Extensibility- Plugins

Learn how to plugin your logic in BELLATRIX test workflow using plugins.

Introduction

The test workflow plugins are way to execute your logic before each test. For example- taking screenshots or videos on test failures, creating custom logs and so on. In the example you can find a plugin that integrates a ManualTestCase attribute for the automated tests, containing the ID to the corresponding manual test case. The main purpose of the test workflow is to fail the test if the ManualTestCase attribute is not set.

Example

[AttributeUsage(AttributeTargets.Method)]
public class ManualTestCaseAttribute : Attribute
{
    public ManualTestCaseAttribute(int testCaseId) => TestCaseId = testCaseId;

    public int TestCaseId { get; set; }
}

public class AssociatedPlugin : Plugin
{
    protected override void PreTestInit(object sender, PluginEventArgs e)
    {
        base.PreTestInit(sender, e);
        ValidateManualTestCaseAttribute(e.TestMethodMemberInfo);
    }

    private void ValidateManualTestCaseAttribute(MemberInfo memberInfo)
    {
        if (memberInfo == null)
        {
            throw new ArgumentNullException();
        }

        var methodBrowserAttributes = memberInfo.GetCustomAttributes<ManualTestCaseAttribute>(true).ToList();
        if (methodBrowserAttributes.Count == 0)
        {
            throw new ArgumentException("No manual test case is associated with the BELLATRIX test.");
        }
        else if (methodBrowserAttributes.Count > 1)
        {
            throw new ArgumentException("You cannot associate two manual test cases with a single BELLATRIX test.");
        }
        else if (methodBrowserAttributes.First().TestCaseId <= 0)
        {
            throw new ArgumentException("The associated manual test case ID cannot be <= 0.");
        }
    }
}

Explanations

public class AssociatedPlugin : Plugin

To create a custom test workflow plugin:

Create a new class that derives from the ‘Plugin’ base class.
Then override some of the workflow’s protected methods adding there your logic.
Register the workflow plugin using the AddPlugin method of the App service.

protected override void PreTestInit(object sender, PluginEventArgs e)
{
    base.PreTestInit(sender, e);
    ValidateManualTestCaseAttribute(e.TestMethodMemberInfo);
}

You can override all mentioned test workflow method hooks in your custom handlers. The method uses reflection to find out if the ManualTestCase attribute is set to the run test. If the attribute is not set or is set more than once an exception is thrown. The logic executes before the actual test run, during the PreTestInit phase.

[TestFixture]
[Android(Constants.AndroidNativeAppPath,
    Constants.AndroidDefaultAndroidVersion,
    Constants.AndroidDefaultDeviceName,
    Constants.AndroidNativeAppAppExamplePackage,
    ".view.Controls1",
    AppBehavior.ReuseIfStarted)]
public class CustomTestCaseExtensionTests : AndroidTest
{
    public override void TestInit()
    {
        App.AddPlugin<AssociatedTestCaseExtension>();
    }

    [Test]
    [ManualTestCase(1532)]
    public void ButtonClicked_When_CallClickMethod()
    {
        var button = App.Components.CreateByIdContaining<Button>("button");

        button.Click();
    }
}

Once we created the test workflow plugin, we need to add it to the existing test workflow. It is done using the App service’s method AddPlugin.

[OneTimeSetUp]
public void AssemblyInitialize()
{
    App.AddPlugin<AssociatedTestCaseExtension>();
}

It doesn’t need to be added multiple times as will happen here with the TestInit method. Usually this is done in the TestsInitialize file in the AssemblyInitialize method.

Screenshot and Video Generation Plug-ins

Your plug-ins can plug in the screenshots and video generation on fail. To do a post-screenshot generation action, implement the IScreenshotPlugin interface and add your logic to ScreenshotGenerated method. To do a post-video generation action, implement the IVideoPlugin interface and add your logic to VideoGenerated method. Bellow you can find a sample usage from BELLATRIX Allure plug-in.

public class AllureWorkflowPlugin : Plugin, IScreenshotPlugin, IVideoPlugin
{
    private static AllureLifecycle _allureLifecycle => AllureLifecycle.Instance;
    private string _testContainerId;
    private string _testResultId;
    private bool _hasStarted = false;

    public void SubscribeScreenshotPlugin(IScreenshotPluginProvider provider)
    {
        provider.ScreenshotGeneratedEvent += ScreenshotGenerated;
    }

    public void UnsubscribeScreenshotPlugin(IScreenshotPluginProvider provider)
    {
        provider.ScreenshotGeneratedEvent -= ScreenshotGenerated;
    }

    public void ScreenshotGenerated(object sender, ScreenshotPluginEventArgs e)
    {
        if (File.Exists(e.ScreenshotPath))
        {
            _allureLifecycle.AddAttachment("image on fail", "image/png", e.ScreenshotPath);
        }
    }

    public void SubscribeVideoPlugin(IVideoPluginProvider provider)
    {
        provider.VideoGeneratedEvent += VideoGenerated;
    }

    public void UnsubscribeVideoPlugin(IVideoPluginProvider provider)
    {
        provider.VideoGeneratedEvent -= VideoGenerated;
    }

    public void VideoGenerated(object sender, VideoPluginEventArgs e)
    {
        if (File.Exists(e.VideoPath))
        {
            _allureLifecycle.AddAttachment("video on fail", "video/mpg", e.VideoPath);
        }
    }

    // rest of the code...
}