Ability to test activejobs with relative delay

`assert_enqueued_with` and `assert_performed_with` were not able to
properly test jobs with relative delay. `:at` option was asserted for
equality and test will always fail cause small fraction of time will
pass between job call and assertion.

This commit fixes that by droping microseconds from `:at` argument
assertions.

activejob/CHANGELOG.md

@@ -1,3 +1,6 @@
+*   `assert_enqueued_with` and `assert_performed_with` can now test jobs with relative delay.
+
+    *Vlado Cingel*
 
 
 Please check [6-0-stable](https://github.com/rails/rails/blob/6-0-stable/activejob/CHANGELOG.md) for previous changes.

activejob/lib/active_job/test_helper.rb

@@ -630,7 +630,7 @@ module ActiveJob
 
       def prepare_args_for_assertion(args)
         args.dup.tap do |arguments|
-          arguments[:at] = arguments[:at].to_f if arguments[:at]
+          arguments[:at] = round_time_arguments(arguments[:at]) if arguments[:at]
           arguments[:args] = round_time_arguments(arguments[:args]) if arguments[:args]
         end
       end
@@ -650,6 +650,7 @@ module ActiveJob
 
       def deserialize_args_for_assertion(job)
         job.dup.tap do |new_job|
+          new_job[:at] = round_time_arguments(Time.at(new_job[:at])) if new_job[:at]
           new_job[:args] = ActiveJob::Arguments.deserialize(new_job[:args]) if new_job[:args]
         end
       end

activejob/test/cases/test_helper_test.rb

@@ -621,6 +621,12 @@ class EnqueuedJobsTest < ActiveJob::TestCase
     end
   end
 
+  def test_assert_enqueued_with_with_relative_at_option
+    assert_enqueued_with(job: HelloJob, at: 5.minutes.from_now) do
+      HelloJob.set(wait: 5.minutes).perform_later
+    end
+  end
+
   def test_assert_enqueued_with_with_no_block_with_at_option
     HelloJob.set(wait_until: Date.tomorrow.noon).perform_later
     assert_enqueued_with(job: HelloJob, at: Date.tomorrow.noon)
@@ -1663,6 +1669,18 @@ class PerformedJobsTest < ActiveJob::TestCase
     end
   end
 
+  def test_assert_performed_with_with_relative_at_option
+    assert_performed_with(job: HelloJob, at: 5.minutes.from_now) do
+      HelloJob.set(wait: 5.minutes).perform_later
+    end
+
+    assert_raise ActiveSupport::TestCase::Assertion do
+      assert_performed_with(job: HelloJob, at: 2.minutes.from_now) do
+        HelloJob.set(wait: 1.minute).perform_later
+      end
+    end
+  end
+
   def test_assert_performed_with_without_block_with_at_option
     HelloJob.set(wait_until: Date.tomorrow.noon).perform_later