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.
Close#2334
To avoid merge conflicts, I've deferred removing the aliasing logic in `prepareExamples`. That whole function will be refactored momentarily, and there's also #2339 open.
This picks up @RedSparr0w's work in #1802.
1. The handler for the static badge is moved into its own service with a synchronous handler. Avoiding an async call may make the static badges slightly faster, though it may be worth profiling this if it turns out we want asynchronous static badges in the future. If it doesn't make a performance difference we could make this handler `async` like the others.
2. Most of the custom static-badge logic is in a BaseStaticBadge base class.
3. Rewrite the static Gitter badge to use BaseStaticBadge.
4. A bit of minor cleanup in related functions.
The term “url” is overloaded in services, to refer to the Shields route and also the API URL. Calling the Shields URL a “route” is on the whole more descriptive, and makes it clearer and more obvious which one of these we’re talking about. It’s a small thing, though seems like an improvement.
We have a few functions called `buildUrl`. I’ve renamed them to `buildRoute` when they refer to routes, and left them as `buildUrl` when they refer to API URLs.
I included a minor style tweak and some formatting cleanup in `TUTORIAL.md`.
all-badge-examples is a common cause of merge conflicts. It’s difficult to adjust the badge categorization in that file – or to understand the diff – because it requires moving a block from one point to another. It’s much easier to edit a badge’s category in one place.
This starts the process of breaking up what’s left of that file, following up on the work from #1931. New-style services can only be in one category, which means legacy service examples have to be split along category lines. I split out separate legacy service classes where I could do so easily, leaving behind the ones which require more work, for one reason or another.
