diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 642f5c92..ec46b389 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -69,9 +69,6 @@ jobs:
           mysql -uroot -h localhost -proot -e "CREATE DATABASE job_iteration_test;"
       - name: Ruby tests
         run: bundle exec rake test
-        env:
-          REDIS_HOST: localhost
-          REDIS_PORT: ${{ job.services.redis.ports[6379] }}
 
   lint:
     runs-on: ubuntu-latest
diff --git a/test/integration/integration_behaviour.rb b/test/integration/integration_behaviour.rb
index 89dd3602..1fca001d 100644
--- a/test/integration/integration_behaviour.rb
+++ b/test/integration/integration_behaviour.rb
@@ -50,33 +50,33 @@ module IntegrationBehaviour
         failed_job_error_class_name,
       )
     end
+  end
 
-    private
+  private
 
-    # Should return the symbol to use when configuring the adapter
-    #     ActiveJob::Base.queue_adapter = adapter
-    def adapter
-      raise NotImplemented, "#{self.class.name} must implement #{__method__}"
-    end
+  # Should return the symbol to use when configuring the adapter
+  #     ActiveJob::Base.queue_adapter = adapter
+  def adapter
+    raise NotImplemented, "#{self.class.name} must implement #{__method__}"
+  end
 
-    # Should start the job worker process and allow it to work the queue
-    def start_worker_and_wait
-      raise NotImplemented, "#{self.class.name} must implement #{__method__}"
-    end
+  # Should start the job worker process and allow it to work the queue
+  def start_worker_and_wait
+    raise NotImplemented, "#{self.class.name} must implement #{__method__}"
+  end
 
-    # Should return the number of jobs currently enqueued for processing
-    def queue_size
-      raise NotImplemented, "#{self.class.name} must implement #{__method__}"
-    end
+  # Should return the number of jobs currently enqueued for processing
+  def queue_size
+    raise NotImplemented, "#{self.class.name} must implement #{__method__}"
+  end
 
-    # Should return the hash of job arguments belonging to the most recently enqueued job
-    def job_args
-      raise NotImplemented, "#{self.class.name} must implement #{__method__}"
-    end
+  # Should return the hash of job arguments belonging to the most recently enqueued job
+  def job_args
+    raise NotImplemented, "#{self.class.name} must implement #{__method__}"
+  end
 
-    # Should return a String matching the name of the error class of the most recently failed job
-    def failed_job_error_class_name
-      raise NotImplemented, "#{self.class.name} must implement #{__method__}"
-    end
+  # Should return a String matching the name of the error class of the most recently failed job
+  def failed_job_error_class_name
+    raise NotImplemented, "#{self.class.name} must implement #{__method__}"
   end
 end
diff --git a/test/integration/resque_test.rb b/test/integration/resque_test.rb
index 5881d489..3545fa09 100644
--- a/test/integration/resque_test.rb
+++ b/test/integration/resque_test.rb
@@ -17,7 +17,13 @@ def queue_adapter
   def start_worker_and_wait
     pid = nil
     Dir.chdir("test/support/resque") do
-      pid = spawn(resque_env, "bundle exec rake resque:work")
+      pid = spawn(
+        resque_env,
+        "bundle exec rake resque:work",
+        in: "/dev/null",
+        out: "/dev/null",
+        err: "/dev/null",
+      )
     end
   ensure
     Process.wait(pid) if pid
diff --git a/test/integration/sidekiq_test.rb b/test/integration/sidekiq_test.rb
index ca0f0d18..c854b864 100644
--- a/test/integration/sidekiq_test.rb
+++ b/test/integration/sidekiq_test.rb
@@ -16,7 +16,12 @@ def queue_adapter
   end
 
   def start_worker_and_wait
-    pid = spawn("bundle exec sidekiq -r ./test/support/sidekiq/init.rb -c 1")
+    pid = spawn(
+      "bundle exec sidekiq -r ./test/support/sidekiq/init.rb -c 1",
+      in: "/dev/null",
+      out: "/dev/null",
+      err: "/dev/null",
+    )
   ensure
     Process.wait(pid)
   end
diff --git a/test/support/active_job_5_2_queue_adapters_test_adapter_compatibility_extension.rb b/test/support/active_job_5_2_queue_adapters_test_adapter_compatibility_extension.rb
new file mode 100644
index 00000000..3d463794
--- /dev/null
+++ b/test/support/active_job_5_2_queue_adapters_test_adapter_compatibility_extension.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+active_job_5_2_still_supported = Gem
+  .loaded_specs["job-iteration"]
+  .dependencies.find { |gem| gem.name == "activejob" }
+  .requirement.satisfied_by?(Gem::Version.new("5.2"))
+
+raise <<~MSG unless active_job_5_2_still_supported
+  Now that support for Active Job 5.2 has been dropped, this patch is no longer required.
+  You should:
+    - Delete this file (`#{Pathname.new(__FILE__).relative_path_from(File.join(__dir__, "../.."))}`)
+    - Remove the corresponding `require_relative` from `test/test_helper.rb`
+MSG
+
+# Nothing to do if we're using Active Job 6.0 or later
+return if Gem.loaded_specs.fetch("activejob").version >= Gem::Version.new("6.0")
+
+module JobIteration
+  # This module backports the 6.0 implementation of ActiveJob::QueueAdapters::TestAdapter#job_to_hash,
+  # which includes the serialized job, plus the fields included in 5.2's version.
+  # Without this, ActiveJob's deserialization fails when using the TestAdapter, and our tests erroneously fail.
+  module ActiveJob52QueueAdaptersTestAdapterCompatibilityExtension
+    private
+
+    def job_to_hash(job, extras = {})
+      job.serialize.tap do |job_data|
+        job_data[:job] = job.class
+        job_data[:args] = job_data.fetch("arguments")
+        job_data[:queue] = job_data.fetch("queue_name")
+      end.merge(extras)
+    end
+  end
+end
+
+ActiveJob::QueueAdapters::TestAdapter.prepend(JobIteration::ActiveJob52QueueAdaptersTestAdapterCompatibilityExtension)
diff --git a/test/support/jobs.rb b/test/support/jobs.rb
index d56a808e..e38f96f9 100644
--- a/test/support/jobs.rb
+++ b/test/support/jobs.rb
@@ -11,7 +11,7 @@ def each_iteration(omg)
     if omg == 0 || omg == 2
       Process.kill("TERM", Process.pid)
     end
-    sleep(1)
+    sleep(0.01)
   end
 end
 
