What project type do you need to test a .NET standard project?

• Create a new project in Visual Studio

• Choose .NET Standard class library
• Name it Lib
• Click OK
• Open the generated class Class1 and change the code to:

using System;

namespace Lib
{
public class Class1
{
public string SayHello() => "Hello!";
}
}

Testing a .NET Standard library

.NET Standard libraries are tested with unit test projects of type .NET Framework or .NET Core projects. In this tutorial you will use a .NET Core project

• Right-click the solution and add a new project

• Choose .NET Core class library
• Name it Lib.Tests
• Click OK
• Add the following two NuGet packages:

Note: you can also add a .NET Core unit test project in Visual Studio. This will add the nuget packages automatically. For this tutorial, I think it is useful to show that a unit test project is a regular class library plus some added packages

• Add a reference from Lib.Tests to Lib.

• In the Lib.Tests project, open the generated class Class1 and change the code to:

using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;

namespace Lib.Tests
{
[TestClass]
public class TestClass1
{
[TestMethod]
public void Test1()
{
    var cl = new Class1();
    Assert.AreEqual(cl.SayHello(), "Hell!");
}
}
}

• Press CTRL-R, A to run the tests

The test will fail:

• Change the line:

Assert.AreEqual(cl.SayHello(), "Hell!");

to

Assert.AreEqual(cl.SayHello(), "Hello!");

• Test again (CTRL-R, A)

This time the test should succeed: