Active Job: Correctly use the desired test adapter in tests

activejob/CHANGELOG.md

@@ -1,3 +1,16 @@
+*   All tests now respect the `active_job.queue_adapter` config
+
+    Previously if you had set `config.active_job.queue_adapter` in your `config/application.rb`
+    or `config/environments/test.rb` file, the adapter you selected was previously not used consistently
+    across all tests. In some tests your adapter would be used, but other tests would use the `TestAdapter`.
+
+    In Rails 7.2, all tests will respect the `queue_adapter` config if provided. If no config is provided,
+    the `TestAdapter` will continue to be used.
+
+    See [#48585](https://github.com/rails/rails/pull/48585) for more details.
+
+    *Alex Ghiculescu*
+
 *   Make Active Job transaction aware when used conjointly with Active Record.
 
     A common mistake with Active Job is to enqueue jobs from inside a transaction,

activejob/lib/active_job/queue_adapter.rb

@@ -15,7 +15,8 @@ module ActiveJob
   # = Active Job Queue adapter
   #
   # The +ActiveJob::QueueAdapter+ module is used to load the
-  # correct adapter. The default queue adapter is the +:async+ queue.
+  # correct adapter. The default queue adapter is +:async+,
+  # which loads the ActiveJob::QueueAdapters::AsyncAdapter.
   module QueueAdapter # :nodoc:
     extend ActiveSupport::Concern
 
@@ -24,21 +25,21 @@ module ActiveJob
       class_attribute :_queue_adapter, instance_accessor: false, instance_predicate: false
 
       delegate :queue_adapter, to: :class
-
-      self.queue_adapter = :async
     end
 
     # Includes the setter method for changing the active queue adapter.
     module ClassMethods
       # Returns the backend queue provider. The default queue adapter
-      # is the +:async+ queue. See QueueAdapters for more information.
+      # is +:async+. See QueueAdapters for more information.
       def queue_adapter
+        self.queue_adapter = :async if _queue_adapter.nil?
         _queue_adapter
       end
 
       # Returns string denoting the name of the configured queue adapter.
       # By default returns <tt>"async"</tt>.
       def queue_adapter_name
+        self.queue_adapter = :async if _queue_adapter_name.nil?
         _queue_adapter_name
       end
 

activejob/lib/active_job/railtie.rb

@@ -41,7 +41,7 @@ module ActiveJob
 
     initializer "active_job.set_configs" do |app|
       options = app.config.active_job
-      options.queue_adapter ||= :async
+      options.queue_adapter ||= (Rails.env.test? ? :test : :async)
 
       config.after_initialize do
         options.each do |k, v|

activejob/lib/active_job/test_helper.rb

@@ -39,10 +39,12 @@ module ActiveJob
     end
 
     def before_setup # :nodoc:
-      test_adapter = queue_adapter_for_test
-
       queue_adapter_changed_jobs.each do |klass|
-        klass.enable_test_adapter(test_adapter)
+        if (queue_adapter_specific_to_this_test_class = queue_adapter_for_test)
+          klass.enable_test_adapter(queue_adapter_specific_to_this_test_class)
+        elsif klass._queue_adapter.nil?
+          klass.enable_test_adapter(ActiveJob::QueueAdapters::TestAdapter.new)
+        end
       end
 
       clear_enqueued_jobs
@@ -61,7 +63,6 @@ module ActiveJob
     # Override this method to specify a different adapter. The adapter must
     # implement the same interface as ActiveJob::QueueAdapters::TestAdapter.
     def queue_adapter_for_test
-      ActiveJob::QueueAdapters::TestAdapter.new
     end
 
     # Asserts that the number of enqueued jobs matches the given number.
@@ -118,6 +119,8 @@ module ActiveJob
     #     end
     #   end
     def assert_enqueued_jobs(number, only: nil, except: nil, queue: nil, &block)
+      require_active_job_test_adapter!("assert_enqueued_jobs")
+
       if block_given?
         original_jobs = enqueued_jobs_with(only: only, except: except, queue: queue)
 
