Add spec for API::Github::Entities::User

Add missing spec for the GitHub API user entity.

changelogs/unreleased/233016_fix_jira_dvcs_user_avatars.yml

+---
+title: Fix broken user avatars in Jira Development Panel
+merge_request: 43563
+author:
+type: fixed

lib/api/github/entities.rb

@@ -119,7 +119,9 @@ module API
         expose :username, as: :login
         expose :user_url, as: :url
         expose :user_url, as: :html_url
-        expose :avatar_url
+        expose :avatar_url do |user|
+          user.avatar_url(only_path: false)
+        end
 
         private
 

spec/lib/api/github/entities_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe API::Github::Entities do
+  describe API::Github::Entities::User do
+    let(:user) { create(:user, username: username) }
+    let(:username) { 'name_of_user' }
+    let(:gitlab_protocol_and_host) { "#{Gitlab.config.gitlab.protocol}://#{Gitlab.config.gitlab.host}" }
+    let(:expected_user_url) { "#{gitlab_protocol_and_host}/#{username}" }
+    let(:entity) { described_class.new(user) }
+
+    subject { entity.as_json }
+
+    specify :aggregate_failure do
+      expect(subject[:id]).to eq user.id
+      expect(subject[:login]).to eq 'name_of_user'
+      expect(subject[:url]).to eq expected_user_url
+      expect(subject[:html_url]).to eq expected_user_url
+      expect(subject[:avatar_url]).to include('https://www.gravatar.com/avatar')
+    end
+
+    context 'with avatar' do
+      let(:user) { create(:user, :with_avatar, username: username) }
+
+      specify do
+        expect(subject[:avatar_url]).to include("#{gitlab_protocol_and_host}/uploads/-/system/user/avatar/")
+      end
+    end
+  end
+end