Refactor and improve tests (#17386)

* Change account and user fabricators to simplify and improve tests

- `Fabricate(:account)` implicitly fabricates an associated `user` if
  no `domain` attribute is given (an account with `domain: nil` is
  considered a local account, but no user record was created), unless
  `user: nil` is passed
- `Fabricate(:account, user: Fabricate(:user))` should still be possible
  but is discouraged.

* Fix and refactor tests

- avoid passing unneeded attributes to `Fabricate(:user)` or
  `Fabricate(:account)`
- avoid embedding `Fabricate(:user)` into a `Fabricate(:account)` or the other
  way around
- prefer `Fabricate(:user, account_attributes: …)` to
  `Fabricate(:user, account: Fabricate(:account, …)`
- also, some tests were using remote accounts with local user records, which is
  not representative of production code.

1 files changed, 2 insertions, 2 deletions

diff --git a/spec/models/admin/account_action_spec.rb b/spec/models/admin/account_action_spec.rb
index 2366b9ca4..809c7fc46 100644
--- a/spec/models/admin/account_action_spec.rb
+++ b/spec/models/admin/account_action_spec.rb
@@ -5,8 +5,8 @@ RSpec.describe Admin::AccountAction, type: :model do
 
   describe '#save!' do
     subject              { account_action.save! }
-    let(:account)        { Fabricate(:account, user: Fabricate(:user, admin: true)) }
-    let(:target_account) { Fabricate(:account, user: Fabricate(:user)) }
+    let(:account)        { Fabricate(:user, admin: true).account }
+    let(:target_account) { Fabricate(:account) }
     let(:type)           { 'disable' }
 
     before do