Deque.AxeCore.Playwright 4.10.0

Deque.AxeCore.Playwright

Automated web accessibility testing with .NET, C#, and Playwright. Wraps the axe-core accessibility scanning engine and the Playwright browser automation framework.

Compatible with .NET Standard 2.1.

Getting Started

Install via NuGet:

PM> Install-Package Deque.AxeCore.Playwright
# or, use the Visual Studio "Manage NuGet Packages" UI

Ensure you have Playwright browsers installed. For reference, see https://playwright.dev/dotnet/docs/browsers

Example usage with Playwright's NUnit integration:

using System.Threading.Tasks;
using NUnit.Framework;
using Microsoft.Playwright.NUnit;
using Deque.AxeCore.Commons;
using Deque.AxeCore.Playwright;

[TestFixture]
class MyPlaywrightTests : PageTest
{
    [Test]
    public async Task CheckAxeClean()
    {
        const string expectedViolationId = "color-contrast";

        await Page!.GotoAsync("https://playwright.dev/dotnet");

        AxeResult axeResults = await Page!.RunAxe();
        Assert.That(axeResults.Violations, Is.Null.Or.Empty);
    }
}

API Reference

This library essentially wraps the axe-core library. Currently the two supported functions are for rule retrieval and for running.

GetAxeRules

This method retrieves metadata about the rules that axe is capable of running.

IList<AxeRuleMetadata> axeRules = await page.GetAxeRules();
foreach(var rule in axeRules)
{
    Console.WriteLine($"Rule name: {rule.RuleId} Help: {rule.Help} HelpUrl: {rule.HelpUrl}");
    Console.WriteLine($"Tags: {string.Join(", ", rule.Tags)}");
}

It is also possible to run this only selecting for rules with particular tags. Tags are considered in a disjunctive fashion.

// Only take rules which are wcag2aa or wcag2a.
IList<string> tags = new List<string>() { "wcag2aa", "wcag2a"}

IList<AxeRuleMetadata> axeRules = await page.GetAxeRules(tags);
foreach(var rule in axeRules)
{
    Console.WriteLine($"Rule name: {rule.RuleId} Help: {rule.Help} HelpUrl: {rule.HelpUrl}");
    Console.WriteLine($"Tags: {string.Join(", ", rule.Tags)}");
}

RunAxe

This method executes the axe.run API, which will run rules against the current state of the page.

AxeResult axeResults = await page.RunAxe();

Console.WriteLine($"Axe ran against {axeResults.Url} on {axeResults.Timestamp}.");

Console.WriteLine($"Rules that failed:");
foreach(var violation in axeResults.Violations)
{
    Console.WriteLine($"Rule Id: {violation.Id} Impact: {violation.Impact} HelpUrl: {violation.HelpUrl}.");

    foreach(var node in violation.Nodes)
    {
        Console.WriteLine($"\tViolation found at: {node.Target}");
        Console.WriteLine($"\t...with HTML: {node.Html}");
    }
}

Console.WriteLine($"Rules that passed successfully:");
foreach(var pass in axeResults.Passes)
{
    Console.WriteLine($"Rule Id: {pass.Id} Impact: {pass.Impact} HelpUrl: {pass.HelpUrl}.");
}

Console.WriteLine($"Rules that did not fully run:");
foreach(var incomplete in axeResults.Incomplete)
{
    Console.WriteLine($"Rule Id: {incomplete.Id}.");
}

Console.WriteLine($"Rules that were not applicable:");
foreach(var inapplicable in axeResults.Inapplicable)
{
    Console.WriteLine($"Rule Id: {inapplicable.Id}.");
}

RunAxe is supported on both Playwright Pages and Playwright Locators. Locators are the easiest way to run axe against only part of a page:

ILocator locator = page.Locator("text=Sign In");

AxeResult axeResults = await locator.RunAxe();

Alternately, when used on a Page, RunAxe supports an AxeRunContext parameter which supports more complex rules for deciding which parts of a page to scan (or exclude from a scan). This corresponds to the axe.run Context parameter:

AxeRunContext runContext = new AxeRunContext()
{
    // Only run on this #my-id.
    Include = new List<AxeSelector>() { new AxeSelector("#my-id") }
};

runContext = new AxeRunContext()
{
    // Run on everything except #my-id and #second-id.
    Exclude = new List<AxeSelector>()
    {
        new AxeSelector("#my-id"),
        new AxeSelector("#second-id"),
    }
};

runContext = new AxeRunContext()
{
    // Run on every button except #my-id.
    Include = new List<AxeSelector>() { new AxeSelector("button") },
    Exclude = new List<AxeSelector>() { new AxeSelector("#my-id") }
};

runContext = new AxeRunContext()
{
    // Run on everything, except for #my-id within the iframe #my-frame.
    Exclude = new List<AxeSelector>()
    {
        new AxeSelector("#my-id", new List<string>() { "#my-frame" })
    }
};

AxeResult axeResults = await page.RunAxe(runContext);

All RunAxe methods also support an AxeRunOptions parameter. This corresponds to the axe.run Options parameter.

