You are testing your apps, right?
Because testing is important. So in this video, we're going to learn how to use
xUnit together with your .NET MAUI application. I have seen a couple of people who
have been wondering like, how do I test my, well, unit test
application? So they added this xUnit test
project to their solution for .NET MAUI. But then they
run into trouble with all kinds of weird error messages that things
cannot be run or the test doesn't run or it doesn't even build
at all. So, to show you how to actually do this, I created
this little video to show you how to add a xUnit project to your .NET
MAUI solution so that you can test code that is
actually in your .NET MAUI application. So let's just switch over
to Visual Studio and show you how it's done. Here we are in Visual Studio
2022. I've created a file new .NET MAUI application. You can see
it here running on Windows. But in this case, the application
itself is not really that important because I'm not going to show you how to
actually do the tests, implement all your business logic and
actually test that. I'm just going to show you how to add the unit test project
in here and then it's up to you to write the actual tests.
So let's close down this and here in our solution, we just have
this single project, which is our .NET MAUI application. And then people
would start adding their unit test project and actually
start testing code in their .NET MAUI application. That seems like a
good approach, right? So let's do that. Let's go to our
solution. Click Add, New Project and here we can search for
xUnit. So there is different unit test frameworks out
there. xUnit is fairly popular right now and you can run this
on Windows, Linux and macOS. So that seems like a logical
choice if you want to have this cross platform application, right? So let's
do that. Let's click next, I'm going to name this UnitTestProject. Doesn't
really matter what the name is, it probably makes more
sense for you if you call it something different. The framework
that should probably match whatever is in your .NET MAUI project. For now
the only option is .NET 6, but in the future it will be .NET
7, 6, et cetera, et cetera. So choose the right one. So we're
going to create that. It will think a little bit and it will create our
project with a little scaffolding code here. Unit test one, fact test
one, et cetera, et cetera. Now, this unit test project
should build. It should just run. In fact, this test
should succeed because it doesn't do anything. So
whenever I right click here and I do run tests, it will bring up the
Test Explorer. I think it's going to build these
little application because this is just how unit testing works.
It's a DLL and it gets picked up by the framework with
these attributes and it will start running through all these tests. You can
already see the little thing here. Test has passed. Show Test Explorer. Here
we are. And this test has passed. So that's great. But what
we didn't do is add a dependency, add a reference to our .NET MAUI application. So go here
to dependencies in your unit test project. We're going to right click
add project reference. And here we have our MauixUnitTestSample, which is
the name of our .NET MAUI application. So let's check that box.
And now it made a reference to the .NET MAUI application. And now
we can actually reference code from our
.NET MAUI application because there's probably services in there or your
business logic and whatnot that you actually want to test from there, right? So now
you can create all references from all the objects in that project
and you can actually start testing. But whenever you want to do the same
thing now and you say, hey, here, I want to run all the tests,
then it's going to build again. And you can immediately see like, hey,
whoa, this doesn't work, it's not compatible. This is not even going to
build. So how to fix this? Well, what's
causing this actually is because .NET MAUI, well, we don't
even need to right click. We just click
once on the csproj here. Or you can right click and do Edit... I think you
have to unload it. Oh no, here it is. Edit Project File.
You will get this view and you can see these target
frameworks, which is Android iOS Mac Catalyst, maybe
Windows if you're on here. But if we'll do the
same thing in our unit test project here, you can see that
the target framework is net6.0 so the targets don't align.
And that's something that needs to be fixed. So let's also add a
net6.0 target to our .NET MAUI application. We can do
that very easily by just adding net-6.0 here
and a little semicolon. And now we've
added the net6 target. But the problem is that we also need
to output this as a DLL, as a library. But here
the output type says exe, right? That is needed for
all the other targets in here, Android,
iOS, Mac Catalyst. To be very honest, I don't really know why that is.
Probably for historical reasons, but it needs to be there. And
we can kind of easily fix this as well. If you know a little bit
about the build engine, I think we can scroll down here and we can
actually take some inspiration from down here a little bit up. We
have this condition right here. And now what we want to do
is only do this output type to an EXE whenever the
condition is not net-6.0 because the default value for
this is Library and otherwise we're going to do this
in Android. Actually, let me just copy this from
here. I have this prepared. So for this OutputType, on every node
you can do this condition. And whenever the TargetFramework,
that's a variable is not net-6.0, so it's not this one, then we're going to do this EXE. So for
all the target frameworks in here, as long as it's not that one,
it's going to be EXE. And the default value of output type
is Library. So whenever we have this net-6.0, this is not going
to be included. It's going to fall back to the default value of
Library and we're good to go. Actually, I think this is all we need
to do to actually make this build again. I think this might still
cause an error because you have to kind of like
unload and reload your projects. At least that's what I ran into earlier. It
still didn't really build until, I don't know, fiddled a little bit. So
maybe to be very sure, just close your Visual Studio after
you do this, open it up again and then everything will reload properly.
Although this seems to go quite smoothly, so it
seems to maybe be good. But this should allow you to
automatically start building your unit tests
actually, write your unit test. You can write them now and it should
build and actually complete. But what you also might want to do at some point is
actually access .NET MAUI APIs from your unit test. So maybe you want
to access, I don't know, some APIs, some controls
that are in .NET MAUI that need to be unit tested.
I don't know, you don't want to unit test our stuff, we already do that.
But there might be some API that you need to check things against. So if
that's the case, go back to your xUnit test
project and what you can then do is basically say, <UseMaui> and set this to true and now it will pull in the .NET MAUI library and it
will allow you to actually also access all the .NET MAUI APIs. You can use those in
your unit test project as well, if that's what you need. Like
I said, this doesn't really build. I don't know what I did last time to
actually make it work, but you probably want to unload and do
all the things. Let me try to run this thing
here again while I talk you through the rest. But if you unload and reload
or maybe restart your visual studio, then it
really works. Pinky promise. See, here we are. I think the build
actually succeeded right now. So it's actually running the test and the test
succeeds. See? So now after a little bit of fiddling here, it
actually works. And this is how you can add a unit test project to your .NET
MAUI application. Now this allows you to add C unit testing project to
your net Maui solution. Another way around if you actually
want to use those cross platform APIs or you actually want to
run it on a device, because in some scenarios there is
definitely a difference in behavior, whenever you run it on an
actual device, you also have device runners. And to run that on Android and iOS and
run your unit tests actually on the device, that is not
what this does. This is purely for basically your .NET only code to
allow you to unit test that right from your
.NET MAUI application. So I hope this was meaningful to you.
The source code attached to this, just so you know how
to actually repeat this, it's in the GitHub repository that is
down in the video description below. I've added little comments that are
marked with xUnit inside of the csproj. So you can easily know
what you actually have to do. If you like this video, please click
the like button, which will spread to more people. And all those people can
actually start testing because testing is important people. And of course if you
want to know more about .NET MAUI, be sure to check out this playlist
right here. There is a recommended video right here. Please click this button
so you're subscribed to my channel and I'll be seeing you for the next one.
