Resolves #45220 (one of many small PRs, we are close) ## Testing - [X] QA'd all new/changed functionality manually <!-- This is an auto-generated comment: release notes by coderabbit.ai --> ## Summary by CodeRabbit * **Tests** * Refactored test infrastructure for scheduling components to use centralized test utilities. --- **Note:** This release contains no user-facing changes. All modifications are internal testing and code organization improvements. <!-- review_stack_entry_start --> [](https://app.coderabbit.ai/change-stack/fleetdm/fleet/pull/45609) <!-- review_stack_entry_end --> <!-- end of auto-generated comment: release notes by coderabbit.ai -->