@@ -180,6 +183,8 @@ module ActiveJob
     #
     #   assert_enqueued_jobs 0, &block
     def assert_no_enqueued_jobs(only: nil, except: nil, queue: nil, &block)
+      require_active_job_test_adapter!("assert_no_enqueued_jobs")
+
       assert_enqueued_jobs 0, only: only, except: except, queue: queue, &block
     end
 
@@ -270,6 +275,8 @@ module ActiveJob
     #       end
     #     end
     def assert_performed_jobs(number, only: nil, except: nil, queue: nil, &block)
+      require_active_job_test_adapter!("assert_performed_jobs")
+
       if block_given?
         original_count = performed_jobs.size
 
@@ -338,6 +345,8 @@ module ActiveJob
     #
     #   assert_performed_jobs 0, &block
     def assert_no_performed_jobs(only: nil, except: nil, queue: nil, &block)
+      require_active_job_test_adapter!("assert_no_performed_jobs")
+
       assert_performed_jobs 0, only: only, except: except, queue: queue, &block
     end
 
@@ -394,6 +403,8 @@ module ActiveJob
     #     end
     #   end
     def assert_enqueued_with(job: nil, args: nil, at: nil, queue: nil, priority: nil, &block)
+      require_active_job_test_adapter!("assert_enqueued_with")
+
       expected = { job: job, args: args, at: at, queue: queue, priority: priority }.compact
       expected_args = prepare_args_for_assertion(expected)
       potential_matches = []
@@ -496,6 +507,8 @@ module ActiveJob
     #     end
     #   end
     def assert_performed_with(job: nil, args: nil, at: nil, queue: nil, priority: nil, &block)
+      require_active_job_test_adapter!("assert_performed_with")
+
       expected = { job: job, args: args, at: at, queue: queue, priority: priority }.compact
       expected_args = prepare_args_for_assertion(expected)
       potential_matches = []
@@ -604,7 +617,10 @@ module ActiveJob
     # If queue_adapter_for_test is overridden to return a different adapter,
     # +perform_enqueued_jobs+ will merely execute the block.
     def perform_enqueued_jobs(only: nil, except: nil, queue: nil, at: nil, &block)
-      return flush_enqueued_jobs(only: only, except: except, queue: queue, at: at) unless block_given?
+      unless block_given?
+        require_active_job_test_adapter!("perform_enqueued_jobs (without a block)")
+        return flush_enqueued_jobs(only: only, except: except, queue: queue, at: at)
+      end
 
       return _assert_nothing_raised_or_warn("perform_enqueued_jobs", &block) unless using_test_adapter?
 
@@ -646,6 +662,12 @@ module ActiveJob
     end
 
     private
+      def require_active_job_test_adapter!(method)
+        unless using_test_adapter?
+          raise ArgumentError.new("#{method} requires the Active Job test adapter, you're using #{queue_adapter.class.name}.")
+        end
+      end
+
       def using_test_adapter?
         queue_adapter.is_a?(ActiveJob::QueueAdapters::TestAdapter)
       end

activejob/test/cases/instrumentation_test.rb

@@ -23,6 +23,7 @@ class InstrumentationTest < ActiveSupport::TestCase
     assert_equal 1, events.size
   end
 
+  unless adapter_is?(:inline, :sneakers)
     test "retry emits an enqueue retry event" do
       events = subscribed("enqueue_retry.active_job") do
         perform_enqueued_jobs { RetryJob.perform_later("DefaultsError", 2) }
@@ -36,6 +37,7 @@ class InstrumentationTest < ActiveSupport::TestCase
       end
       assert_equal 1, events.size
     end
+  end
 
   test "discard emits a discard event" do
     events = subscribed("discard.active_job") do

activejob/test/cases/logging_test.rb

@@ -213,14 +213,14 @@ class LoggingTest < ActiveSupport::TestCase
     end
   end
 
+  unless adapter_is?(:inline, :sneakers)
     def test_enqueue_at_job_logging
       events = subscribed { HelloJob.set(wait_until: 24.hours.from_now).perform_later "Cristian" }
       assert_match(/Enqueued HelloJob \(Job ID: .*\) to .*? at.*Cristian/, @logger.messages)
       assert_equal(1, events.count)
       key, * = events.first
       assert_equal("enqueue_at.active_job", key)
-  rescue NotImplementedError
+    end
-    skip
   end
 
   def test_enqueue_at_job_log_error_when_callback_chain_is_halted
@@ -244,14 +244,14 @@ class LoggingTest < ActiveSupport::TestCase
     assert_equal("enqueue_at.active_job", key)
   end
 
