SF_10.1, SF_10.2, SF_11.0, SF_11.1, SF_11.2, SF_12.0, SF_12.1, SF_12.2, SF_13.0, SF_13.1, SF_13.2, SF_13.3, SF_14.0, SF_14.1, SF_14.2, SF_14.3 - https://docs.sitefinity.com/application-status-page-in-continuous-integration-scenarios

SitefinityStatusHelper.cs

using Microsoft.Http;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Threading;
using System.Web;

namespace CiUtilities
{
    public static class SitefinityStatusHelper
    {
        /// <summary>
        /// Waits for sitefintiy to start.
        /// </summary>
        /// <param name="testingInstanceUrl">The testing Sitefinity instance url.</param>
        /// <param name="totalWaitSeconds">the maximum wait time in seconds.</param>
        public static void WaitForSitefinityToStart(string testingInstanceUrl, double totalWaitSeconds)
        {
            // While /appstatus service is responding, Sitefinity is either in Initialize or Upgrade state.
            // Since Sitefinity Bootstrap is running on a different than main thread, getting of the tests is postoned until Sitefinity is up and running
            DateTime startTime = DateTime.UtcNow;
            TimeSpan elapsedTime = new TimeSpan();
            HttpResponseMessage response;
            HttpClient client = new HttpClient();

            do
            {                
                response = client.Get(testingInstanceUrl + "/appstatus");
                Thread.Sleep(1000);
                elapsedTime = DateTime.UtcNow.Subtract(startTime);

            } while (response.StatusCode == HttpStatusCode.OK && elapsedTime.TotalSeconds < totalWaitSeconds);

            if (elapsedTime.TotalSeconds > totalWaitSeconds)
            {
                throw new Exception("Sitefinity did not start in less than " + totalWaitSeconds / 60 + " minultes.");
            }
        }
    }
}