Unit testing business logic in maui project

[fgma]

I'm just getting started with maui and try to test my business logic. When adding a test project into my VS solution I can't reference the maui project for testing. I've also tried moving my business logic to a separate class library and test it there which also doesn't work. I'm always getting errors about unsupported target frameworks "net6.0-windows10.0.19041".

I don't care which framework to use at the moment. Just trying to get some tests running. I'm using latest VS2022 preview and started from the default code for a new project adding just a single class to it.

What is the way to go for unit testing with maui?

[jamesmontemagno]

One option is to break your logic you want to test out into another class library that targets just net6.0 and then you add that as a reference to your .NET MAUI app and your Unit Test project

[southsideringo]

This would be an excellent subject for a future video on your YouTube channel.

[kkohler2]

This won't really work. I have Converters that I have Xamarin.Forms tests for that work fine, but can't get working in Maui.

So something like:

    [Test]
    public void Convert()
    {
        // Arrange
        string rgbColor = "#ff0000";

        // Act
        var result = _rgbToColorConverter.Convert(rgbColor, null, null, null);

        // Assert
        Assert.AreEqual(Colors.Red, result);
    }

Except that Colors.Red requires use of Microsoft.Maui.Graphics, thus the unit test project needs to be a Maui project, but targeting net6.0.

I've tried updating my actual project by:
Adding target of net6.0
And updating the project file with the following, so it will compile as a library and an application:
<PropertyGroup Condition="'$(TargetFramework)' == 'net6.0'">
<OutputType>Library</OutputType>
</PropertyGroup>

So the scenario is:

1. Maui project w/ net6.0 target added and property group for net6.0 to compile as a library.
2. Maui unit test project (maui class library project w/ Microsoft.NET.Test.Sdk, NUnit, and NUnit3TestAdapter nuget packages, plus the unit tests) This project references the Maui project that creates the app.

Build the test project and try to run unit tests. I get errors for the results:

Severity Code Description Project File Line Suppression State
Error Empty ResolveFrameworkReference.RuntimePackPath while trying to read runtime components manifest. ResolvedFrameworkReference available: { Microsoft.NETCore.App, RuntimePackPath: } MauiTestProject C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.MonoTargets.Sdk\6.0.9\Sdk\RuntimeComponentManifest.targets 3

Severity Code Description Project File Line Suppression State
Error Empty ResolveFrameworkReference.RuntimePackPath while trying to read runtime components manifest. ResolvedFrameworkReference available: { Microsoft.NETCore.App, RuntimePackPath: } MauiTestProject C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.MonoTargets.Sdk\6.0.9\Sdk\RuntimeComponentManifest.targets 3

Anyone know how to fix these errors?

[fgma]

@jamesmontemagno I needed to create a new Maui library project and manually added an additional net6.0 target by editing the project. A normal .net core class library doesn't work because I can't reference it in the maui project anymore.

[Fabbrik1976]

I added <UseMaui>true</UseMaui> to my xunit project and then I was able to add the project to my MAUI solution.

[Craige]

I'm also having a similar problem with unit testing a Maui project with XUnit. I've created the test project, added net6.0 as a target framework to my main project, added <UseMaui> to the test project, and added a reference to the Maui project to the test project, but upon running dotnet test I get the following:

CSC : error CS5001: Program does not contain a static 'Main' method suitable for an entry point [.../path/to/MyMauiProject.csproj]

Creating a Main entry point in my Maui project does indeed allow the tests to execute, but breaks the Maui project build because the compiler gives the Main entry point priority over the MauiProgram.CreateMauiApp entry point.

Right now I can test by leaving the entry Main entry point in my code base and commenting or un-commenting it for testing/build, but that's obviously not a solution. What am I missing here?

[NeilMalcolm]

Try adding the following PropertyGroup to your csproj:

    <PropertyGroup Condition="'$(TargetFramework)' == 'net6.0'">
        <OutputType>Library</OutputType>
    </PropertyGroup>

[Craige]

Try adding the following PropertyGroup to your csproj [...]

That seems to be the element that I was missing. I need to output as a library when unit testing.

Thank you very much!

[TrueGeek]

I've got this working with the same trick that Fabbrik1976 showed. However, when I run

dotnet test --collect: "XPlat Code Coverage"

it shows 0 lines / branches in coverage.cobertura.xml. Anyone else having this problem?

[RichardMarsh]

I've got this working with the same trick that Fabbrik1976 showed. However, when I run

dotnet test --collect: "XPlat Code Coverage"

it shows 0 lines / branches in coverage.cobertura.xml. Anyone else having this problem?

Yup, same issue here.

[MahadevBansode]

Did anyone is able to fix these code coverage issue ? I am also facing same issue