AxeRunOptions options = new AxeRunOptions()
{
    // Run only tags that are wcag2aa.
    RunOnly = new RunOnlyOptions { Type = "tag", Values = new List<string> { "wcag2aa" } },

    // Specify rules.
    Rules = new Dictionary<string, RuleOptions>()
    {
        // Don't run color-contrast.
        { "color-contrast", new RuleOptions() { Enabled = false } }
    },

    // Limit result types to Violations.
    ResultTypes = new HashSet<ResultType>()
    {
        ResultType.Violations
    },

    // Don't return css selectors in results.
    Selectors = false,

    // Return CSS selector for elements, with all the element's ancestors.
    Ancestry = true,

    // Don't return xpath selectors for elements.
    XPath = false,

    // Don't run axe on iframes inside the document.
    Iframes = false
};

AxeResult axeResults = await page.RunAxe(options);
axeResults = await page.RunAxe(context, options);
axeResults = await locator.RunAxe(options);

RunAxeLegacy

Set the frame testing method to "legacy mode". In this mode, axe will not open a blank page in which to aggregate its results. This can be used in an environment where opening a blank page causes issues.

With legacy mode turned on, axe will fall back to its test solution prior to the 4.3 release, but with cross-origin frame testing disabled. The frame-tested rule will report which frames were untested.

Important: Use of .RunAxeLegacy() is a last resort. If you find there is no other solution, please report this as an issue. It will be removed in a future release.

AxeResult axeResults = await page.RunAxeLegacy();

Migrating from Playwright.Axe (PlaywrightAxeDotnet)

This project acts as a drop-in replacement for most of the functionality from Playwright.Axe. (PlaywrightAxeDotnet). To migrate:

1. Update your test .csproj file's <PackageReference> for Playwright.Axe to Deque.AxeCore.Playwright
2. Add a new <PackageReference> to Deque.AxeCore.Commons at the same version number as Deque.AxeCore.Playwright
3. Update all using Playwright.Axe; statements in your tests to using Deque.AxeCore.Playwright; and/or using Deque.AxeCore.Commons;

In a move to standardize, we migrated this package away from Playwright specific typings, instead opting to use the typings from the Deque.AxeCore.Commons package instead. The result is several minor breaking changes that may require updates to your code:

Replacements/Renamings

1. AxeResults has now been renamed to AxeResult; the previously used AxeResult for this package will now be AxeResultItem.
2. AxeNodeResult has been replaced with AxeResultNode
3. AxeCheckResult has been replaced with AxeResultCheck
4. AxeResultGroup has been replaced with ResultType
5. AxeRuleObjectValue has been replaced with RuleOptions
6. AxeRunOnly has been replaced with RunOnlyOptions
7. AxeRelatedNode has been replaced with AxeResultRelatedNode. With this type, the Targets property is changed from a IList<string> to a List<AxeResultTarget>; users should expect to modify usages of the Targets property to include a .ToString() method call.
8. AxeRunSerialContext has been replaced by AxeRunContext and AxeSelector types. Here are some examples of how to use the new types:

// Finding a single element using the Playwright Locator API.
ILocator locator = page.GetByRole("menu").RunAxe();

// Including/excluding elements in the main frame.
new AxeRunContext()
{
    Include = new List<AxeSelector> { new AxeSelector("#foo") },
    Exclude = new List<AxeSelector> {},
};

// Including/excluding an element in a child frame.
new AxeRunContext()
{
    Include = new List<AxeSelector> { new AxeSelector("#element-in-child-frame", new List<string> { "#iframe-in-main-frame" })},
    Exclude = new List<AxeSelector> {},
};

Type Modifications

1. The Timestamp type in AxeResult changed from System.DateTime to System.DateTimeOffset
2. The url type in AxeResult changed from Uri to string
3. The OrientationAngle type in AxeTestEnvironment changed from int to double
4. The HelpUrl in AxeResultItem changed from Uri to string

Removals

1. Removed AxeEnvironmentData interface and using the existing environment data info in Deque.AxeCore.Commons.AxeResult
2. Removed AxeImpactValue and AxeRunOnlyType enums in favor of using string in the Commons typings (AxeResultItem.cs and AxeRunOptions.cs, respectively)
3. FailureSummary was removed from AxeResultNode (formerly AxeNodeResult)
4. ElementRef and PerformanceTimer were removed from AxeRunOptions
5. AxeRunOptions and RunOnlyOptions now use named object-initializer syntax instead of constructor parameters.

Contributing

Refer to the general axe-core-nuget CONTRIBUTING.md.

License

This package is distributed under the terms of the MIT License.

However, note that it has a dependency on the (MPL licensed) Deque.AxeCore.Commons NuGet package.

Acknowledgements

This package builds on past work from the PlaywrightAxeDotnet project (see NOTICE.txt). We @IsaacWalker for his work on that project.