F# unit test projects in linux with mono (FAKE, NUnit 3)

Question

I am trying to set up a very simple test F# project in linux with mono, using Forge to set up the project and install nuget packages. Forge creates a build.fsx file which uses FAKE. I've tried to adjust this build file (in order to add tests) with inspiration from this tutorial http://fsharp.github.io/FAKE/gettingstarted.html. The tutorial, however, is using C# for testing and assumes Windows with .Net as environment. I want to use F# for testing and linux with mono as environment.

I think I almost got it working, but I am getting some cryptic error messages from NUnit. When running the build.fsx file I get following errors at the end:

...
Invalid argument: -nologo
The value '/home/michel/Documents/FSHARP/UnitTests/test/NUnit.Test.MyTests.dll' is not valid for option '--labels'.
Invalid argument: -xml:./test/TestResults.xml
Running build failed.
Error:
NUnit test failed (255).

---------------------------------------------------------------------
Build Time Report
---------------------------------------------------------------------
Target      Duration
------      --------
Clean       00:00:00.0036366
Build       00:00:00.0402828
BuildTest   00:00:00.4911710
Total:      00:00:00.7494956
Status:     Failure
---------------------------------------------------------------------
  1) Fake.UnitTestCommon+FailedTestsException: NUnit test failed (255).
  at Fake.NUnitSequential.NUnit (Microsoft.FSharp.Core.FSharpFunc`2 setParams, IEnumerable`1 assemblies) <0x41d27e50 + 0x0039f> in <filename unknown>:0 
  at [email protected] (Microsoft.FSharp.Core.Unit _arg4) <0x41d27dc0 + 0x0006f> in <filename unknown>:0 
  at Fake.TargetHelper+targetFromTemplate@195[a].Invoke (Microsoft.FSharp.Core.Unit unitVar0) <0x41cd59b0 + 0x00023> in <filename unknown>:0 
  at Fake.TargetHelper.runSingleTarget (Fake.TargetTemplate`1 target) <0x41ccb490 + 0x000ca> in <filename unknown>:0

My build.fsx file looks like this

// include Fake libs
#r "./packages/FAKE/tools/FakeLib.dll"

open Fake


// Directories
let buildDir  = "./build/"
let testDir = "./test/"

// version info
let version = "0.1"  // or retrieve from CI server

// Targets
Target "Clean" (fun _ ->
    CleanDirs [buildDir; testDir]
)

Target "Build" (fun _ ->
    //MSBuildDebug buildDir "Build" appReferences
    !! "/UnitTesting/*.fsproj"
    |> MSBuildRelease buildDir "Build"
    |> Log "AppBuild-Output: "
)

Target "BuildTest" (fun _ ->
                    !! "src/NUnit.Test.MyTests/*.fsproj"
                    |> MSBuildDebug testDir "Build"
                    |> Log "TestBuild-Output: "
)

Target "Test" (fun _ ->
               !! (testDir + "/NUnit.Test.MyTests.dll")
               |> NUnit (fun p ->
                         { p with
                               ToolPath = "packages/NUnit.ConsoleRunner/tools"
                               //DisableShadowCopy = true;
                               OutputFile = testDir + "TestResults.xml" })
)

Target "Default" (fun _ -> trace "HEEEELLOOOOOO world from FAKE!!!")

"Clean" ==> "Build" ==> "BuildTest" ==> "Test" ==> "Default"

RunTargetOrDefault "Default"

FAKE seems to be looking for a file nunit-console.exe under the packages/NUnit.ConsoleRunner/tools directory, but there is no such file. However, there is a nunit3-console.exe file, so I just made a copy of this file with the name nunit-console.exe.

My simple test file NUnit.Test.MyTests.fs looks like following:

namespace NUnit.Test.MyTests

module testmodule =

    open NUnit.Framework

    let SayHello name = "Hello"

    [<TestFixture>]
    type myFixture() =

        [<Test>]
        member self.myTest() =
            Assert.AreEqual("Hello World!", SayHello "World")

and the file test/NUnit.Test.MyTests.dll seems to be generated just fine.

What does the cryptic error message mean, and how can I fix it so I can run my tests?

Answer 1

As mentioned by rmunn in the comment, I need to use the function NUnit3 because I am using NUnit version 3.4.1. The function resides in the FAKE.Testing module http://fsharp.github.io/FAKE/apidocs/fake-testing-nunit3.html. I modified my build.fsx file so it now looks like following:

// include Fake libs
#r "./packages/FAKE/tools/FakeLib.dll"

open Fake
open Fake.Testing // NUnit3 is in here


// Directories
let buildDir  = "./build/"
let testDir = "./test/"

// version info
let version = "0.1"  // or retrieve from CI server
// Targets
Target "Clean" (fun _ ->
    CleanDirs [buildDir; testDir]
)

Target "Build" (fun _ ->
    !! "/UnitTesting/*.fsproj"
    |> MSBuildRelease buildDir "Build"
    |> Log "AppBuild-Output: "
)

Target "BuildTest" (fun _ ->
                    !! "src/NUnit.Test.MyTests/*.fsproj"
                    |> MSBuildDebug testDir "Build"
                    |> Log "TestBuild-Output: "
)

Target "Test" (fun _ ->
               !! (testDir + "/NUnit.Test.*.dll")
               |> NUnit3 (fun p ->
                         { p with
                               ToolPath = "packages/NUnit.ConsoleRunner/tools/nunit3-console.exe" })
)


Target "Default" (fun _ -> trace "HEEEELLOOOOOO world from FAKE!!!")

"Clean" ==> "Build" ==> "BuildTest" ==> "Test" ==> "Default"

RunTargetOrDefault "Default"

Note that you must specify ToolPath all the way to the nunit3-console.exe file, and not just the directory where it resides.

Now everything seems to work, and I get a fine and simple 'test-summary' in the console output when I run build.fsx. :)