'Failed to start remote test agent' when using nunit.engine.dll in custom runner

• Method of installation: NuGet
• Version of the NUnit Engine: 3.6.1

I’m writing a custom runner app (.NET Framework v4.6.2) and have added the nunit.engine and nunit.engine.api NuGe packages to the project. My project only references nunit.engine.api. I’m following this doc here: https://docs.nunit.org/articles/nunit/technical-notes/nunit-internals/Test-Engine-API.html

Here’s my Program.cs:

internal class Program
{
    public static void Main(string[] args)
    {
        // Get an interface to the engine
        ITestEngine engine = TestEngineActivator.CreateInstance();

        // Create a simple test package - one assembly, no special settings
        TestPackage package = new TestPackage("tests.dll");
        
        // Get a runner for the test package
        ITestRunner runner = engine.GetRunner(package);
        
        var testEventListener = new MyTestEventListener();

        // Run all the tests in the assembly
        XmlNode testResult = runner.Run(testEventListener, TestFilter.Empty);
    }
}

When I execute the program I get this:

Unhandled Exception: NUnit.Engine.NUnitEngineException: Failed to start remote test agent.
   at NUnit.Engine.Services.TestAgency.OnAgentExit(Process process, Guid agentId)
   at NUnit.Engine.Services.TestAgency.<>c__DisplayClass7_0.<LaunchAgentProcess>b__0(Object sender, EventArgs e)
   at System.Diagnostics.Process.OnExited()
   at System.Diagnostics.Process.RaiseOnExited()
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading._ThreadPoolWaitOrTimerCallback.PerformWaitOrTimerCallback(Object state, Boolean timedOut)

Then a second later I get:

Unhandled Exception: System.TypeLoadException: Could not load type 'NUnit.Engine.NUnitEngineUnloadException' from assembly 'nunit.engine.api, Version=3.0.0.0, Culture=neutral, PublicKeyToken=2638cd05610744eb'.
   at NUnit.Common.ExceptionHelper.FlattenExceptionHierarchy(Exception exception)
   at NUnit.Common.ExceptionHelper.BuildMessageAndStackTrace(Exception exception)
   at NUnit.Engine.Runners.ProcessRunner.RunTests(ITestEventListener listener, TestFilter filter)
   at NUnit.Engine.Runners.MasterTestRunner.RunTests(ITestEventListener listener, TestFilter filter)
   at NUnit.Engine.Runners.MasterTestRunner.Run(ITestEventListener listener, TestFilter filter)
   at Zzz.Program.Main(String[] args) in C:\Zzz\Program.cs:line xx

I tried running my tests.dll with nunit3-console and it seems to work fine so I don’t think the tests assembly is at fault.

[CharliePoole]

@kyle-v-51 The console output is pretty straightforward based on the XML result as well as various XML-formatted events that are fired while the test runs. Take a look at the code in the console project or in the NUnitLite assembly (different code that does basically the same thing)

[kyle-v-51]

Looks like updating the engine/API NuGet package to latest fixed the issue.

As an aside, I see my report comes back as XML – is there a way to get all the same output I see when running a test via the nunit console too?