[IMP] survey: add a stat button on survey to show the certified count

Purpose
=======

This commit adds a stat button on the survey form view showing the amount
of answers with the quizz_passed field set to True.
It allows to quickly see people that have been granted the certification.

On click, the stat button redirects to the answers list view with the "Quizz passed"
filter defaulted to True.

addons/survey/models/survey_survey.py

@@ -70,6 +70,7 @@ class Survey(models.Model):
     invite_count = fields.Integer("Invite", compute="_compute_survey_statistic")
     answer_count = fields.Integer("Started", compute="_compute_survey_statistic")
     answer_done_count = fields.Integer("Completed", compute="_compute_survey_statistic")
+    certified_count = fields.Integer("Certified", compute="_compute_certified_count")
 
     # scoring and certification fields
     scoring_type = fields.Selection([
@@ -119,6 +120,22 @@ class Survey(models.Model):
         for survey in self:
             survey.update(stat[survey.id])
 
+    @api.depends('certificate', 'user_input_ids.quizz_passed', 'user_input_ids.test_entry')
+    def _compute_certified_count(self):
+        stat = dict((cid, 0) for cid in self.ids)
+        certificate_surveys = self.filtered(lambda survey: survey.certificate)
+        if certificate_surveys:
+            read_group_res = self.env['survey.user_input'].read_group(
+                [('survey_id', 'in', certificate_surveys.ids), ('test_entry', '!=', True), ('quizz_passed', '=', True)],
+                [],
+                ['survey_id']
+            )
+            for item in read_group_res:
+                stat[item['survey_id'][0]] += item['survey_id_count']
+
+        for survey in self:
+            survey.certified_count = stat.get(survey.id, 0)
+
     def _compute_survey_url(self):
         """ Computes a public URL for the survey """
         base_url = self.env['ir.config_parameter'].sudo().get_param('web.base.url')
@@ -503,6 +520,16 @@ class Survey(models.Model):
         action['context'] = ctx
         return action
 
+    @api.multi
+    def action_survey_user_input_certified(self):
+        action_rec = self.env.ref('survey.action_survey_user_input_notest')
+        action = action_rec.read()[0]
+        ctx = dict(self.env.context)
+        ctx.update({'search_default_survey_id': self.ids[0],
+                    'search_default_quizz_passed': 1})
+        action['context'] = ctx
+        return action
+
     @api.multi
     def action_survey_user_input_invite(self):
         action_rec = self.env.ref('survey.action_survey_user_input_notest')

addons/survey/views/survey_survey_views.xml

@@ -24,6 +24,13 @@
                             icon="fa-envelope-o">
                             <field string="Invitations" name="invite_count" widget="statinfo"/>
                         </button>
+                        <button name="action_survey_user_input_certified"
+                            type="object"
+                            class="oe_stat_button"
+                            attrs="{'invisible': [('certificate', '=', False)]}"
+                            icon="fa-trophy">
+                            <field string="Certified" name="certified_count" widget="statinfo"/>
+                        </button>
                         <button name="action_survey_user_input_completed"
                             type="object"
                             class="oe_stat_button"