[IMP] - Make recurrence mechanism on contract line

Make recurrence mechanism on contract line and some other refactoring

[FIX] - Keep contract_cron on account_analytic_account model

contract_cron defined with no_update option.
Changing it, will cause issue to past version installation.

[IMP] - Fix recurring_next_date default value

recurring_next_date should have start_date as default value in prepaid policy
and start_date + invoicing_interval if postpaid

[FIX] - Fix test check no journal

[IMP] - Return created invoices on recurring_create_invoice

[IMP] - Specific process to compute recurring_next_date for  monthly-last-day

fixes: #198

[ADD] - Add Post-migration script to bring recurrence info from contract to contract lines

[ADD] - Add search filter based on date_end and recurring_next_date

 - not_finished filter in contract search view
 - finished filter in contract search view
 - Next Invoice group by in contract search view

[ADD] - Add unit tests

- cases to compute first recurring next date
- contract recurring_next_date
- contract date_end

[IMP] - Improve Unit tests

contract/models/abstract_contract.py

@@ -0,0 +1,69 @@
+# Copyright 2004-2010 OpenERP SA
+# Copyright 2014 Angel Moya <angel.moya@domatix.com>
+# Copyright 2015 Pedro M. Baeza <pedro.baeza@tecnativa.com>
+# Copyright 2016-2018 Carlos Dauden <carlos.dauden@tecnativa.com>
+# Copyright 2016-2017 LasLabs Inc.
+# Copyright 2018 ACSONE SA/NV
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from odoo import api, models, fields
+
+
+class AbstractAccountAnalyticContract(models.AbstractModel):
+    _name = 'account.abstract.analytic.contract'
+    _description = 'Abstract Account Analytic Contract'
+
+    # These fields will not be synced to the contract
+    NO_SYNC = ['name', 'partner_id']
+
+    name = fields.Char(required=True)
+    # Needed for avoiding errors on several inherited behaviors
+    partner_id = fields.Many2one(
+        comodel_name="res.partner", string="Partner (always False)"
+    )
+    pricelist_id = fields.Many2one(
+        comodel_name='product.pricelist', string='Pricelist'
+    )
+    contract_type = fields.Selection(
+        selection=[('sale', 'Customer'), ('purchase', 'Supplier')],
+        default='sale',
+    )
+
+    journal_id = fields.Many2one(
+        'account.journal',
+        string='Journal',
+        default=lambda s: s._default_journal(),
+        domain="[('type', '=', contract_type),"
+        "('company_id', '=', company_id)]",
+    )
+    company_id = fields.Many2one(
+        'res.company',
+        string='Company',
+        required=True,
+        default=lambda self: self.env.user.company_id,
+    )
+
+    @api.onchange('contract_type')
+    def _onchange_contract_type(self):
+        if self.contract_type == 'purchase':
+            self.recurring_invoice_line_ids.filtered('automatic_price').update(
+                {'automatic_price': False}
+            )
+        self.journal_id = self.env['account.journal'].search(
+            [
+                ('type', '=', self.contract_type),
+                ('company_id', '=', self.company_id.id),
+            ],
+            limit=1,
+        )
+
+    @api.model
+    def _default_journal(self):
+        company_id = self.env.context.get(
+            'company_id', self.env.user.company_id.id
+        )
+        domain = [
+            ('type', '=', self.contract_type),
+            ('company_id', '=', company_id),
+        ]
+        return self.env['account.journal'].search(domain, limit=1)