B TestHelper, CI: Work with older elixir version.

.gitlab-ci.yml

@@ -85,7 +85,7 @@ unit-testing:
   script:
     - mix ecto.create
     - mix ecto.migrate
-    - mix test --cover --preload-modules --warnings-as-errors
+    - mix test --cover --preload-modules
   coverage: '/^Line total: ([^ ]*%)$/'
   artifacts:
     reports:

test/test_helper.exs

@@ -2,6 +2,8 @@
 # Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
 # SPDX-License-Identifier: AGPL-3.0-only
 
+Code.put_compiler_option(:warnings_as_errors, true)
+
 os_exclude = if :os.type() == {:unix, :darwin}, do: [skip_on_mac: true], else: []
 ExUnit.start(exclude: [:federated, :erratic] ++ os_exclude)