chore: import upstream snapshot with attribution

dotnet/test/VectorData/VectorData.ConformanceTests/Xunit/ConditionalFactDiscoverer.cs

@@ -0,0 +1,23 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace VectorData.ConformanceTests.Xunit;
+
+/// <summary>
+///     Used dynamically from <see cref="ConditionalFactAttribute" />.
+///     Make sure to update that class if you move this type.
+/// </summary>
+public class ConditionalFactDiscoverer(IMessageSink messageSink) : FactDiscoverer(messageSink)
+{
+    protected override IXunitTestCase CreateTestCase(
+        ITestFrameworkDiscoveryOptions discoveryOptions,
+        ITestMethod testMethod,
+        IAttributeInfo factAttribute)
+        => new ConditionalFactTestCase(
+            this.DiagnosticMessageSink,
+            discoveryOptions.MethodDisplayOrDefault(),
+            discoveryOptions.MethodDisplayOptionsOrDefault(),
+            testMethod);
+}