Question

I have built a windows service to populate a database with my email inbox every 5 minutes.

I used a class inside my windows service the class gets my emails and writes them to my database, the class has been tested and works.

All i need the windows service to do is use a timer and call the class every 5 minutes, but i have no idea whats going on as i cant even test my windows service.

Please someone tel me what to do to test, if there is a way to test, or just blink luck and pray it works lol.

Also do u have to uninstall and re-install every time you want to test the service or is there an update service option? Please answer this i’m really interested even tho its not my main question.

This is my windows service, if u can point out any errors that would be amazing since i cant test for them. I think my timer might be wrong if some one could look at it?

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Linq;
using System.ServiceProcess;
using System.Text;
using System.Timers;

namespace EmailWindowsService
{
    public partial class MyEmailService : ServiceBase
    {
        private Timer scheduleTimer1 = null;
        private DateTime lastRun;
        private bool flag;

        public MyEmailService()
        {
            InitializeComponent();
            if (!System.Diagnostics.EventLog.SourceExists("MySource"))
            {
                System.Diagnostics.EventLog.CreateEventSource(
                    "MySource", "MyNewLog");
            }
            eventLogEmail.Source = "MySource";
            eventLogEmail.Log = "MyNewLog";

            scheduleTimer1 = new Timer();
            scheduleTimer1.Interval = 5 * 60 * 1000;
            scheduleTimer1.Elapsed += new ElapsedEventHandler(scheduleTimer_Elapsed);
        }

        protected override void OnStart(string[] args)
        {
            flag = true;
            lastRun = DateTime.Now;
            scheduleTimer.Start();
            eventLogEmail.WriteEntry("Started");
        }

        protected override void OnStop()
        {
            scheduleTimer.Stop();
            eventLogEmail.WriteEntry("Stopped");
        }
        protected override void OnPause()
        {
            scheduleTimer.Stop();
            eventLogEmail.WriteEntry("Paused");
        }
        protected override void OnContinue()
        {
            scheduleTimer.Start(); ;
            eventLogEmail.WriteEntry("Continuing");
        }
        protected override void OnShutdown()
        {
            scheduleTimer.Stop();
            eventLogEmail.WriteEntry("ShutDowned");
        }

        protected void scheduleTimer_Elapsed(object sender, ElapsedEventArgs e)
        {
            RetriveEmailClass Emails = new RetriveEmailClass();
            if (flag == true)
            {

                eventLogEmail.WriteEntry("In getting Email Method");
                Emails.ServiceEmailMethod();
                lastRun = DateTime.Now;
                flag = false;
            }
            else if (flag == false)
            {
                if (lastRun.Date < DateTime.Now.Date)
                {
                    Emails.ServiceEmailMethod();
                    eventLogEmail.WriteEntry("In getting Email Method");
                }
            }
        }
        }


    }

Answer 1

Surely you can test it. All you need is

1. start up the service
2. observe that it triggers the expected call after 5 minutes
3. (observe that it triggers the expected call every 5 minutes for a couple more times)

You can test this manually, or (preferably) create/use an automated test harness which allows you to test repeatedly and reliably, as many times as you want. This is possible even using a simple batch file.

To detect that the timer works correctly, you can inspect its log file. It also helps of course if you make the called class method configurable instead of hardcoding it. So you can run your automated tests using a dummy worker class which does not flood your inbox 🙂

To make it even more testable, you can extract the timing logic from your service class too, so that it becomes runnable from a regular application. Then you can test it even easier, even using a unit test framework such as NUnit. This allows you to do more thorough testing, using different timing intervals etc. And the service class itself becomes an almost empty shell whose only job is to launch and call the other classes. If you have verified that all the classes containing real program logic (i.e. all the code which can fail) is unit tested and works fine, you can have much greater confidence in that your whole app, when integrated from its smaller parts, works correctly too.

Update

Looking through your code, it seems that you don’t initialize flag anywhere, so its default value will be false. You should initialize it to true in the constructor, otherwise your email retriever won’t ever get called even if the timer fires properly.

To set the interval to 1 minute, my first guess would be

scheduleTimer1.Interval = 1 * 60 * 1000;