diff --git a/test/support/sidekiq/init.rb b/test/support/sidekiq/init.rb
index 4f930536..fa2d4d35 100644
--- a/test/support/sidekiq/init.rb
+++ b/test/support/sidekiq/init.rb
@@ -11,6 +11,7 @@
 redis_url = ENV.fetch("REDIS_URL") { "redis://localhost:6379/0" }
 
 Sidekiq.configure_server do |config|
+  config.logger = nil
   config.redis = { url: redis_url }
 end
 
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 01ef131b..f05bf268 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -16,30 +16,12 @@
 require "pry"
 require "mocha/minitest"
 
+require_relative "support/active_job_5_2_queue_adapters_test_adapter_compatibility_extension"
+
 GlobalID.app = "iteration"
 ActiveRecord::Base.include(GlobalID::Identification) # https://github.com/rails/globalid/blob/main/lib/global_id/railtie.rb
 
-module ActiveJob
-  module QueueAdapters
-    class IterationTestAdapter
-      attr_writer(:enqueued_jobs)
-
-      def enqueued_jobs
-        @enqueued_jobs ||= []
-      end
-
-      def enqueue(job)
-        enqueued_jobs << job.serialize
-      end
-
-      def enqueue_at(job, timestamp)
-        enqueued_jobs << job.serialize.merge("retry_at" => timestamp)
-      end
-    end
-  end
-end
-
-ActiveJob::Base.queue_adapter = :iteration_test
+ActiveJob::Base.queue_adapter = :test
 
 class Product < ActiveRecord::Base
   has_many :comments
@@ -81,28 +63,31 @@ class Order < ActiveRecord::Base
 Resque.redis = Redis.current
 
 Sidekiq.configure_client do |config|
+  config.logger = nil
   config.redis = { url: redis_url }
 end
 
-ActiveRecord::Schema.define do
-  create_table(:products, force: true) do |t|
-    t.string(:name)
-    t.timestamps
-  end
+ActiveRecord::Migration.suppress_messages do
+  ActiveRecord::Schema.define do
+    create_table(:products, force: true) do |t|
+      t.string(:name)
+      t.timestamps
+    end
 
-  create_table(:comments, force: true) do |t|
-    t.string(:content)
-    t.belongs_to(:product)
-  end
+    create_table(:comments, force: true) do |t|
+      t.string(:content)
+      t.belongs_to(:product)
+    end
 
-  create_table(:travel_routes, force: true, primary_key: [:origin, :destination]) do |t|
-    t.string(:destination)
-    t.string(:origin)
-  end
+    create_table(:travel_routes, force: true, primary_key: [:origin, :destination]) do |t|
+      t.string(:destination)
+      t.string(:origin)
+    end
 
-  create_table(:orders, force: true) do |t|
-    t.integer(:shop_id)
-    t.string(:name)
+    create_table(:orders, force: true) do |t|
+      t.integer(:shop_id)
+      t.string(:name)
+    end
   end
 end
 
@@ -124,6 +109,7 @@ def assert_logged(message)
 end
 
 JobIteration.logger = Logger.new(IO::NULL)
+ActiveJob::Base.logger = Logger.new(IO::NULL)
 
 module ActiveSupport
   class TestCase
diff --git a/test/unit/active_job_iteration_test.rb b/test/unit/active_job_iteration_test.rb
index 07028312..cb9f7917 100644
--- a/test/unit/active_job_iteration_test.rb
+++ b/test/unit/active_job_iteration_test.rb
@@ -760,7 +760,7 @@ def test_interrupted_job_uses_default_retry_backoff
           ActiveRecordIterationJob.perform_now
 
           job = ActiveJob::Base.queue_adapter.enqueued_jobs.first
-          assert_equal(15.seconds.from_now.to_f, job.fetch("retry_at"))
+          assert_equal(15.seconds.from_now.to_f, job.fetch(:at))
         end
       end
     end
diff --git a/test/unit/throttle_enumerator_test.rb b/test/unit/throttle_enumerator_test.rb
index 28eabec8..e47727d0 100644
--- a/test/unit/throttle_enumerator_test.rb
+++ b/test/unit/throttle_enumerator_test.rb
@@ -117,7 +117,7 @@ def each_iteration(_record, _params); end
           IterationThrottleJob.perform_now({})
 
           job = ActiveJob::Base.queue_adapter.enqueued_jobs.first
-          assert_equal(30.seconds.from_now.to_f, job.fetch("retry_at"))
+          assert_equal(30.seconds.from_now.to_f, job.fetch(:at))
         end
       end
     end