Xamarin Unit Testing from the Command Line - unit-testing

Question

I'm coming from a native iOS / Android development background and I'm trying to understand the tooling around Xamarin Unit Testing using the Command Line.
From my point of view there are two types of code that you want to Unit Test:
Plain Old C# Code - with no dependencies to any iOS / Android framework - so it shouldn't need an iOS / Android emulator to run on
Code that depends on iOS / Android frameworks that needs to run on a device / emulator
The official Xamarin documentation mentions NUnitLite / Touch.Unit but it doesn't mention any support around Command Line. I did found an example though, but it's not clear to me if this is a tool that's officially supported by Xamarin. Also it seems that you can run tests only on the emulator/device using that tool.
Another example I've found around refers to xUnit.net - it seems that you can also run tests without an emulator / device, and that you can also run them on an emulator / device - however in that specific blogpost it's not documented how you do that.
So my question is: How should I approach Xamarin Unit Testing and what tools do you recommend using so I can have Command Line support in my CI.
Thank you

Answer 1

The most popular unit testing frameworks used with Xamarin are NUnit and XUnit. They are both similar to JUnit.
Usually a Xamarin cross-platform app uses a Portable Class Library (PCL) project where the platform agnostic (shared) code sits: business logic, model, view models, service etc. This code is unit tested in a seperate pcl or.net45 test project which references the source project and nunit/xunit.
To run the nunit/xunit unit tests you need to run the corresponding test runner and point it tou your test assembly. Both nunit and xundit feature console runners which can be parameterized at will from your command line (see links).
Feel free to chose either nunit or xunit. I like them both.
You might also have platform specific unit tests (which depend on the android/ios/uwp sdks) and that have to be run on a device. These tests can also be created with nunit or xunit and run with nunit device runner or xunit device runner. Basically what will happen here is you add an android/ios app project for testing which references nunit/junit, contains your device specific tests and links to your shared tests and can run them both on the device.
There is also the layer of coded UI tests where NUnit, Xamarin UITest and Specflow might be of use. Im guessing this part is beyond the scope of your question.
But then again you are coming form Android and are used with gradle. Well Xamarin and .net does not have gradle but it has Cake. I use it to automate all my project builds/tests/ci/deployments etc.
Cake (C# Make) is a cross platform build automation system with a C# DSL to do things like compiling code, copy files/folders, running unit tests, compress files and build NuGet packages.
Your Cake script can look something like this:
Task("Run-Unit-Tests")
.IsDependentOn("Build")
.Does(() =>
{
NUnit("./src/**/bin/" + configuration + "/*.Tests.dll");
});
Task("Build")
.Does(() =>
{
DotNetBuild("YourAndroid.csproj");
DotNetBuild("YourCoreTests.csproj");
...
}
);
Cake comes with a bootstrapper file either (ps1 - powershell for windows or sh for mac) which downloads all the tools you need to run your script (cake itself, nuget, nunit/xunit runner etc).
Your command line/CI can run it like this:
./build.sh -Target Run-Unit-Tests

Answer 2

Unit testing in painful on Xamarin.
Don't have huge experience in Unit Testing mobile project, but if you want to test the app I would recommend this integration test approach:
1) For any calculation type functionality (you called it "Plain Old C#") use NUnit (it is supported by mono).
However I cannot come up with an example of such code, as heavy calculations should be done on server side. And there you do separate Unit tests
2) UITests(NUnit again) can be done to prove app is working and UI interaction call needed behavior.
Xamarin also providing TestCloud where app could be tested on many devices, but it is paid for Service. As Alternative you can setup build server like Jenkins to do this job for you.
Anyway - it is my view on how this could be done and hope it answered a bit on your question.