+  unless adapter_is?(:inline, :sneakers)
     def test_enqueue_in_job_logging
       events = subscribed { HelloJob.set(wait: 2.seconds).perform_later "Cristian" }
       assert_match(/Enqueued HelloJob \(Job ID: .*\) to .*? at.*Cristian/, @logger.messages)
       assert_equal(1, events.count)
       key, * = events.first
       assert_equal("enqueue_at.active_job", key)
-  rescue NotImplementedError
+    end
-    skip
   end
 
   def test_enqueue_log_when_enqueue_error_is_set
@@ -290,18 +290,21 @@ class LoggingTest < ActiveSupport::TestCase
     assert_no_match(/Error performing RescueJob \(Job ID: .*?\) from .*? in .*ms: ArgumentError \(Hair too good\):\n.*\brescue_job\.rb:\d+:in .*perform'/, @logger.messages)
   end
 
+  unless adapter_is?(:inline, :sneakers)
     def test_enqueue_retry_logging
       perform_enqueued_jobs do
         RetryJob.perform_later "DefaultsError", 2
         assert_match(/Retrying RetryJob \(Job ID: .*?\) after \d+ attempts in 3 seconds, due to a DefaultsError.*\./, @logger.messages)
       end
     end
+  end
 
   def test_enqueue_retry_logging_on_retry_job
     perform_enqueued_jobs { RescueJob.perform_later "david" }
     assert_match(/Retrying RescueJob \(Job ID: .*?\) after \d+ attempts in 0 seconds\./, @logger.messages)
   end
 
+  unless adapter_is?(:inline, :sneakers)
     def test_retry_stopped_logging
       perform_enqueued_jobs do
         RetryJob.perform_later "CustomCatchError", 6
@@ -316,6 +319,7 @@ class LoggingTest < ActiveSupport::TestCase
         assert_match(/Stopped retrying RetryJob \(Job ID: .*?\) due to a DefaultsError.*, which reoccurred on \d+ attempts\./, @logger.messages)
       end
     end
+  end
 
   def test_discard_logging
     perform_enqueued_jobs do

activejob/test/cases/queue_adapter_test.rb

@@ -53,6 +53,19 @@ class QueueAdapterTest < ActiveJob::TestCase
     assert_equal base_queue_adapter, child_job_three.queue_adapter, "child_job_three's queue adapter should remain unchanged"
   end
 
+  test "should default to :async adapter if no adapters are set at all" do
+    ActiveJob::Base.disable_test_adapter
+    _queue_adapter_was = ActiveJob::Base._queue_adapter
+    _queue_adapter_name_was = ActiveJob::Base._queue_adapter_name
+    ActiveJob::Base._queue_adapter = ActiveJob::Base._queue_adapter_name = nil
+
+    assert_equal "async", ActiveJob::Base.queue_adapter_name
+    assert_kind_of ActiveJob::QueueAdapters::AsyncAdapter, ActiveJob::Base.queue_adapter
+  ensure
+    ActiveJob::Base._queue_adapter = _queue_adapter_was
+    ActiveJob::Base._queue_adapter_name = _queue_adapter_name_was
+  end
+
   test "should extract a reasonable name from a class instance" do
     child_job = Class.new(ActiveJob::Base)
     child_job.queue_adapter = ActiveJob::QueueAdapters::StubOneAdapter.new

