tests: add test that execute an ActionMailer delivery

instrumentation/action_mailer/lib/opentelemetry/instrumentation/action_mailer/railtie.rb

@@ -14,23 +14,33 @@ module ActionMailer
       class Railtie < ::Rails::Railtie
         config.after_initialize do
           ::OpenTelemetry::Instrumentation::ActiveSupport::Instrumentation.instance.install({})
+          subscribe_to_deliver
+          subscribe_to_process
+        end
 
-          config = ActionMailer::Instrumentation.instance.config
+        private
 
+        def subscribe_to_deliver
           ::OpenTelemetry::Instrumentation::ActiveSupport.subscribe(
             ActionMailer::Instrumentation.instance.tracer,
             DELIVER_SUBSCRIPTION,
             config[:notification_payload_transform],
             config[:disallowed_notification_payload_keys]
           )
+        end
 
+        def subscribe_to_process
           ::OpenTelemetry::Instrumentation::ActiveSupport.subscribe(
             ActionMailer::Instrumentation.instance.tracer,
             PROCESS_SUBSCRIPTION,
             config[:process_payload_transform],
             config[:disallowed_process_payload_keys]
           )
         end
+
+        def config
+          ActionMailer::Instrumentation.instance.config
+        end
       end
     end
   end

instrumentation/action_mailer/test/opentelemetry/instrumentation/action_mailer/subscription_test.rb

@@ -0,0 +1,148 @@
+# frozen_string_literal: true
+
+# Copyright The OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require 'test_helper'
+require 'opentelemetry-instrumentation-active_support'
+
+class Proc
+  def inspect
+    'A proc'
+  end
+end
+
+describe OpenTelemetry::Instrumentation::ActionMailer do
+  let(:exporter) { EXPORTER }
+  let(:spans) { exporter.finished_spans }
+  let(:instrumentation) { OpenTelemetry::Instrumentation::ActionMailer::Instrumentation.instance }
+
+  before do
+    exporter.reset
+  end
+
+  describe 'deliver.action_mailer' do
+    describe 'with default configuration' do
+      it 'generates a deliver span' do
+        subscribing_to_deliver do
+          TestMailer.hello_world.deliver_now
+        end
+
+        _(spans.length).must_equal(1)
+        span = spans.find { |s| s.name == 'deliver.action_mailer' }
+
+        _(span).wont_be_nil
+
+        _(span.attributes['email.x_mailer']).must_equal('TestMailer')
+        _(span.attributes['email.subject']).must_equal('Hello world')
+        _(span.attributes['email.message_id']).wont_be_empty
+      end
+    end
+
+    describe 'with custom configuration' do
+      it 'with email_address: :include' do
+        with_configuration(email_address: :include, disallowed_notification_payload_keys: []) do
+          subscribing_to_deliver do
+            TestMailer.hello_world.deliver_now
+          end
+        end
+
+        _(spans.length).must_equal(1)
+        span = spans.find { |s| s.name == 'deliver.action_mailer' }
+
+        _(span).wont_be_nil
+
+        _(span.attributes['email.x_mailer']).must_equal('TestMailer')
+        _(span.attributes['email.subject']).must_equal('Hello world')
+        _(span.attributes['email.message_id']).wont_be_empty
+        _(span.attributes['email.to.address']).must_equal(['[email protected]'])
+        _(span.attributes['email.from.address']).must_equal(['[email protected]'])
+        _(span.attributes['email.cc.address']).must_equal(['[email protected]'])
+        _(span.attributes['email.bcc.address']).must_equal(['[email protected]'])
+      end
+
+      it 'with a custom transform proc' do
+        transform = ->(payload) { payload.transform_keys(&:upcase) }
+        with_configuration(notification_payload_transform: transform) do
+          instrumentation.send(:ecs_mail_convention)
+          subscribing_to_deliver do
+            TestMailer.hello_world.deliver_now
+          end
+        end
+
+        _(spans.length).must_equal(1)
+        span = spans.find { |s| s.name == 'deliver.action_mailer' }
+
+        _(span).wont_be_nil
+
+        _(span.attributes['EMAIL.X_MAILER']).must_equal('TestMailer')
+        _(span.attributes['EMAIL.SUBJECT']).must_equal('Hello world')
+        _(span.attributes['EMAIL.MESSAGE_ID']).wont_be_empty
+      end
+    end
+  end
+
+  describe 'process.action_mailer' do
+    describe 'with default configuration' do
+      it 'generates a process span' do
+        transform = ->(payload) { payload.transform_keys(&:upcase) }
+        with_configuration(disallowed_process_payload_keys: [:ARGS], process_payload_transform: transform) do
+          subscribing_to_process do
+            TestMailer.hello_world('Hola mundo').deliver_now
+          end
+        end
+
+        _(spans.length).must_equal(1)
+        span = spans.find { |s| s.name == 'process.action_mailer' }
+
+        _(span).wont_be_nil
+
+        _(span.attributes['MAILER']).must_equal('TestMailer')
+        _(span.attributes['ACTION']).must_equal('hello_world')
+        _(span.attributes['ARGS']).must_be_nil
+      end
+    end
+
+    describe 'with custom configuration' do
+      it 'generates a process span' do
+        subscribing_to_process do
+          TestMailer.hello_world('Hola mundo').deliver_now
+        end
+
+        _(spans.length).must_equal(1)
+        span = spans.find { |s| s.name == 'process.action_mailer' }
+
+        _(span).wont_be_nil
+
+        _(span.attributes['mailer']).must_equal('TestMailer')
+        _(span.attributes['action']).must_equal('hello_world')
+        _(span.attributes['args']).must_equal(['Hola mundo'])
+      end
+    end
+  end
+
+  def with_configuration(values, &block)
+    original_config = instrumentation.instance_variable_get(:@config)
+    modified_config = original_config.merge(values)
+    instrumentation.instance_variable_set(:@config, modified_config)
+
+    yield
+
+    instrumentation.instance_variable_set(:@config, original_config)
+  end
+
+  def subscribing_to_deliver(&block)
+    subscription = OpenTelemetry::Instrumentation::ActionMailer::Railtie.instance.send(:subscribe_to_deliver)
+    yield
+  ensure
+    ActiveSupport::Notifications.unsubscribe(subscription)
+  end
+
+  def subscribing_to_process(&block)
+    subscription = OpenTelemetry::Instrumentation::ActionMailer::Railtie.instance.send(:subscribe_to_process)
+    yield
+  ensure
+    ActiveSupport::Notifications.unsubscribe(subscription)
+  end
+end

instrumentation/action_mailer/test/test_helper.rb

@@ -22,3 +22,23 @@
   c.use 'OpenTelemetry::Instrumentation::ActionMailer'
   c.add_span_processor span_processor
 end
+
+OpenTelemetry::Instrumentation::ActiveSupport::Instrumentation.instance.install({})
+OpenTelemetry::Instrumentation::ActionMailer::Instrumentation.instance.install({})
+
+ActionMailer::Base.delivery_method = :test
+
+class TestMailer < ActionMailer::Base
+  FROM = '[email protected]'
+  TO = '[email protected]'
+  CC = '[email protected]'
+  BCC = '[email protected]'
+
+  def hello_world(message = 'Hello world')
+    @message = message
+    mail from: FROM, to: TO, cc: CC, bcc: BCC do |format|
+      format.html { render inline: '<h1><%= @message %></h1>' }
+      format.text { render inline: '<%= @message %>' }
+    end
+  end
+end