[IMP] mail: add tool methods to manage activities directly from the mixin

This commit adds tools methods related to activities in the mail.activity
mixin. It gives to models inheriting from the activity mixin an easy-to-use
API to schedule, unlink or mark activities as done. Purpose of those methods
is to avoid having people manually managing activities in the code to hide
the technical details of the activities model, notably access rights
or activity types.

A field is added on activity model to indicate they have been generated
automatically. This way when rescheduling or unlinking based on some
specific activity types we do not change user-created activities.

Those methods include scheduling activities, changing their dates, marking
them as done or unlinking them. Future commits will use those methods
in various addons to automatically generate activities based on workflow
we want to implement.

This commit also adds tests for the newly added code. Future commits should
probably have a look at activity security and add some tests cases to check
it is correctly taken into account. It is considered a bit out of scope for
this task.

Thanks to @jem-odoo for its in-depth review of this commit. Well thanks for
other commits also.

1 files changed, 1 insertions, 0 deletions

diff --git a/addons/test_mail/__manifest__.py b/addons/test_mail/__manifest__.py
index 51d9cc7fe42..40d43883d4b 100644
--- a/addons/test_mail/__manifest__.py
+++ b/addons/test_mail/__manifest__.py
@@ -12,6 +12,7 @@ tests independently to functional aspects of other models. """,
     'depends': ['test_performance', 'mail'],
     'data': [
         'security/ir.model.access.csv',
+        'data/data.xml',
     ],
     'demo': [
         'data/demo.xml',