Remove AS::Testing::Stream in favor of Minitest assert_output

.rubocop_todo.yml

@@ -222,7 +222,6 @@ Style/TrailingBlankLines:
     - 'test/adapter/null_test.rb'
     - 'test/serializers/cache_test.rb'
     - 'test/serializers/fieldset_test.rb'
-    - 'test/support/stream_capture.rb'
 
 # Offense count: 5
 # Cop supports --auto-correct.

test/action_controller/serialization_test.rb

@@ -3,7 +3,6 @@ require 'test_helper'
 module ActionController
   module Serialization
     class ImplicitSerializerTest < ActionController::TestCase
-      include ActiveSupport::Testing::Stream
       class ImplicitSerializationTestController < ActionController::Base
         include SerializationTesting
         def render_using_implicit_serializer
@@ -438,9 +437,9 @@ module ActionController
             false
           end
         end.new
-        assert_match(/adapter: false/, (capture(:stderr) do
+        assert_output(nil, /adapter: false/) do
           controller.get_serializer(Profile.new)
-        end))
+        end
       end
 
       def test_dont_warn_overridding_use_adapter_as_truthy_on_controller_instance
@@ -449,9 +448,9 @@ module ActionController
             true
           end
         end.new
-        assert_equal '', (capture(:stderr) do
+        assert_output(nil, '') do
           controller.get_serializer(Profile.new)
-        end)
+        end
       end
 
       def test_render_event_is_emmited

test/array_serializer_test.rb

@@ -6,11 +6,11 @@ module ActiveModel
     # Minitest.run_one_method isn't present in minitest 4
     if $minitest_version > 4 # rubocop:disable Style/GlobalVars
       class ArraySerializerTest < CollectionSerializerTest
-        extend ActiveSupport::Testing::Stream
+        extend Minitest::Assertions
         def self.run_one_method(*)
-          stderr = (capture(:stderr) do
+          _, stderr = capture_io do
             super
-          end)
+          end
           if stderr !~ /Calling deprecated ArraySerializer/
             fail Minitest::Assertion, stderr
           end
@@ -22,14 +22,13 @@ module ActiveModel
       end
     else
       class ArraySerializerTest < ActiveSupport::TestCase
-        extend ActiveSupport::Testing::Stream
         def test_json_key_with_root_warns_when_using_array_serializer
-          stderr = (capture(:stderr) do
+          _, stderr = capture_io do
             comment = Comment.new
             post = Post.new
             serializer = ArraySerializer.new([comment, post])
             assert_equal 'comments', serializer.json_key
-          end)
+          end
           assert_match(/Calling deprecated ArraySerializer/, stderr)
         end
       end

test/serializers/cache_test.rb

@@ -3,8 +3,6 @@ require 'tmpdir'
 require 'tempfile'
 module ActiveModelSerializers
   class CacheTest < ActiveSupport::TestCase
-    include ActiveSupport::Testing::Stream
-
     def setup
       ActionController::Base.cache_store.clear
       @comment        = Comment.new(id: 1, body: 'ZOMG A COMMENT')
@@ -222,10 +220,10 @@ module ActiveModelSerializers
     def test_warn_on_serializer_not_defined_in_file
       called = false
       serializer = Class.new(ActiveModel::Serializer)
-      assert_match(/_cache_digest/, (capture(:stderr) do
+      assert_output(nil, /_cache_digest/) do
         serializer.digest_caller_file('')
         called = true
-      end))
+      end
       assert called
     end
 

test/support/stream_capture.rb

@@ -1,50 +0,0 @@
-# Use cleaner stream testing interface from Rails 5 if available
-# see https://github.com/rails/rails/blob/29959eb59d/activesupport/lib/active_support/testing/stream.rb
-begin
-  require 'active_support/testing/stream'
-rescue LoadError
-  require 'tempfile'
-  module ActiveSupport
-    module Testing
-      module Stream #:nodoc:
-        private
-
-        def silence_stream(stream)
-          old_stream = stream.dup
-          stream.reopen(IO::NULL)
-          stream.sync = true
-          yield
-        ensure
-          stream.reopen(old_stream)
-          old_stream.close
-        end
-
-        def quietly
-          silence_stream(STDOUT) do
-            silence_stream(STDERR) do
-              yield
-            end
-          end
-        end
-
-        def capture(stream)
-          stream = stream.to_s
-          captured_stream = Tempfile.new(stream)
-          stream_io = eval("$#{stream}") # rubocop:disable Lint/Eval
-          origin_stream = stream_io.dup
-          stream_io.reopen(captured_stream)
-
-          yield
-
-          stream_io.rewind
-          return captured_stream.read
-        ensure
-          captured_stream.close
-          captured_stream.unlink
-          stream_io.reopen(origin_stream)
-        end
-      end
-    end
-  end
-end
-

test/test_helper.rb

@@ -43,8 +43,6 @@ end
 require 'minitest/reporters'
 Minitest::Reporters.use!
 
-require 'support/stream_capture'
-
 require 'support/rails_app'
 
 require 'support/test_case'