Add discord spec to check the embed parameters

spec/models/project_services/discord_service_spec.rb

@@ -31,6 +31,24 @@ describe DiscordService do
       WebMock.stub_request(:post, webhook_url)
     end
 
+    it 'uses the right embed parameters' do
+      builder = Discordrb::Webhooks::Builder.new
+
+      allow_next_instance_of(Discordrb::Webhooks::Client) do |client|
+        allow(client).to receive(:execute).and_yield(builder)
+      end
+
+      subject.execute(sample_data)
+
+      expect(builder.to_json_hash[:embeds].first).to include(
+        description: start_with("#{user.name} pushed to branch [master](http://localhost/#{project.namespace.path}/#{project.path}/commits/master) of"),
+        author: hash_including(
+          icon_url: start_with('https://www.gravatar.com/avatar/'),
+          name: user.name
+        )
+      )
+    end
+
     context 'DNS rebind to local address' do
       before do
         stub_dns(webhook_url, ip_address: '192.168.2.120')