PURPOSE
Cleanup and improve post-related tests. As composer and posting methods will
soon be improved better ensure we don't break flows.
SPECIFICATIONS
Cleanup tests added for message_post and the related API (notify, log, with
view or template, ...) as well as sub-methods (notify, recipients computation
and classification, ...).
Use existing tools, reorder and add some details check on content. Add some
tests with attachments, notably with main_attachment management.
Task-2673913 (TestMail: Cleanup and improve test coverage)
Part-of: odoo/odoo#86393
Thibault Delavallée
41c3ed7693