C# – How to install NUnit for C# with NuGet Package Manager on Visual Studio 2015

I have Visual Studio 2015. I want to add NUnit's tests for C# project with NuGet Package Manager, and I want to have possibility of running tests with Visual Studio and in Visual Studio.

1. First I create new C# project:
   menu File → New → Project → Installed → Templates → Visual C# → Console Application → OK.

2. Then I install NUnit:
   menu Tools → NuGet Package Manager → Manage NuGet Packages for Solution… Then I install packages:

   • NUnit
   • NUnit.Runner
   • NUnitTestAdapter

   In the output I see:

   Successfully installed 'NUnit 3.0.0-beta-4' to Tmp.
   Successfully installed 'NUnit.Runners 2.6.4' to Tmp.
   Successfully installed 'NUnitTestAdapter 2.0.0' to Tmp.
   

3. The next step I do is adding new class with code:
   Right click on project → Add → Class → Visual C# Items → Class
   name Tests.cs → Add

   Then I use below code:

   namespace NUnit.Tests
   {
       using System;
       using NUnit.Framework;
   
       [TestFixture]
       public class Tests
       {
           [Test]
           public void t1()
           {
           }
           [Test]
           public void t2()
           {
           }
       }
   }
   

4. And finally when I press RunAll on Test Explorer I see:

   ------ Discover test started ------
   NUnit VS Adapter 2.0.0.0 discovering tests is started
   Attempt to load assembly with unsupported test framework in  C:\Users\Grzegorz\Desktop\Tmp\Tmp\bin\Debug\Tmp.exe
   NUnit VS Adapter 2.0.0.0 discovering test is finished
   ========== Discover test finished: 0 found (0:00:00,0720041) ==========
   
   No tests are being discovered.
   

The strange thing is that I found no tutorial when anybody uses NuGet to install NUnit in Visual Studio 2015 and run tests in Visual Studio.