[FIX] survey: allow creating survey with no sections

Task#1958723

This commit fixes the survey form to allow creating, testing and sharing
surveys that don't have sections as long as they don't use the "page_per_section"
layout.

closes odoo/odoo#32159

Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>

addons/survey/controllers/main.py

@@ -72,7 +72,7 @@ class Survey(http.Controller):
         if (survey_sudo.is_closed or not survey_sudo.active) and (not answer_sudo or not answer_sudo.test_entry):
             return 'survey_closed'
 
-        if not survey_sudo.page_ids and survey_sudo.questions_layout != 'page_per_question':
+        if (not survey_sudo.page_ids and survey_sudo.questions_layout == 'page_per_section') or not survey_sudo.question_ids:
             return 'survey_void'
 
         if answer_sudo and answer_sudo.state == 'done':

addons/survey/models/survey_survey.py

@@ -278,7 +278,9 @@ class Survey(models.Model):
         """
         survey = user_input.survey_id
 
-        if survey.questions_layout == 'page_per_question' and survey.questions_selection == 'random':
+        if survey.questions_layout == 'one_page':
+            return (None, False)
+        elif survey.questions_layout == 'page_per_question' and survey.questions_selection == 'random':
             pages_or_questions = list(enumerate(
                 user_input.question_ids
             ))
@@ -451,7 +453,7 @@ class Survey(models.Model):
     def action_send_survey(self):
         """ Open a window to compose an email, pre-filled with the survey message """
         # Ensure that this survey has at least one page with at least one question.
-        if (not self.page_ids and self.questions_layout != 'page_per_question') or not self.question_ids:
+        if (not self.page_ids and self.questions_layout == 'page_per_section') or not self.question_ids:
             raise UserError(_('You cannot send an invitation for a survey that has no questions.'))
 
         if self.stage_id.closed: