.NET Tips and Tricks

Blog archive

Testing Friendly and Internal Methods

If you're doing Test Driven Development (TDD), you want to test all the methods and properties on your classes. However, some of those methods may only be intended to be used by other classes within the same class library. If so, the right thing to do is declare those methods as either Friend (Visual Basic) or internal (C#). The problem is that those methods won't be visible to your test code running in your separate test project.

The good news is that you don't have to make these methods public to test them. Instead, if you add the InternalsVisibleTo attribute to your project's Assemblyinfo file (or any source code file), you can specify that your test project has access to your project's friendly/internal members.

This example makes the internal/friendly members of the project visible to another project called MyTest:

<Assembly: System.Runtime.CompilerServices.InternalsVisibleTo("MyTest")> 

If you use the Unit Test Wizard in Visual Studio 2010, it will add this attribute to your AssemblyInfo file for you. Unfortunately, the Wizard adds the attribute at the end of the AssemblyInfo file where it won't work: the InternalsVisibleTo attribute must immediately follow any Imports or using statements at the top of the file. Visual Studio has an error correction option that will do this for you -- just click on the error block underneath the attribute to get Visual Studio to relocate it.

Posted by Peter Vogel on 05/09/2014 at 7:25 AM

comments powered by Disqus


  • Top 3 Blazor Extensions for Visual Studio Code

    Some developers prefer to create applications with Microsoft's open-source Blazor tooling from within the open-source, cross-platform Visual Studio Code editor. Here are the top tools in the VS Code Marketplace for those folk, as measured by the number of installations.

  • How to Invert a Machine Learning Matrix Using C#

    VSM Senior Technical Editor Dr. James McCaffrey, of Microsoft Research, explains why inverting a matrix -- one of the more common tasks in data science and machine learning -- is difficult and presents code that you can use as-is, or as a starting point for custom matrix inversion scenarios.

  • Microsoft Engineer: 'It's Time to Move OData to .NET 5'

    Microsoft engineer Sam Xu says "it’s time to move OData to .NET 5" and in a new blog post he shows how to do just that.

  • Microsoft Goes Virtual with Developer Education in Face of COVID-19

    Like many organizations that host developer educational events, Microsoft has gone virtual amid shelter-in-place directives and a surge in remote work stemming from the COVID-19 pandemic.

  • Microsoft Enhances Low-Code Power Apps

    Microsoft's nod to the low-code movement, Power Apps, has been enhanced with a bevy of new features, including mixed reality, canvas/model support in a new mobile app, UX improvements and more.

.NET Insight

Sign up for our newsletter.

Terms and Privacy Policy consent

I agree to this site's Privacy Policy.

Upcoming Events