fix(Home): Tests succeed locally [TDP-202]

[mmiermans]

Goal

Allow tests to be run locally. Tests in test_home_slate_lineup.py failed locally because the DiContainer.init() was not called on startup during tests that use the AsyncClient.

Reference

Background on problem and solution:

• AsyncClient ignores the startup and shutdown events tiangolo/fastapi#2003 (comment)

Tickets:

• https://getpocket.atlassian.net/browse/TDP-202

Implementation Decisions

• Going forward I'm trying to move to the pytest style, and away from the unittest style. A pytest fixture could remove the duplicate code used here to instantiate an app with a LifespanManager, as you can see in the above Github issue. Fixtures don't combine with unittest patching, which these tests rely on, and I decided to punt on a larger refactor of these tests.