[schedule/sensor testing 1/n] [RFC] build_schedule_context
Summary: (Depends on https://dagster.phacility.com/D7940) This diff provides a convenient fxn for constructing a schedule context. Right now, it is just a function, but there is an argument for making it a context manager that defaults the instance to instance.get().
Convert unit test decorators to use build_schedule_context instead of directly constructing ScheduleExecutionContext
Reviewers: sandyryza, alangenfeld, prha
Reviewed By: prha
Differential Revision: https://dagster.phacility.com/D7942