Session problem in unit tests

Tests that require a logged in user and other data from the fixtures are not correctly working.

I will create a failing test in a new branch for this.

@Guido: if you want to work on it: nice! Time boxed to 4 hours

Start by reproducing the unit-test failure described for tests that require a logged-in user and fixture data, then inspect the session and fixture setup used by those tests. Add the planned failing test on a branch and consider the work complete when the affected tests correctly use the logged-in session and fixture data.

由索引模型根據 Issue 內容生成。