Hides Triggers if integration only has one event

Removes confusing/unnecessary checkboxes when trying to configure an
integration. If there is only one supported event we don't need to
allow these to be individually disabled since the integration can be
disabled instead.

E.g. Project Integrations for GitHub, Bugzilla, Asana, Pipeline emails and Gemnasium

Allows integrations to override which triggers are configurable

app/models/service.rb

@@ -129,6 +129,17 @@ class Service < ActiveRecord::Base
     fields
   end
 
+  def configurable_events
+    events = self.class.supported_events
+
+    # No need to disable individual triggers when there is only one
+    if events.count == 1
+      []
+    else
+      events
+    end
+  end
+
   def supported_events
     self.class.supported_events
   end

app/views/shared/_service_settings.html.haml

@@ -13,12 +13,12 @@
       .col-sm-10
         = form.check_box :active, disabled: disable_fields_service?(@service)
 
-  - if @service.supported_events.present?
+  - if @service.configurable_events.present?
     .form-group
       = form.label :url, "Trigger", class: 'control-label'
 
       .col-sm-10
-        - @service.supported_events.each do |event|
+        - @service.configurable_events.each do |event|
           %div
             = form.check_box service_event_field_name(event), class: 'pull-left'
             .prepend-left-20

changelogs/unreleased/ce-jej-integrations-can-hide-trigger-checkboxes.yml

+---
+title: Avoid showing unnecessary Trigger checkboxes for project Integrations with
+  only one event
+merge_request: 17607
+author:
+type: changed

spec/features/projects/services/disable_triggers_spec.rb

+require 'spec_helper'
+
+describe 'Disable individual triggers' do
+  let(:project) { create(:project) }
+  let(:user) { project.owner }
+  let(:checkbox_selector) { 'input[type=checkbox][id$=_events]' }
+
+  before do
+    sign_in(user)
+
+    visit(project_settings_integrations_path(project))
+
+    click_link(service_name)
+  end
+
+  context 'service has multiple supported events' do
+    let(:service_name) { 'HipChat' }
+
+    it 'shows trigger checkboxes' do
+      event_count = HipchatService.supported_events.count
+
+      expect(page).to have_content "Trigger"
+      expect(page).to have_css(checkbox_selector, count: event_count)
+    end
+  end
+
+  context 'services only has one supported event' do
+    let(:service_name) { 'Asana' }
+
+    it "doesn't show unnecessary Trigger checkboxes" do
+      expect(page).not_to have_content "Trigger"
+      expect(page).not_to have_css(checkbox_selector)
+    end
+  end
+end