Perform email jobs in #assert_emails

Perform enqueued delivery jobs in #assert_emails and #assert_no_emails.

actionmailer/lib/action_mailer/test_helper.rb

@@ -14,7 +14,7 @@ module ActionMailer
     #     assert_emails 0
     #     ContactMailer.welcome.deliver_now
     #     assert_emails 1
-    #     ContactMailer.welcome.deliver_now
+    #     ContactMailer.welcome.deliver_later
     #     assert_emails 2
     #   end
     #
@@ -28,17 +28,19 @@ module ActionMailer
     #
     #     assert_emails 2 do
     #       ContactMailer.welcome.deliver_now
-    #       ContactMailer.welcome.deliver_now
+    #       ContactMailer.welcome.deliver_later
     #     end
     #   end
-    def assert_emails(number)
+    def assert_emails(number, &block)
       if block_given?
         original_count = ActionMailer::Base.deliveries.size
-        yield
+        perform_enqueued_jobs(only: [ActionMailer::DeliveryJob, ActionMailer::Parameterized::DeliveryJob], &block)
         new_count = ActionMailer::Base.deliveries.size
         assert_equal number, new_count - original_count, "#{number} emails expected, but #{new_count - original_count} were sent"
       else
-        assert_equal number, ActionMailer::Base.deliveries.size
+        perform_enqueued_jobs(only: [ActionMailer::DeliveryJob, ActionMailer::Parameterized::DeliveryJob]) do
+          assert_equal number, ActionMailer::Base.deliveries.size
+        end
       end
     end
 

actionmailer/test/test_helper_test.rb

@@ -69,6 +69,16 @@ class TestHelperMailerTest < ActionMailer::TestCase
     end
   end
 
+  def test_assert_emails_with_enqueued_emails
+    assert_nothing_raised do
+      assert_emails 1 do
+        silence_stream($stdout) do
+          TestHelperMailer.test.deliver_later
+        end
+      end
+    end
+  end
+
   def test_repeated_assert_emails_calls
     assert_nothing_raised do
       assert_emails 1 do
@@ -105,6 +115,18 @@ class TestHelperMailerTest < ActionMailer::TestCase
     end
   end
 
+  def test_assert_no_emails_with_enqueued_emails
+    error = assert_raise ActiveSupport::TestCase::Assertion do
+      assert_no_emails do
+        silence_stream($stdout) do
+          TestHelperMailer.test.deliver_later
+        end
+      end
+    end
+
+    assert_match(/0 .* but 1/, error.message)
+  end
+
   def test_assert_emails_too_few_sent
     error = assert_raise ActiveSupport::TestCase::Assertion do
       assert_emails 2 do