tests: move test/helpers to test/test_helpers.

The Rails convention is for test/helpers to be used for testing the view
helpers in app/helpers. We were using it to store certain utility
methods instead. Move these to test/test_helpers so that test/helpers
can be used for its intended purpose.

test/unit/moderator/tag_batch_change_test.rb

@@ -1,10 +1,7 @@
 require "test_helper"
-require 'helpers/saved_search_test_helper'
 
 module Moderator
   class TagBatchChangeTest < ActiveSupport::TestCase
-    include SavedSearchTestHelper
-
     def setup
       super
       mock_saved_search_service!

test/unit/pool_test.rb

@@ -1,11 +1,8 @@
 # encoding: utf-8
 
 require 'test_helper'
-require 'helpers/pool_archive_test_helper'
 
 class PoolTest < ActiveSupport::TestCase
-  include PoolArchiveTestHelper
-
   setup do
     Timecop.travel(1.month.ago) do
       @user = FactoryGirl.create(:user)

test/unit/post_replacement_test.rb

@@ -1,9 +1,6 @@
 require 'test_helper'
-require 'helpers/iqdb_test_helper'
 
 class PostReplacementTest < ActiveSupport::TestCase
-  include IqdbTestHelper
-
   def upload_file(path, filename, &block)
     Tempfile.open do |file|
       file.write(File.read(path))

test/unit/post_sets/pool_test.rb

@@ -1,10 +1,7 @@
 require 'test_helper'
-require 'helpers/pool_archive_test_helper'
 
 module PostSets
   class PoolTest < ActiveSupport::TestCase
-    include PoolArchiveTestHelper
-
     context "In all cases" do
       setup do
         @user = FactoryGirl.create(:user)

test/unit/post_test.rb

@@ -1,13 +1,6 @@
 require 'test_helper'
-require 'helpers/pool_archive_test_helper'
-require 'helpers/saved_search_test_helper'
-require 'helpers/iqdb_test_helper'
 
 class PostTest < ActiveSupport::TestCase
-  include PoolArchiveTestHelper
-  include SavedSearchTestHelper
-  include IqdbTestHelper
-
   def assert_tag_match(posts, query)
     assert_equal(posts.map(&:id), Post.tag_match(query).pluck(:id))
   end

test/unit/saved_search_test.rb

@@ -1,9 +1,6 @@
 require 'test_helper'
-require 'helpers/saved_search_test_helper'
 
 class SavedSearchTest < ActiveSupport::TestCase
-  include SavedSearchTestHelper
-
   def setup
     super
     @user = FactoryGirl.create(:user)

test/unit/tag_alias_test.rb

@@ -1,9 +1,6 @@
 require 'test_helper'
-require 'helpers/saved_search_test_helper'
 
 class TagAliasTest < ActiveSupport::TestCase
-  include SavedSearchTestHelper
-
   context "A tag alias" do
     setup do
       Timecop.travel(1.month.ago) do

test/unit/upload_test.rb

@@ -1,11 +1,6 @@
 require 'test_helper'
-require 'helpers/iqdb_test_helper'
-require 'helpers/upload_test_helper'
 
 class UploadTest < ActiveSupport::TestCase
-  include IqdbTestHelper
-  include UploadTestHelper
-
   def setup
     super