Warning Since version v.0.1 the RTL switched to .net 8 (Revit 2025), any further development on .net framework 4.8 (Revit 2023, 2024) is not planned.

Proof of Concept that it is possible to run and debug unit tests in Visual Studio with remote execution inside Revit.

• RevitTestFramework
• Revit.TestRunner
• xUnitRevit

There are three established solutions for unit testing in Revit space, but none of them offers integration with the IDE. This makes them good mostly for detecting regressions, which makes QA happy. We, developers, love and need unit tests for different reasons. There is no better way of writing/understanding a code, than running a small fragment of it in isolation without the need to start the whole (big (and slow)) application once again (aka green arrow development). We need as fast feedback loop as possible.

• dlls are not kept locked after conducting a unit test, which means Revit does not have to be closed down in order to recompile dlls
• full access to the exception Stack Trace with interactive links to source code
• full access to unit test Standard Output
• unit tests that are run inside Revit context can be mixed with tests that can be run outside of Revit
• unit tests are run in a special instance of Revit that does not load any addins
• tests can be run from an IDE, CLI dotnet test or as part of a build pipline

1. Add information about Revit location to .runsettings file. How to use .runsettings on Microsoft learn.

<RunSettings>
  <MSTest> 
    <AssemblyResolution>
      <Directory path="D:\Autodesk\Revit 2025\" includeSubDirectories="false"/>
    </AssemblyResolution>
  </MSTest>
</RunSettings>

2. Install nuget

https://www.nuget.org/packages/RevitTestLibrary.MSTest

3. Change test method attribute to [RevitTestMethod] and add one input parameter of type RevitContext
4. Add the RevitPath attribute [assembly: RevitPath("D:\\Autodesk\\Revit 2025\\Revit.exe")].

using System;
using System.IO;
using Autodesk.Revit.DB;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using RevitTestLibrary;

[assembly: RevitPath("D:\\Autodesk\\Revit 2025\\Revit.exe")]

namespace RevitTestLibrary.Demo.MSTestV3
{
    [TestClass]
    public class UnitTest1
    {
        [TestMethod]
        public void TestMethod_WriteLine()
        {
            Console.WriteLine("This is a standard test");
        }

        [RevitTestMethod]
        public void Revit_TestMethod_WriteLine(RevitContext context)
        {
            Console.WriteLine("This code is running inside Revit.");
        }
    }
}

The Demo project is available here: RevitTestLibrary.Demo.MSTestV3

• works only with : Revit 2025
• debugging is only available for: Visual Studio 2022
• theoretically, it can be used with any test framework, but right now only integration with MSTest v2 (>= 3.2.2) is available