add support for recognizing mailer many jobs:

lib/rspec/rails/feature_check.rb

@@ -38,6 +38,14 @@ def has_action_mailer_show_preview?
           ::ActionMailer::Base.respond_to?(:show_previews=)
       end
 
+      def has_action_mailer_parameterized?
+        has_action_mailer? && defined?(::ActionMailer::Parameterized)
+      end
+
+      def has_action_mailer_unified_delivery?
+        has_action_mailer? && defined?(::ActionMailer::MailDeliveryJob)
+      end
+
       def has_action_mailbox?
         defined?(::ActionMailbox)
       end

lib/rspec/rails/matchers/active_job.rb

@@ -97,7 +97,7 @@ def supports_block_expectations?
 
           def check(jobs)
             @matching_jobs, @unmatching_jobs = jobs.partition do |job|
-              if arguments_match?(job) && other_attributes_match?(job)
+              if job_match?(job) && arguments_match?(job) && other_attributes_match?(job)
                 args = deserialize_arguments(job)
                 @block.call(*args)
                 true
@@ -134,6 +134,10 @@ def base_job_message(job)
             end
           end
 
+          def job_match?(job)
+            @job ? @job == job[:job] : true
+          end
+
           def arguments_match?(job)
             if @args.any?
               deserialized_args = deserialize_arguments(job)
@@ -151,7 +155,6 @@ def serialized_attributes
             {}.tap do |attributes|
               attributes[:at]    = serialized_at if @at
               attributes[:queue] = @queue if @queue
-              attributes[:job]   = @job if @job
             end
           end
 

lib/rspec/rails/matchers/have_enqueued_mail.rb

@@ -14,11 +14,10 @@ class HaveEnqueuedMail < ActiveJob::HaveEnqueuedJob
         include RSpec::Mocks::ExampleMethods
 
         def initialize(mailer_class, method_name)
-          super(mailer_job)
+          super(nil)
           @mailer_class = mailer_class
           @method_name = method_name
           @mail_args = []
-          @args = mailer_args
         end
 
         def description
@@ -27,7 +26,7 @@ def description
 
         def with(*args, &block)
           @mail_args = args
-          block.nil? ? super(*mailer_args) : super(*mailer_args, &yield_mail_args(block))
+          block.nil? ? super : super(&yield_mail_args(block))
         end
 
         def matches?(block)
@@ -67,24 +66,23 @@ def mailer_class_name
           @mailer_class ? @mailer_class.name : 'ActionMailer::Base'
         end
 
-        def mailer_args
-          if @mail_args.any?
-            base_mailer_args + @mail_args
-          elsif @mailer_class && @method_name
-            mailer_method_arity = @mailer_class.instance_method(@method_name).arity
+        def job_match?(job)
+          legacy_mail?(job) || parameterized_mail?(job) || unified_mail?(job)
+        end
 
-            number_of_args = if mailer_method_arity < 0
-                               (mailer_method_arity + 1).abs
-                             else
-                               mailer_method_arity
-                             end
+        def arguments_match?(job)
+          @args =
+            if @mail_args.any?
+              base_mailer_args + @mail_args
+            elsif @mailer_class && @method_name
+              base_mailer_args + [any_args]
+            elsif @mailer_class
+              [mailer_class_name, any_args]
+            else
+              []
+            end
 
-            base_mailer_args + Array.new(number_of_args) { anything }
-          elsif @mailer_class
-            [mailer_class_name, any_args]
-          else
-            []
-          end
+          super(job)
         end
 
         def base_mailer_args
@@ -103,7 +101,7 @@ def check_active_job_adapter
 
         def unmatching_mail_jobs
           @unmatching_jobs.select do |job|
-            job[:job] == mailer_job
+            job_match?(job)
           end
         end
 
@@ -129,8 +127,16 @@ def mail_job_message(job)
           "#{mailer_method} #{msg_parts.join(', ')}".strip
         end
 
