Tests: Sort out usage of content folder in tests

[kirrg001]

no issue

• use latest casper in test fixtures
• removed fixtures/theme (was unused)
• never ever use the root content folder for tests
• if we start/fork Ghost for the tests, we use the a tmp folder
• this change is required to for an upcoming PR (✨ Upload/Download redirects #9029)
• i've added a TODO to create a helper fn for stopping the ghost server, so we can cleanup the tmp folder, but it's a folder in your tmp directory anyway. but we should add the cleanup logic soon

Changes look huge, but they aren't:

• use the latest casper in our test fixtures (it's just a copy and paste of the current casper theme)
  • otherwise we use an old version of casper for testing
• it's a little annoying that each time casper introduces a breaking change, we have to replace the files, but i have no other solution right now, which is easy to implement)
• use a tmp folder instead, see https://github.com/TryGhost/Ghost/pull/9034/files#diff-085888ce4e458820a35b19844ba3d990R820

[kirrg001]

@ErisDS Ah now i found the tests who added TODO's for this problem. https://github.com/TryGhost/Ghost/blob/master/core/test/functional/routes/channel_spec.js
I will quickly double check this test file.

[ErisDS]

Is it possible, to have a secondary git submodule of casper in the tests 🤔

[ErisDS]

^ is just an idea for later, this LGTM let me know when you've finished checking other tests

[kirrg001]

Is it possible, to have a secondary git submodule of casper in the tests 🤔
^ is just an idea for later, this LGTM let me know when you've finished checking other tests

Yeah that could work. But agree, nothing to try out for now (not urgent enough).

[kirrg001]

Sorted the channels test out, see my second commit (contains context for you in the commit message) 302a3e9. You can squash both together 😱