why are unit tests greyed out in visual studio 2015 for sql server project?

I have created and added a sql server project into my visual studio 2015 c# solution.

I would like to do unit testing for my stored procedures. After right clicking on one of the procedures, it is showing create unit test as greyed out:

I did get the most recent SSDT update.

Why is the create unit test option greyed out?

Here is the information about my visual studio version:

Microsoft Visual Studio Professional 2015 Version 14.0.24720.00 Update 1 Microsoft .NET Framework Version 4.6.01055

Installed Version: Professional

Visual Basic 2015 Microsoft Visual Basic 2015

Visual C# 2015 Microsoft Visual C# 2015

Visual C++ 2015 Microsoft Visual C++ 2015

Visual F# 2015 Microsoft Visual F# 2015

Application Insights Tools for Visual Studio Package 1.0 Application Insights Tools for Visual Studio

ASP.NET and Web Tools 2015.1 (Beta8) 14.1.11106.0 ASP.NET and Web Tools 2015.1 (Beta8)

ASP.NET Web Frameworks and Tools 2012.2 4.1.41102.0 For additional information, visit http://ift.tt/1gxd1tX

ASP.NET Web Frameworks and Tools 2013 5.2.30624.0 For additional information, visit http://www.asp.net/

Common Azure Tools 1.5 Provides common services for use by Azure Mobile Services and Microsoft Azure Tools.

JetBrains ReSharper Ultimate 10.0.2 Build 104.0.20151218.120627 JetBrains ReSharper Ultimate package for Microsoft Visual Studio. For more information about ReSharper Ultimate, visit http://ift.tt/14GJ6oQ. Copyright © 2016 JetBrains, Inc.

Microsoft Azure Mobile Services Tools 1.4 Microsoft Azure Mobile Services Tools

NuGet Package Manager 3.3.0 NuGet Package Manager in Visual Studio. For more information about NuGet, visit http://docs.nuget.org/.

PreEmptive Analytics Visualizer 1.2 Microsoft Visual Studio extension to visualize aggregated summaries from the PreEmptive Analytics product.

Python Tools for Visual Studio 2.2.31124.00 Python Tools for Visual Studio provides IntelliSense, projects, templates, Interactive windows, and other support for Python developers.

Python Tools for Visual Studio - Django Integration 2.2.31124.00 Provides templates and integration for the Django web framework.

Python Tools for Visual Studio - Profiling Support 2.2.31124.00 Profiling support for Python projects.

SlowCheetah - XML config transforms 1.0 This package enables you to transform your app.config or any other XML file based on the build configuration. It also adds additional tooling to help you create XML transforms.

SQL Server Data Tools 14.0.50730.0 Microsoft SQL Server Data Tools

TypeScript 1.7.6.0 TypeScript for Microsoft Visual Studio