence': 2,
-        })
-        self.percent_tax = self.tax_model.create({
-            'name': "Percent tax",
-            'amount_type': 'percent',
-            'amount': 10.0,
-            'sequence': 3,
-        })
-        self.bank_journal = self.env['account.journal'].search([('type', '=', 'bank'), ('company_id', '=', self.account_manager.company_id.id)])[0]
-        self.bank_account = self.bank_journal.default_debit_account_id
-        self.expense_account = self.env['account.account'].search([('user_type_id.type', '=', 'payable')], limit=1) #Should be done by onchange later
 
+class TestAccountTaxBalance(TransactionCase):
 
     def test_tax_balance(self):
-        company_id = self.env['res.users'].browse(self.env.uid).company_id.id
+        tax_account_id = self.env['account.account'].search(
+            [('name', '=', 'Tax Paid')], limit=1).id
         tax = self.env['account.tax'].create({
             'name': 'Tax 10.0',
             'amount': 10.0,
             'amount_type': 'fixed',
+            'account_id': tax_account_id,
         })
-        analytic_account = self.env['account.analytic.account'].create({
-            'name': 'test account',
-        })
-        invoice_account = self.env['account.account'].search([('user_type_id', '=', self.env.ref('account.data_account_type_receivable').id)], limit=1).id
-        invoice_line_account = self.env['account.account'].search([('user_type_id', '=', self.env.ref('account.data_account_type_expenses').id)], limit=1).id
+        invoice_account_id = self.env['account.account'].search(
+            [('user_type_id', '=', self.env.ref(
+                'account.data_account_type_receivable'
+            ).id)], limit=1).id
+        invoice_line_account_id = self.env['account.account'].search(
+            [('user_type_id', '=', self.env.ref(
+                'account.data_account_type_expenses').id)], limit=1).id
         invoice = self.env['account.invoice'].create({
             'partner_id': self.env.ref('base.res_partner_2').id,
-            'account_id': invoice_account,
-            'type': 'in_invoice',
+            'account_id': invoice_account_id,
+            'type': 'out_invoice',
         })
 
         self.env['account.invoice.line'].create({
@@ -54,19 +36,15 @@ class TestAccountTaxBalance(TransactionCase):
             'price_unit': 100.0,
             'invoice_id': invoice.id,
             'name': 'product that cost 100',
-            'account_id': invoice_line_account,
+            'account_id': invoice_line_account_id,
             'invoice_line_tax_ids': [(6, 0, [tax.id])],
-            'account_analytic_id': analytic_account.id,
         })
+        invoice._onchange_invoice_line_ids()
+        invoice._convert_to_write(invoice._cache)
+        self.assertEqual(invoice.state, 'draft')
 
-        # :     check that Initially supplier bill state is "Draft"
-        self.assertTrue((invoice.state == 'draft'), "Initially vendor bill state is Draft")
-
-        #change the state of invoice to open by clicking Validate button
+        # change the state of invoice to open by clicking Validate button
         invoice.signal_workflow('invoice_open')
-       
-        self.assertEquals(tax.base_balance, 100)
-        self.assertEquals(tax.balance, 10)
-        
-
 
+        self.assertEquals(tax.base_balance, -100)
+        self.assertEquals(tax.balance, -10)
diff --git a/account_tax_balance/wizard/open_tax_balances_view.xml b/account_tax_balance/wizard/open_tax_balances_view.xml
index fed17d33..f789ee88 100644
--- a/account_tax_balance/wizard/open_tax_balances_view.xml
+++ b/account_tax_balance/wizard/open_tax_balances_view.xml
@@ -37,4 +37,4 @@
             parent="account.menu_finance_reports"
             groups="account.group_account_user,account.group_account_manager"></menuitem>
     </data>
-</openerp>
\ No newline at end of file
+</openerp>