activejob/test/cases/test_case_test.rb

@@ -20,10 +20,37 @@ class ActiveJobTestCaseTest < ActiveJob::TestCase
   end
 
   def test_set_test_adapter
-    assert_kind_of ActiveJob::QueueAdapters::TestAdapter, queue_adapter
+    # The queue adapter the job uses depends on the Active Job config.
+    # See https://github.com/rails/rails/pull/48585 for logic.
+    expected = case ActiveJob::Base.queue_adapter_name.to_sym
+               when :test
+                 ActiveJob::QueueAdapters::TestAdapter
+               when :inline
+                 ActiveJob::QueueAdapters::InlineAdapter
+               when :async
+                 ActiveJob::QueueAdapters::AsyncAdapter
+               when :backburner
+                 ActiveJob::QueueAdapters::BackburnerAdapter
+               when :delayed_job
+                 ActiveJob::QueueAdapters::DelayedJobAdapter
+               when :queue_classic
+                 ActiveJob::QueueAdapters::QueueClassicAdapter
+               when :resque
+                 ActiveJob::QueueAdapters::ResqueAdapter
+               when :sidekiq
+                 ActiveJob::QueueAdapters::SidekiqAdapter
+               when :sneakers
+                 ActiveJob::QueueAdapters::SneakersAdapter
+               when :sucker_punch
+                 ActiveJob::QueueAdapters::SuckerPunchAdapter
+               else
+                 raise NotImplementedError.new
+    end
+
+    assert_kind_of expected, queue_adapter
   end
 
   def test_does_not_perform_enqueued_jobs_by_default
-    assert_nil queue_adapter.perform_enqueued_jobs
+    assert_nil ActiveJob::QueueAdapters::TestAdapter.new.perform_enqueued_jobs
   end
 end

activejob/test/cases/test_helper_test.rb

@@ -3,6 +3,7 @@
 require "helper"
 require "active_support/core_ext/time"
 require "active_support/core_ext/date"
+require "active_support/concern"
 require "zeitwerk"
 require "jobs/hello_job"
 require "jobs/logging_job"
@@ -14,7 +15,30 @@ require "jobs/inherited_job"
 require "jobs/multiple_kwargs_job"
 require "models/person"
 
+module DoNotPerformEnqueuedJobs
+  extend ActiveSupport::Concern
+
+  included do
+    setup do
+      # /rails/activejob/test/adapters/test.rb sets these configs to true, but
+      # in this specific case we want to test enqueueing behaviour.
+      @perform_enqueued_jobs = queue_adapter.perform_enqueued_jobs
+      @perform_enqueued_at_jobs = queue_adapter.perform_enqueued_at_jobs
+      queue_adapter.perform_enqueued_jobs = queue_adapter.perform_enqueued_at_jobs = false
+    end
+
+    teardown do
+      queue_adapter.perform_enqueued_jobs = @perform_enqueued_jobs
+      queue_adapter.perform_enqueued_at_jobs = @perform_enqueued_at_jobs
+    end
+  end
+end
+
+
 class EnqueuedJobsTest < ActiveJob::TestCase
+  if adapter_is?(:test)
+    include DoNotPerformEnqueuedJobs
+
     def test_assert_enqueued_jobs
       assert_nothing_raised do
         assert_enqueued_jobs 1 do
@@ -779,9 +803,13 @@ class EnqueuedJobsTest < ActiveJob::TestCase
       assert_enqueued_jobs 1
       assert_performed_jobs 1
     end
+  end
 end
 
 class PerformedJobsTest < ActiveJob::TestCase
+  if adapter_is?(:test)
+    include DoNotPerformEnqueuedJobs
+
     def test_perform_enqueued_jobs_with_only_option_doesnt_leak_outside_the_block
       assert_nil queue_adapter.filter
       perform_enqueued_jobs only: HelloJob do
@@ -2063,6 +2091,63 @@ class PerformedJobsTest < ActiveJob::TestCase
 
