• Using NUnit Test Runner:
  • Download copy from NUnit Downloads.
  • Install or unpack in a folder.
• Using Test Explorer in VS [Optional]:
  • Install Visual Studio extension (Tools > Extensions and Updates): NUnit Test Adapter for Visual Studio.
• Add a reference to NUnit.Framework.dll in project (or Solution)
  • Manually: Project > References > right-click > Add References > Find path for NUnit.Framework.dll and select it.
  • Automatically: Using NuGet NUnit package (see https://www.nuget.org/packages/NUnit): Select project > right-click > Manage NuGet Packages > All > Add 'NUnit'.

Create test class in project, including all necessary test cases.

• See Example.

Create basic test class for testing unit TTools in file Acme.App.Localization\Tools.cs:

file ToolsTest.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using NUnit.Framework;
 
namespace Acme.App.Localization
{
    ///============================================================================================
    /// <summary>
    /// Class TTools
    /// </summary>
    ///============================================================================================
    [TestFixture]
    [Category("TTools")]
    class ToolsTest
    {
        [SetUp]
        public void Init()
        {
 
        }
 
        [TearDown]
        public void CleanUp()
        {
 
        }
 
        [Test, Description("Check Something Exists")]
        public void CheckSomethingExists()
        {
            Assert.AreEqual(Something, true);
        }
    }
 
}

• Using Test Explore in VS:
  • Test > Windows > Text Explorer.
  • Run tests using Unit Test Explorer > Run All.
• Using NUnit Test Runner:
  • Run Test Runner, and create new Test project (File > New Project).
  • Select assembly or application containing unit tests (Project > Add Assembly). Note: These assemblies and applications must have a reference to NUnit.Framework.dll in their individual projects.

Modern tests contain three parts:

[TestMethod]
public void GetCount_ItemCountIsZero_NoNewMessages()
{
    //Arrange
    Mailbox mailbox = new Mailbox();
 
    //Act
    var result = mailbox.GetCount(0);
 
    //Assert
    Assert.AreEqual("No new messages.", result);
}

This can be summed up as a pattern:

• Arrange: setup everything needed for the running the tested code. This includes any initialization of dependencies, mocks and data needed for the test to run.
• Act: Invoke the code under test.
• Assert: Specify the pass criteria for the test, which fails it if not met.

Source: Unit Test Patterns for .NET