Skip to main content

NSubstitute Introduction and Why I like it

Recently I am heavily learning Test Driven Development and Domain Driven design. As you know With TDD you need to have a mocking libraries. So after doing on research on internet they are three libraries available in Microsoft.NET development world which are quite mature.

  1. Rhino Mocks
  2. NSubstitute
  3. Moq
I have gone through all of above three and then After doing research and I choose NSubstitute.

Why I Choose NSubstitute:

Following are the reasons why I have chosen NSubstitute.

  1. It is super easy to use. I don’t have to write very complex lamda expressions to mock objects.
  2. It works really fine with all framework of Test Driven Development
  3. As it is super easy to use you need to write very less code to mock objects.
  4. With other Visual Studio plugins like Resharper, Telerik Justcode its works perfectly and they are able to generate code for the same.
  5. It’s got fluent syntax and very easy to understand.
  6. It’s perfect for some one who is not mature enough for Test Driven Development.

NSubstitute - Basic Introduction:

NSubstitute is relatively a new kid on the block as compare to other two mocking libraries. It’s is a open source project hosted on github. You can find all the information related to NSubsitute via following site.

It’s also available on NuGet and You can install it via Nuget via following command.


So what’s we are waiting for Let’s create a demo application to see how it’s works. I am going to create a console application to demonstrate this.


I am also going to Add a Test Project to Run my test created with Help of NSubstitute.


Now I’m going to create person interface like below.
namespace NSubstituteBasicDemo
    public interface IPerson
        string GetFullName(string firstName,string lastName);
And same way I am going to create implementation of IPerson interface like below.
namespace NSubstituteBasicDemo
    public class Person : IPerson
        public string GetFullName(string firstName, string lastName)
            return string.Format("{0} {1}", firstName, lastName);
Now it’s time to write Test and for that we need to add nuget package for NSubstitute in test project.


Once we are done I have written following code to write a test for Person class.
using Microsoft.VisualStudio.TestTools.UnitTesting;
using NSubstitute;
using NSubstituteBasicDemo;

namespace NSubstituteTest
    public class PersonTest
        public void ToCheck_Whether_Person_FullName_Work_Or_Not()
            //Creating Substiute for person
            var person = Substitute.For<IPerson>();
            //Adding a return value
            person.GetFullName("Jalpesh", "Vadgama").Returns("Jalpesh Vadgama");

            //Asserting to check whether its fine or not
            Assert.AreEqual("Jalpesh Vadgama", person.GetFullName("Jalpesh", "Vadgama"));

Now when you run this Test it’s work perfectly.


That’s it. Hope you like it. Stay tuned for more.

You can find complete source code of this blog post at -


Popular posts from this blog

How to create Rest API(Web API) with ASP.NET Core 1.0

Recently Microsoft has released ASP.NET Core 1.0 RC2, I am getting lots of request from readers that about creating Web API. So I thought it will be a good idea to write a blog post about how to create Rest API(Web API) with ASP.NET Core 1.0.

So let’s get started via creating an ASP.NET Core 1.0 Web Application like following.

Once you click on ASP.NET Web Application, It will ask whether you need to create Web Application or Web API application. We are going to Web API so I am going to select Web API Application like following. Please note that in ASP.NET Core 1.0 there is no separate libraries or DLLs required for creating web APIs. This is just a project template.

Now once you click on OK It will create a Web API application with default values controller and program.cs.  As you know Program.cs is now starting point for the ASP.NET Core 1.0 application so It contains all the required configuration and startup items. Following is a code for that.
using System.IO; using Microsoft.Asp…

How to use migration with Entity Framework Core

Entity framework core is  the lightweight, extensible and cross-platform version of Entity Framework. Before some time, Microsoft has Released a new version of Entity Framework RC2. I have written a couple of blog post about Entity framework code first migration earlier for Entity framework 6.0. So there was a couple of request coming for writing a blog post about Entity Framework Core RC2 migration. So I thought it will be a good idea to give an overview how database migration works in Entity Framework Core RC2. This post will cover a basic scenario where we are going to create the database with existing ASP.NET Identity migration and then we are going to create a new model and have that migration applied in the database.

How to use Entity Framework Migrations: Let’s get started, To demonstrate entity framework core migrations, I am going to create a sample core web application like following.

Once we select core application it will appear the following dialog.

Now w…

Creating PDF with ASP.Net MVC and RazorPDF

Update: I have written a new blog post about better approach to create a PDF with mvc- You can find that following location.- A Better Solution to create PDF with Rotativa and ASP.NET MVC
In this post we are going to learn how we can easily create PDF from ASP.Net application with the help of Razor PDF NuGet package.

About Razor PDF:
This NuGet package is created by Al Nyveldt It internally uses ITextSharp an open source PDF convertor library. RazorPDF uses Razor View engine to create iTextXML which is in tern used to produce PDF file. You can get more information about that at below link.

Example(Creating PDF with ASP.Net MVC):
So what we are we waiting for ? Let’s create a simple example. To create example first thing we need to a create and ASP.Net MVC application.