       assert_equal 2, queue_adapter.performed_jobs.count
     end
+  end
+end
+
+class NotTestAdapterTest < ActiveJob::TestCase
+  unless adapter_is?(:test)
+    setup do
+      @adapter = queue_adapter.class.name
+    end
+
+    test "assert_enqueued_jobs raises" do
+      assert_raises ArgumentError, match: "assert_enqueued_jobs requires the Active Job test adapter, you're using #{@adapter}" do
+        assert_enqueued_jobs(0) { }
+      end
+    end
+
+    test "assert_no_enqueued_jobs raises" do
+      assert_raises ArgumentError, match: "assert_no_enqueued_jobs requires the Active Job test adapter, you're using #{@adapter}" do
+        assert_no_enqueued_jobs { }
+      end
+    end
+
+    test "assert_performed_jobs raises" do
+      assert_raises ArgumentError, match: "assert_performed_jobs requires the Active Job test adapter, you're using #{@adapter}" do
+        assert_performed_jobs(0) { }
+      end
+    end
+
+    test "assert_no_performed_jobs raises" do
+      assert_raises ArgumentError, match: "assert_no_performed_jobs requires the Active Job test adapter, you're using #{@adapter}" do
+        assert_no_performed_jobs { }
+      end
+    end
+
+    test "assert_enqueued_with raises" do
+      assert_raises ArgumentError, match: "assert_enqueued_with requires the Active Job test adapter, you're using #{@adapter}" do
+        assert_enqueued_with { }
+      end
+    end
+
+    test "assert_performed_with raises" do
+      assert_raises ArgumentError, match: "assert_performed_with requires the Active Job test adapter, you're using #{@adapter}" do
+        assert_performed_with { }
+      end
+    end
+
+    test "perform_enqueued_jobs without a block" do
+      assert_raises ArgumentError, match: "perform_enqueued_jobs (without a block) requires the Active Job test adapter, you're using #{@adapter}" do
+        perform_enqueued_jobs
+      end
+    end
+
+    test "perform_enqueued_jobs with a block does not raise" do
+      assert_nothing_raised do
+        perform_enqueued_jobs { }
+      end
+    end
+  end
 end
 
 class AdapterIsNotTestAdapterTest < ActiveJob::TestCase
@@ -2092,17 +2177,17 @@ class OverrideQueueAdapterTest < ActiveJob::TestCase
 end
 
 class InheritedJobTest < ActiveJob::TestCase
-  def test_queue_adapter_is_test_adapter
+  def test_queue_adapter_is_inline_adapter_because_it_is_set_on_the_job_class
-    assert_instance_of ActiveJob::QueueAdapters::TestAdapter, InheritedJob.queue_adapter
+    assert_instance_of ActiveJob::QueueAdapters::InlineAdapter, InheritedJob.queue_adapter
   end
 end
 
 class QueueAdapterJobTest < ActiveJob::TestCase
-  def test_queue_adapter_is_test_adapter
+  def test_queue_adapter_is_is_inline_adapter_because_it_is_set_on_the_job_class
     Zeitwerk.with_loader do |loader|
       loader.push_dir("test/jobs")
       loader.setup
-      assert_instance_of ActiveJob::QueueAdapters::TestAdapter, QueueAdapterJob.queue_adapter
+      assert_instance_of ActiveJob::QueueAdapters::InlineAdapter, QueueAdapterJob.queue_adapter
     ensure
       loader.unload
     end

guides/source/upgrading_ruby_on_rails.md

@@ -81,6 +81,17 @@ Upgrading from Rails 7.1 to Rails 7.2
 
 For more information on changes made to Rails 7.2 please see the [release notes](7_2_release_notes.html).
 
+### All tests now respect the `active_job.queue_adapter` config
+
+If you have set `config.active_job.queue_adapter` in your `config/application.rb` or `config/environments/test.rb` file,
+the adapter you selected was previously not used consistently across all tests. In some tests your adapter would be
+used, but other tests would use the `TestAdapter`.
+
+In Rails 7.2, all tests will respect the `queue_adapter` config if provided. This may cause test errors, if you had
+set the `queue_adapter` config to something other than `:test`, but written tests in a way that was dependent on the `TestAdapter`.
+
+If no config is provided, the `TestAdapter` will continue to be used.
+
 Upgrading from Rails 7.0 to Rails 7.1
 -------------------------------------
 

