ℹ️

Note: This guide covers steps for setting up an Android NUnit test project, not a Xamarin.UITest project. Xamarin.UITest guides can be found here.

When you create an Android Unit Test Project [Xamarin Studio] or Unit Test App (Android) [Visual Studio], by default it will not automatically run your tests. To automate your android Unit Test: To run NUnit tests on a target device, we use an Android.App.Instrumentation subclass, which can be created and executed by using the adb shell am instrument command.

First, we create the TestInstrumentation.cs file, which creates a subclass of Xamarin.Android.NUnitLite.TestSuiteInstrumentation (declared in Xamarin.Android.NUnitLite.dll). The TestInstrumentation(IntPtr, JniHandleOwnership) constructor must be provided, and the virtual AddTests() method must be overridden. AddTests() controls which tests are actually executed. This file is largely boilerplate.

Next, the .csproj must be modified to add TestInstrumentation.cs.

Optionally, the .csproj may be modified to add the RunTests MSBuild target, which would allow invoking the unit tests as:

msbuild /t:RunTests Project.csproj

Using a new target is not required; the corresponding adb command may be used instead:

adb shell am instrument -w @PACKAGE_NAME@/app.tests.TestInstrumentation

Replace @PACKAGE\_NAME@ as appropriate; it is the value present in the AndroidManifest.xml /manifest/@package attribute.

Important Note: With the Xamarin.Android 5.0 release, the default package names for Android Callable Wrappers will be based on the MD5SUM of the assembly-qualified name of the type being exported. This allows the same fully-qualified name to be provided from two different assemblies and not get a packaging error. So make sure that you use the `Name` property on the `Instrumentation` attibute to generate a readable ACW/class name.

The ACW name must be used in the adb command. Renaming/refactoring the C# class will thus require modifying the RunTests command to use the correct ACW name.

Additions to the .csproj file:

<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <ItemGroup>
        <Compile Include="TestInstrumentation.cs" />
    </ItemGroup>
    <Target Name="RunTests" DependsOnTargets="_ValidateAndroidPackageProperties">
        <Exec Command=""$(_AndroidPlatformToolsDirectory)adb" $(AdbTarget) $(AdbOptions) shell am instrument -w $(_AndroidPackage)/app.tests.TestInstrumentation" />
    </Target>
</Project>

TestInstruments.cs:

using System;
using System.Reflection;

using Android.App;
using Android.Content;
using Android.Runtime;

using Xamarin.Android.NUnitLite;

namespace App.Tests {

    [Instrumentation(Name="app.tests.TestInstrumentation")]
    public class TestInstrumentation : TestSuiteInstrumentation {

        public TestInstrumentation (IntPtr handle, JniHandleOwnership transfer) : base (handle, transfer)
        {
        }

        protected override void AddTests ()
        {
            AddTest (Assembly.GetExecutingAssembly ());
        }
    }
}