Consider normal and refund operations separately

Allow to explore all move lines

Spanish translation

Bugfixes

Show negative lines too

Show move type in account.move views

Tests include new fields

account_tax_balance/models/account_move.py

@@ -0,0 +1,42 @@
+# -*- coding: utf-8 -*-
+# © 2016 Antonio Espinosa <antonio.espinosa@tecnativa.com>
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from openerp import models, fields, api
+
+
+class AccountMove(models.Model):
+    _inherit = 'account.move'
+
+    move_type = fields.Selection(
+        string="Move type", selection=[
+            ('other', 'Other'),
+            ('liquidity', 'Liquidity'),
+            ('receivable', 'Receivable'),
+            ('receivable_refund', 'Receivable refund'),
+            ('payable', 'Payable'),
+            ('payable_refund', 'Payable refund'),
+        ], compute='_compute_move_type', store=True, readonly=True)
+
+    @api.multi
+    @api.depends('line_ids.account_id.internal_type', 'line_ids.balance')
+    def _compute_move_type(self):
+        def _balance_get(line_ids, internal_type):
+            return sum(line_ids.filtered(
+                lambda x: x.account_id.internal_type == internal_type).mapped(
+                    'balance'))
+
+        for move in self:
+            internal_types = move.line_ids.mapped('account_id.internal_type')
+            if 'liquidity' in internal_types:
+                move.move_type = 'liquidity'
+            elif 'payable' in internal_types:
+                balance = _balance_get(move.line_ids, 'payable')
+                move.move_type = (
+                    'payable' if balance < 0 else 'payable_refund')
+            elif 'receivable' in internal_types:
+                balance = _balance_get(move.line_ids, 'receivable')
+                move.move_type = (
+                    'receivable' if balance > 0 else 'receivable_refund')
+            else:
+                move.move_type = 'other'