2. In the **Extensions and Updates** dialog box, expand the **Online** category and then **Visual Studio Marketplace**. Then, choose **Tools > Testing**.
2. Select the **NUnit test adapter** and then choose **Download.**
### Add Tests
1. Create a class library project and add it to your solution.
For convinience name it like your main project and add **.Tests** as a suffix.
![alt text](images/create_class_library.png "Select Class Library")
2. Install the plug-in. In **Solution Explorer**, select the class library project, and then choose **Manage NuGet Packages** from its right-click or context menu.
![alt text](images/add_a_package.png "Add a package")
3. In the **NuGet Package Manager** window, search for and select the plug-in (NUnit), and then choose **Install**.