railties/test/application/active_job_adapter_test.rb

@@ -0,0 +1,217 @@
+# frozen_string_literal: true
+
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  class ActiveJobAdapterTest < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      @old = ENV["PARALLEL_WORKERS"]
+      ENV["PARALLEL_WORKERS"] = "0"
+
+      build_app
+    end
+
+    def teardown
+      ENV["PARALLEL_WORKERS"] = @old
+
+      teardown_app
+    end
+
+    test "config set via application.rb" do
+      add_to_config "config.active_job.queue_adapter = :inline"
+      make_inline_test_file
+      assert_successful_test_run "integration/config_test.rb"
+    end
+
+    test "config set via environment config" do
+      add_to_config "config.active_job.queue_adapter = :async"
+      app_file "config/environments/test.rb", <<-RUBY
+        Rails.application.configure do
+          config.active_job.queue_adapter = :inline
+        end
+      RUBY
+      make_inline_test_file
+      assert_successful_test_run "integration/config_test.rb"
+    end
+
+    test "config is set for production, but test uses defaults" do
+      app_file "config/environments/production.rb", <<-RUBY
+        Rails.application.configure do
+          config.active_job.queue_adapter = :sidekiq
+        end
+      RUBY
+      make_test_test_file
+      assert_successful_test_run "integration/config_test.rb"
+    end
+
+    private
+      def make_inline_test_file
+        app_file "test/integration/config_test.rb", <<-RUBY
+        require "test_helper"
+
+        class RailsConfigUnitTest < ActiveSupport::TestCase
+          test "the Inline Active Job adapter is used in unit tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::InlineAdapter), adapter
+            assert_equal :inline, Rails.application.config.active_job.queue_adapter
+          end
+        end
+
+        class RailsConfigIntegrationTest < ActionDispatch::IntegrationTest
+          test "the Inline Active Job adapter is used in integration tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::InlineAdapter), adapter
+            assert_equal :inline, Rails.application.config.active_job.queue_adapter
+
+            # ActionDispatch::IntegrationTest includes ActiveJob::TestHelper,
+            # which adds a bunch of assertions. But these assertions only work
+            # if the test adapter is TestAdapter. So for other test adapters,
+            # we raise an error if the method is called.
+            assert_raise ArgumentError, "assert_enqueued_jobs requires the Active Job test adapter, you're using ActiveJob::QueueAdapters::InlineAdapter" do
+              assert_no_enqueued_jobs {}
+            end
+          end
+        end
+
+        class RailsConfigJobTest < ActiveJob::TestCase
+          test "the Inline Active Job adapter is used in job tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::InlineAdapter), adapter
+            assert_equal :inline, Rails.application.config.active_job.queue_adapter
+
+            # ActiveJob::TesTCase includes ActiveJob::TestHelper,
+            # which adds a bunch of assertions. But these assertions only work
+            # if the test adapter is TestAdapter. So for other test adapters,
+            # we raise an error if the method is called.
+            assert_raise ArgumentError, "assert_enqueued_jobs requires the Active Job test adapter, you're using ActiveJob::QueueAdapters::InlineAdapter" do
+              assert_no_enqueued_jobs {}
+            end
+          end
+        end
+
+        class RailsConfigMailerTest < ActionMailer::TestCase
+          test "the Inline Active Job adapter is used in mailer tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::InlineAdapter), adapter
+            assert_equal :inline, Rails.application.config.active_job.queue_adapter
+
+            # ActionMailer::TestHelper includes ActiveJob::TestHelper
+            # So this just asserts that we haven't broken Action Mailer assertions that
+            # depend on Active Job:
+            assert_emails(0) {}
+            assert_emails(0)
+          end
+        end
+
+        class RailsConfigHelperTest < ActionView::TestCase
+          test "the Inline Active Job adapter is used in helper tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::InlineAdapter), adapter
+            assert_equal :inline, Rails.application.config.active_job.queue_adapter
+          end
+        end
+
+        class RailsConfigControllerTest < ActionController::TestCase
+          test "the Inline Active Job adapter is used in controller tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::InlineAdapter), adapter
+            assert_equal :inline, Rails.application.config.active_job.queue_adapter
+          end
+        end
+
+        class RailsConfigSystemTest < ActionDispatch::SystemTestCase
+          test "the Inline Active Job adapter is used in system tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::InlineAdapter), adapter
+            assert_equal :inline, Rails.application.config.active_job.queue_adapter
+          end
+        end
+        RUBY
+      end
+
+      def make_test_test_file
+        app_file "test/integration/config_test.rb", <<-RUBY
+        require "test_helper"
+
+        class RailsConfigUnitTest < ActiveSupport::TestCase
+          test "the Test Active Job adapter is used in unit tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::TestAdapter), adapter
+            assert_equal :test, Rails.application.config.active_job.queue_adapter
+          end
+        end
+
+        class RailsConfigIntegrationTest < ActionDispatch::IntegrationTest
+          test "the Test Active Job adapter is used in integration tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::TestAdapter), adapter
+            assert_equal :test, Rails.application.config.active_job.queue_adapter
+
+            assert_nothing_raised do
+              assert_no_enqueued_jobs {}
+            end
+          end
+        end
+
+        class RailsConfigJobTest < ActiveJob::TestCase
+          test "the Test Active Job adapter is used in job tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::TestAdapter), adapter
+            assert_equal :test, Rails.application.config.active_job.queue_adapter
+
+            assert_nothing_raised do
+              assert_no_enqueued_jobs {}
+            end
+          end
+        end
+
+        class RailsConfigMailerTest < ActionMailer::TestCase
+          test "the Test Active Job adapter is used in mailer tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::TestAdapter), adapter
+            assert_equal :test, Rails.application.config.active_job.queue_adapter
+
+            assert_emails(0) {}
+            assert_emails(0)
+          end
+        end
+
+        class RailsConfigHelperTest < ActionView::TestCase
+          test "the Test Active Job adapter is used in helper tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::TestAdapter), adapter
+            assert_equal :test, Rails.application.config.active_job.queue_adapter
+          end
+        end
+
+        class RailsConfigControllerTest < ActionController::TestCase
+          test "the Test Active Job adapter is used in controller tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::TestAdapter), adapter
+            assert_equal :test, Rails.application.config.active_job.queue_adapter
+          end
+        end
+
+        class RailsConfigSystemTest < ActionDispatch::SystemTestCase
+          test "the Test Active Job adapter is used in system tests" do
+            adapter = ActiveJob::Base.queue_adapter
+            assert adapter.is_a?(ActiveJob::QueueAdapters::TestAdapter), adapter
+            assert_equal :test, Rails.application.config.active_job.queue_adapter
+          end
+        end
+        RUBY
+      end
+
+      def assert_successful_test_run(name)
+        result = run_test_file(name)
+        assert_equal 0, $?.to_i, result
+        result
+      end
+
+      def run_test_file(name)
+        rails "test", "#{app_path}/test/#{name}", allow_failure: true
+      end
+  end
+end

