* Introduced fab!, a helper that creates database state for a group
It's almost identical to let_it_be, except:
1. It creates a new object for each test by default,
2. You can disable it using PREFABRICATION=0
This change both speeds up specs (less strings to allocate) and helps catch
cases where methods in Discourse are mutating inputs.
Overall we will be migrating everything to use #frozen_string_literal: true
it will take a while, but this is the first and safest move in this direction
* Split alias levels in mentionable and messageable levels.
* Fixed some tests.
* Set messageable level to everyone by default.
* By defaults, groups are not mentionable or messageable.
* Made staff groups messageable by the system.
Daniel Waterworth
Sam Saffron
Bianca Nenciu
Guo Xiang Tan