Add specs for ServiceEventEntity

- Move slack_service factory from EE to main code
- Minor refactoring around entity code

app/serializers/service_event_entity.rb

@@ -7,9 +7,7 @@ class ServiceEventEntity < Grape::Entity
     event
   end
 
-  expose :name do |event|
-    event_field_name
-  end
+  expose :event_field_name, as: :name
 
   expose :value do |event|
     service[event_field_name]
@@ -37,7 +35,7 @@ class ServiceEventEntity < Grape::Entity
   end
 
   def event_field
-    service.event_field(event)
+    @event_field ||= service.event_field(event)
   end
 
   def service

ee/spec/factories/services.rb

@@ -14,13 +14,6 @@ FactoryBot.define do
     type { 'GithubService' }
   end
 
-  factory :slack_service do
-    project
-    active { true }
-    webhook { 'https://slack.service.url' }
-    type { 'SlackService' }
-  end
-
   factory :slack_slash_commands_service do
     project
     active { true }

spec/factories/services.rb

@@ -158,6 +158,13 @@ FactoryBot.define do
     token { 'test_token' }
   end
 
+  factory :slack_service do
+    project
+    active { true }
+    webhook { 'https://slack.service.url' }
+    type { 'SlackService' }
+  end
+
   # this is for testing storing values inside properties, which is deprecated and will be removed in
   # https://gitlab.com/gitlab-org/gitlab/issues/29404
   trait :without_properties_callback do

spec/serializers/service_event_entity_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe ServiceEventEntity do
+  let(:request) { double('request') }
+
+  subject { described_class.new(event, request: request, service: service).as_json }
+
+  before do
+    allow(request).to receive(:service).and_return(service)
+  end
+
+  describe '#as_json' do
+    context 'service without fields' do
+      let(:service) { create(:emails_on_push_service, push_events: true) }
+      let(:event) { 'push' }
+
+      it 'exposes correct attributes' do
+        expect(subject[:description]).to eq('Event will be triggered by a push to the repository')
+        expect(subject[:name]).to eq('push_events')
+        expect(subject[:title]).to eq('push')
+        expect(subject[:value]).to be(true)
+      end
+    end
+
+    context 'service with fields' do
+      let(:service) { create(:slack_service, note_events: false, note_channel: 'note-channel') }
+      let(:event) { 'note' }
+
+      it 'exposes correct attributes' do
+        expect(subject[:description]).to eq('Event will be triggered when someone adds a comment')
+        expect(subject[:name]).to eq('note_events')
+        expect(subject[:title]).to eq('note')
+        expect(subject[:value]).to eq(false)
+        expect(subject[:field][:name]).to eq('note_channel')
+        expect(subject[:field][:value]).to eq('note-channel')
+      end
+    end
+  end
+end