railties/test/application/configuration_test.rb

@@ -4635,6 +4635,42 @@ module ApplicationTests
       assert_equal "SQLite", ActiveRecord::Base.lease_connection.adapter_name
     end
 
+    ["development", "production"].each do |env|
+      test "active job adapter is async in #{env}" do
+        app(env)
+        assert_equal :async, Rails.application.config.active_job.queue_adapter
+        adapter = ActiveJob::Base.queue_adapter
+        assert_instance_of ActiveJob::QueueAdapters::AsyncAdapter, adapter
+      end
+
+      test "active job adapter can be overridden in #{env} via application.rb" do
+        add_to_config "config.active_job.queue_adapter = :inline"
+        app(env)
+        assert_equal :inline, Rails.application.config.active_job.queue_adapter
+        adapter = ActiveJob::Base.queue_adapter
+        assert_instance_of ActiveJob::QueueAdapters::InlineAdapter, adapter
+      end
+
+      test "active job adapter can be overridden in #{env} via environment config" do
+        app_file "config/environments/#{env}.rb", <<-RUBY
+          Rails.application.configure do
+            config.active_job.queue_adapter = :inline
+          end
+        RUBY
+        app(env)
+        assert_equal :inline, Rails.application.config.active_job.queue_adapter
+        adapter = ActiveJob::Base.queue_adapter
+        assert_instance_of ActiveJob::QueueAdapters::InlineAdapter, adapter
+      end
+    end
+
+    test "active job adapter is `:test` in test environment" do
+      app "test"
+      assert_equal :test, Rails.application.config.active_job.queue_adapter
+      adapter = ActiveJob::Base.queue_adapter
+      assert_instance_of ActiveJob::QueueAdapters::TestAdapter, adapter
+    end
+
     private
       def set_custom_config(contents, config_source = "custom".inspect)
         app_file "config/custom.yml", contents