This will definitely save time, and ensure more uniformity.
It moves the `createServiceTester()` calls to a different place from where I'd like them, though I'm happy to have them checked by the linter.
Closes#2701
Fixes#2876 with @paulmelnikow's suggestion
Moved imports of `ServiceTester` and `createServiceTester` to a separate file so that dev dependencies are not imported by service classes.
Continue to implement #2698:
- Add `core/base-service/index.js` (but hold off on moving the things it imports)
- Add shortcuts in `services/index.js` for Base*Service, errors, and deprecatedService. This file will be streamlined later to avoid cluttering it with rarely used bits.
- Apply consistent ordering of imports and use of `module.exports` in testers.
- Remove some renaming of imports.
- Remove obsolete tests here and there.
This is a bit of sugar that reduces the boilerplate for creating testers in what I expect will become the standard case: a service in `foo/foo-thing.service.js` with its tests in `foo/foo-thing.tester.js`.
This makes a small stylistic change, which is to name the service by its CamelCase class name rather than an invented snake-case ID. Whereas before the name was specified in `class FooThing extends Base[Json]Service` and a second time in the tester, it now only needs to be specified once.
