models: remove belongs_to_creator macro.

The belongs_to_creator macro was used to initialize the creator_id field
to the CurrentUser. This made tests complicated because it meant you had
to create and set the current user every time you wanted to create an
object, when lead to the current user being set over and over again. It
also meant you had to constantly be aware of what the CurrentUser was in
many different contexts, which was often confusing. Setting creators
explicitly simplifies everything greatly.

test/unit/post_appeal_test.rb

@@ -3,14 +3,7 @@ require 'test_helper'
 class PostAppealTest < ActiveSupport::TestCase
   context "In all cases" do
     setup do
-      @alice = FactoryBot.create(:user)
-      CurrentUser.user = @alice
-      CurrentUser.ip_addr = "127.0.0.1"
-    end
-
-    teardown do
-      CurrentUser.user = nil
-      CurrentUser.ip_addr = nil
+      @alice = create(:user)
     end
 
     context "a user" do
@@ -19,37 +12,27 @@ class PostAppealTest < ActiveSupport::TestCase
       end
 
       should "not be able to appeal a post more than twice" do
-        assert_difference("PostAppeal.count", 1) do
-          @post_appeal = PostAppeal.create(:post => @post, :reason => "aaa")
-        end
-
-        assert_difference("PostAppeal.count", 0) do
-          @post_appeal = PostAppeal.create(:post => @post, :reason => "aaa")
-        end
+        @post_appeal = create(:post_appeal, post: @post, creator: @alice)
+        @post_appeal = build(:post_appeal, post: @post, creator: @alice)
 
+        assert_equal(false, @post_appeal.valid?)
         assert_includes(@post_appeal.errors.full_messages, "You have already appealed this post")
       end
 
       should "not be able to appeal more than 1 post in 24 hours" do
-        @post_appeal = PostAppeal.new(:post => @post, :reason => "aaa")
-        @post_appeal.expects(:appeal_count_for_creator).returns(1)
-        assert_difference("PostAppeal.count", 0) do
-          @post_appeal.save
-        end
+        @post_appeal = create(:post_appeal, post: @post, creator: @alice)
+        @post_appeal = build(:post_appeal, post: create(:post, is_deleted: true), creator: @alice)
+
+        assert_equal(false, @post_appeal.valid?)
         assert_equal(["You can appeal at most 1 post a day"], @post_appeal.errors.full_messages)
       end
 
       should "not be able to appeal an active post" do
         @post.update_attribute(:is_deleted, false)
-        assert_difference("PostAppeal.count", 0) do
-          @post_appeal = PostAppeal.create(:post => @post, :reason => "aaa")
-        end
-        assert_equal(["Post is active"], @post_appeal.errors.full_messages)
-      end
+        @post_appeal = build(:post_appeal, post: @post, creator: @alice)
 
-      should "initialize its creator" do
-        @post_appeal = PostAppeal.create(:post => @post, :reason => "aaa")
-        assert_equal(@alice.id, @post_appeal.creator_id)
+        assert_equal(false, @post_appeal.valid?)
+        assert_equal(["Post is active"], @post_appeal.errors.full_messages)
       end
     end
   end