Add participants spec

spec/views/shared/issuable/_participants.html.haml.rb

+require 'spec_helper'
+require 'nokogiri'
+
+def expect_lazy_load_image(author)
+  avatar = author.find('img')
+
+  expect(avatar[:src]).to eql?('data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==')
+  expect(avatar[:"data-src"]).to exist
+end
+
+describe 'shared/issuable/_participants.html.haml' do
+  let(:project) { create(:project) }
+  let(:participants)  { create_list(:user, 10) }
+
+  before do
+    allow(view).to receive_messages(project: project,
+                                    participants: participants)
+  end
+
+  it 'displays' do
+    render 'shared/issuable/participants'
+
+    html = Nokogiri::HTML(rendered)
+
+    authors = html.css('.participants-author')
+    p authors
+    p authors.size
+    visible_authors = authors[0..6]
+    hidden_authors = authors[7..-1]
+
+    visible_authors.each do |author|
+      expect(author).not_to have_selector('js-participants-hidden')
+      expect_lazy_load_image(author)
+    end
+
+    hidden_authors.each do |author|
+      expect(author).to have_selector('js-participants-hidden')
+      expect_lazy_load_image(author)
+    end
+  end
+end