TestCaseExtensions.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using Xunit.Sdk;

#nullable enable
namespace Microsoft.DotNet.XHarness.TestRunners.Xunit;

/// <summary>
/// Useful extensions that make working with the ITestCaseDiscovered interface nicer within the runner.
/// </summary>
public static class TestCaseExtensions
{
    /// <summary>
    /// Returns boolean indicating whether the test case does have traits.
    /// </summary>
    /// <param name="testCase">The test case under test.</param>
    /// <returns>true if the test case has traits, false otherwise.</returns>
    public static bool HasTraits(this ITestCaseDiscovered testCase) =>
        testCase.Traits != null && testCase.Traits.Count > 0;

    public static bool TryGetTrait(this ITestCaseDiscovered testCase,
                                   string trait,
                                   [NotNullWhen(true)] out List<string>? values,
                                   StringComparison comparer = StringComparison.InvariantCultureIgnoreCase)
    {
        if (trait == null)
        {
            values = null;
            return false;
        }

        // there is no guarantee that the dict created by xunit is case insensitive, therefore, trygetvalue might
        // not return the value we are interested in. We have to loop, which is not ideal, but will be better
        // for our use case.
        foreach (var t in testCase.Traits.Keys)
        {
            if (trait.Equals(t, comparer))
            {
                values = testCase.Traits[t].ToList();
                return true;
            }
        }

        values = null;
        return false;
    }

    /// <summary>
    /// Get the name of the test class that owns the test case.
    /// </summary>
    /// <param name="testCase">TestCase whose class we want to retrieve.</param>
    /// <returns>The name of the class that owns the test.</returns>
    public static string? GetTestClass(this ITestCaseDiscovered testCase) =>
        testCase.TestClassName?.Trim();

    public static string? GetNamespace(this ITestCaseDiscovered testCase)
    {
        var testClassName = testCase.GetTestClass();
        if (testClassName == null)
        {
            return null;
        }

        int dot = testClassName.LastIndexOf('.');
        return dot <= 0 ? null : testClassName.Substring(0, dot);
    }
}