Remove deprecated testcase class

test/support/task_test_case.rb

@@ -1,14 +0,0 @@
-class TaskTestCase < ActiveSupport::TestCase
-  setup do
-    # Rake tasks usually display some results, which mixes up with test results.
-    # This suppresses default stdout and makes Rails.env.test? checks unnecessary.
-    @original_stdout = $stdout
-    $stdout = File.open(File::NULL, 'w')
-    ActiveSupport::Deprecation.warn('`TaskTestCase` class will be removed soon.' \
-                                    ' Use `capture_io` and `assert_output` instead')
-  end
-
-  teardown do
-    $stdout = @original_stdout
-  end
-end

test/test_helper.rb

@@ -11,7 +11,6 @@ require 'capybara/rails'
 require 'capybara/minitest'
 require 'webmock/minitest'
 require 'support/rails5_assertions' # Remove once upgraded to Rails 5
-require 'support/task_test_case'
 
 Setting.address_processing = false
 Setting.registry_country_code = 'US'