Hopefully fixes flakes like:
```
not ok 1123 Chrome 102.0 - [undefined ms] - Global error: Uncaught Error: Unhandled request in test environment: /forum/u/eviltrout.json (PUT) at http://localhost:7357/assets/vendor.js, line 38378
While executing test: Unit | Utility | click-track: routes to absolute internal urls
---
browser log: |
{"type":"error","text":"Unhandled request in test environment: /forum/u/eviltrout.json (PUT)"}
{"type":"error","text":"Uncaught Error: Unhandled request in test environment: /forum/u/eviltrout.json (PUT) at http://localhost:7357/assets/vendor.js, line 38378\n","testContext":{"id":1123,"name":"Unit | Utility | click-track: routes to absolute internal urls","items":[],"state":"executing"}}
...
```
In the commit d8bf2810ff we hoisted
the userOptionFields array to a module-level variable, but kept
the code inside save() the same. This causes an issue where if
save() is called twice on the same user with some array of user
option fields, the userOptionFields array is mutated, which means
the second save is likely not saving the fields intended.
This commit fixes the issue by not mutating the array. We cannot
change them into consts though, because we have an API to add more
items to the array.
* pretender wasn't catching the request because it ran after this test finished
* restore wasn't needed, we do `sinon.restore()` after each test
The error was:
```
↪ Unit | Model | user::resolvedTimezone [✔]
↪ Unit | Utility | url::routeTo with prefixUnhandled request in test environment: /forum/u/chuck.json (PUT)
Error: Unhandled request in test environment: /forum/u/chuck.json (PUT)
at Pretender.server.unhandledRequest (discourse/tests/setup-tests:173:15)
at Pretender.handleRequest (pretender:400:14)
at FakeRequest.send (pretender:169:21)
at Object.send (jquery:10100:10)
at Function.ajax (jquery:9683:15)
at performAjax (discourse/app/lib/ajax:174:19)
at eval (discourse/app/lib/ajax:183:11)
at invokeCallback (ember:63104:17)
at publish (ember:63087:9)
at eval (ember:57463:16)
[✘]
```
A minimal reproduction:
`http://localhost:3001/qunit?seed=3&testId=da76996b&testId=e52a53e7`
Using arrow functions changes `this` context, which is undesired in tests, e.g. it makes it impossible to setup things like pretender (`this.server`) in `beforeEach` hooks.
Ember guides always use classic functions in examples (e.g. https://guides.emberjs.com/release/testing/test-types/), and that's what it uses in its own test suite, as do various addons and ember apps.
It was also already used in Discourse where `this` was required. Moving forward, it will be needed in more places as we migrate toward ember-cli.
(I might later add a custom rule to eslint-discourse-ember to enforce this)
We used many global functions to handle tests when they should be
imported like other libraries in our application. This also gets us
closer to the way Ember CLI prefers our tests to be laid out.
This is where they should be as far as ember is concerned. Note this is
a huge commit and we should be really careful everything continues to
work properly.
