Previous commit 479c0a3051 was done with the assumption that this info was defined on user serializer but it was actually defined on post serializer in core. This commit extends the user serializer for messages to add this data to the user.
Also correctly adds serializer test to ensure we actually have this data.
1. `test()` and `render()` instead of `componentTest()`
2. Angle brackets
3. `strictEqual()`/`true()`/`false()` assertions
This removes all remaining uses of `componentTest` from core
Joffrey JAFFEUX
Jarek Radosz
Roman Rizzi