Add frontend fixture for releases

This commit adds a frontend fixture for a single release object fetched
from the REST API.

spec/frontend/fixtures/releases.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Releases (JavaScript fixtures)' do
+  include JavaScriptFixturesHelpers
+
+  let_it_be(:admin) { create(:admin) }
+  let_it_be(:project) { create(:project, :repository, path: 'releases-project') }
+
+  let_it_be(:milestone_12_3) do
+    create(:milestone,
+           project: project,
+           title: '12.3',
+           start_date: Time.zone.parse('2018-12-10'),
+           due_date: Time.zone.parse('2019-01-10'))
+  end
+
+  let_it_be(:milestone_12_4) do
+    create(:milestone,
+           project: project,
+           title: '12.4',
+           start_date: Time.zone.parse('2019-01-10'),
+           due_date: Time.zone.parse('2019-02-10'))
+  end
+
+  let_it_be(:open_issues_12_3) do
+    create_list(:issue, 2, milestone: milestone_12_3, project: project)
+  end
+
+  let_it_be(:closed_issues_12_3) do
+    create_list(:issue, 3, :closed, milestone: milestone_12_3, project: project)
+  end
+
+  let_it_be(:open_issues_12_4) do
+    create_list(:issue, 3, milestone: milestone_12_4, project: project)
+  end
+
+  let_it_be(:closed_issues_12_4) do
+    create_list(:issue, 1, :closed, milestone: milestone_12_4, project: project)
+  end
+
+  let_it_be(:release) do
+    create(:release,
+           :with_evidence,
+           milestones: [milestone_12_3, milestone_12_4],
+           project: project,
+           tag: 'v1.1',
+           name: 'The first release',
+           description: 'Best. Release. **Ever.** :rocket:',
+           created_at: Time.zone.parse('2018-12-3'),
+           released_at: Time.zone.parse('2018-12-10'))
+  end
+
+  let_it_be(:other_link) do
+    create(:release_link,
+           release: release,
+           name: 'linux-amd64 binaries',
+           filepath: '/binaries/linux-amd64',
+           url: 'https://downloads.example.com/bin/gitlab-linux-amd64')
+  end
+
+  let_it_be(:runbook_link) do
+    create(:release_link,
+           release: release,
+           name: 'Runbook',
+           url: 'https://example.com/runbook',
+           link_type: :runbook)
+  end
+
+  before(:all) do
+    clean_frontend_fixtures('api/releases/')
+  end
+
+  after(:all) do
+    remove_repository(project)
+  end
+
+  describe API::Releases, '(JavaScript fixtures)', type: :request do
+    include ApiHelpers
+
+    it 'api/releases/release.json' do
+      get api("/projects/#{project.id}/releases/#{release.tag}", admin)
+
+      expect(response).to be_successful
+    end
+  end
+end