-        def mailer_job
-          ActionMailer::DeliveryJob
+        def legacy_mail?(job)
+          job[:job] == ActionMailer::DeliveryJob
+        end
+
+        def parameterized_mail?(job)
+          RSpec::Rails::FeatureCheck.has_action_mailer_parameterized? && job[:job] == ActionMailer::Parameterized::DeliveryJob
+        end
+
+        def unified_mail?(job)
+          RSpec::Rails::FeatureCheck.has_action_mailer_unified_delivery? && job[:job] == ActionMailer::MailDeliveryJob
         end
       end
       # @api public

spec/rspec/rails/matchers/have_enqueued_mail_spec.rb

@@ -14,6 +14,15 @@ def email_with_optional_args(required_arg, optional_arg = nil); end
   class AnotherTestMailer < ActionMailer::Base
     def test_email; end
   end
+
+  if RSpec::Rails::FeatureCheck.has_action_mailer_unified_delivery?
+    class UnifiedMailer < ActionMailer::Base
+      self.delivery_job = ActionMailer::MailDeliveryJob
+
+      def test_email; end
+      def email_with_args(arg1, arg2); end
+    end
+  end
 end
 
 RSpec.describe "HaveEnqueuedMail matchers", :skip => !RSpec::Rails::FeatureCheck.has_active_job? do
@@ -327,5 +336,59 @@ def self.name; "NonMailerJob"; end
         expect(second_arg).to eq('noon')
       }
     end
+
+    context 'when parameterized', :skip => !RSpec::Rails::FeatureCheck.has_action_mailer_parameterized? do
+      it "passes when mailer is parameterized" do
+        expect {
+          TestMailer.with('foo' => 'bar').test_email.deliver_later
+        }.to have_enqueued_mail(TestMailer, :test_email)
+      end
+
+      it "passes when mixing parameterized and non-parameterized emails" do
+        expect {
+          TestMailer.with('foo' => 'bar').test_email.deliver_later
+          TestMailer.email_with_args(1, 2).deliver_later
+        }.to have_enqueued_mail(TestMailer, :test_email).and have_enqueued_mail(TestMailer, :email_with_args)
+      end
+
+      it "passes with provided argument matchers" do
+        expect {
+          TestMailer.with('foo' => 'bar').test_email.deliver_later
+        }.to have_enqueued_mail(TestMailer, :test_email).with('foo' => 'bar')
+
+        expect {
+          TestMailer.with('foo' => 'bar').email_with_args(1, 2).deliver_later
+        }.to have_enqueued_mail(TestMailer, :email_with_args).with({ 'foo' => 'bar' }, 1, 2)
+      end
+    end
+
+    context 'mailer job is unified', :skip => !RSpec::Rails::FeatureCheck.has_action_mailer_unified_delivery? do
+      it "passes when mailer is parameterized" do
+        expect {
+          UnifiedMailer.with('foo' => 'bar').test_email.deliver_later
+        }.to have_enqueued_mail(UnifiedMailer, :test_email)
+      end
+
+      it "passes when mixing parameterized and non-parameterized emails" do
+        expect {
+          UnifiedMailer.with('foo' => 'bar').test_email.deliver_later
+          UnifiedMailer.email_with_args(1, 2).deliver_later
+        }.to have_enqueued_mail(UnifiedMailer, :test_email).and have_enqueued_mail(UnifiedMailer, :email_with_args)
+      end
+
+      it "passes with provided argument matchers" do
+        expect {
+          UnifiedMailer.with('foo' => 'bar').test_email.deliver_later
+        }.to have_enqueued_mail(UnifiedMailer, :test_email).with(
+          a_hash_including(:params => { 'foo' => 'bar' })
+        )
+
+        expect {
+          UnifiedMailer.with('foo' => 'bar').email_with_args(1, 2).deliver_later
+        }.to have_enqueued_mail(UnifiedMailer, :email_with_args).with(
+          a_hash_including(:params => { 'foo' => 'bar' }, :args => [1, 2])
+        )
+      end
+    end
   end
 end