How do I run NUnit in debug mode from Visual Studio?

Question

I've recently been building a test framework for a bit of C# I've been working on. I have NUnit set up and a new project within my workspace to test the component. All works well if I load up my unit tests from Nunit (v2.4), but I've got to the point where it would be really useful to run in debug mode and set some break points.

I've tried the suggestions from several guides which all suggest changing the 'Debug' properties of the test project:

Start external program: C:\Program Files\NUnit 2.4.8\bin\nunit-console.exe
Command line arguments: /assembly: <full-path-to-solution>\TestDSP\bin\Debug\TestDSP.dll

I'm using the console version there, but have tried the calling the GUI as well. Both give me the same error when I try and start debugging:

Cannot start test project 'TestDSP' because the project does not contain any tests.

Is this because I normally load \DSP.nunit into the Nunit GUI and that's where the tests are held?

I'm beginning to think the problem may be that VS wants to run it's own test framework and that's why it's failing to find the NUnit tests?

Edit: To those asking about test fixtures, one of my .cs files in the TestDSP project looks roughly like this:

namespace Some.TestNamespace
{
    // Testing framework includes
    using NUnit.Framework;

    [TestFixture]
    public class FirFilterTest
    {
        [Test]
        public void Test01_ConstructorTest()
        {
            ...some tests...
        }
    }
}

...I'm pretty new to C# and the NUnit test framework so it's entirely possible I've missed some crucial bit of information ;-)

Final Solution: The big problem was the project I'd used. If you pick Other Languages -> Visual C# -> Test -> Test Project ...when you're choosing the project type, Visual Studio will try and use it's own testing framework as far as I can tell. You should pick a normal C# class library project instead and then the instructions in my selected answer will work.

Answer 1

Install TestDriven.NET, which is a plugin for Visual Studio

From there you can right click on your unit test assembly and click Run Tests to run the whole suite, right click on a TestFixture class to run just the tests in that class, or right click on a Test method to run just that method.

You also have the option to Test With Debugger, if you need to breakpoint into your tests in debug mode.

Answer 2

When I need to debug my NUnit tests, I simply attach to the NUnit GUI application using "Debug|Attach to Process" and run the tests from the GUI. Any breakpoints in my tests (or the code they're testing) are hit. Am I misunderstanding your question, or will that work for you?

Answer 3

I use the same technique as you are trying Jon, without the /assembly flag, i.e.

Start External Program: C:\Program Files\NUnit 2.4.8\bin\nunit.exe

Command line arguments: "<path>\bin\Debug\Quotes.Domain.Tests.dll"

Does TestDSP.dll contain all your TestFixtures?

As my test project is not the startup project in the solution, I run my tests by right-clicking on the test project and choosing Debug --> Start New Instance

Answer 4

Try NUnitit - a open source Visual Studio Addin for Debugging NUnit Test cases

HomePage - http://nunitit.codeplex.com/

Answer 5

See if this helps.. http://stackoverflow.com/questions/196740/how-to-add-nunit-in-visual-studio

(RighteousRant)Although personally I don't like this approach.. If you need a debugger while you are test-driving your code, it's a "smell" in that you do not have enough confidence/know how your code works & need the debugger to tell you that. TDD should free you from needing a debugger if done right. Use 'Attach debugger to NUNit' only for rare cases or when you are wading in someone else's code.

Answer 6

It sounds like you are trying to use the wrong library. NUnit can only start if the dll you are using contains TestFixtures.

+1 on TestDriven.Net. I've had the chance to use it a number of times. You can download the personal version for evaluations purposes according the the license at http://testdriven.net/purchase_licenses.aspx.

Answer 7

Remove ProjectTypeGuids from the project file.

Answer 8

Regarding what Mr. Patrick McDonald said

As my test project is not the startup project in the solution, I run my tests by right-clicking on the test project and choosing Debug --> Start New Instance

I tried to apply for my test class library but got some error regarding the path, so I tried to remove the 'Command Line Arguments', and luckily it worked well and as expected.

Answer 9

I got the same error with MSTest. I found that in the Test Output window, some of the tests had duplicate IDs and could not be loaded. I removed all duplicate tests and now I was able to run the tests when i start the project.

Answer 10

Just like Steve said (sorry I can't simply upvote or comment, not enough reputation - i hate it), simply remove the line that looks like

<ProjectTypeGuids>
    {3AC096D0-A1C2-E12C-1390-A8335801FDAB};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}
</ProjectTypeGuids>

from your project file. This line basically tells VS.Net that it's a Test project, thus the "Cannot start test project". FYI here the 1st Guid says "it's a test", the 2nd says "it's C#". For information on those Guids: http://www.mztools.com/Articles/2008/MZ2008017.aspx