Treat warnings as errors outside of tests.

test/support/builders/activity_builder.ex

@@ -1,5 +1,4 @@
 defmodule Pleroma.Builders.ActivityBuilder do
-  alias Pleroma.Builders.UserBuilder
   alias Pleroma.Web.ActivityPub.ActivityPub
 
   def build(data \\ %{}, opts \\ %{}) do

test/support/http_request_mock.ex

@@ -13,7 +13,7 @@ defmodule HttpRequestMock do
     with {:ok, res} <- apply(__MODULE__, method, [url, query, body, headers]) do
       res
     else
-      {_, r} = error ->
+      {_, _r} = error ->
         # Logger.warn(r)
         error
     end

test/support/websub_mock.ex

@@ -0,0 +1,5 @@
+defmodule Pleroma.Web.WebsubMock do
+  def verify(sub) do
+    {:ok, sub}
+  end
+end