chore: import upstream snapshot with attribution

dotnet/test/VectorData/SqliteVec.ConformanceTests/Support/SqliteVecRequiredAttribute.cs

@@ -0,0 +1,19 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using VectorData.ConformanceTests.Xunit;
+
+namespace SqliteVec.ConformanceTests.Support;
+
+/// <summary>
+/// Checks whether the sqlite_vec extension is properly installed, and skips the test(s) otherwise.
+/// </summary>
+[AttributeUsage(AttributeTargets.Method | AttributeTargets.Class | AttributeTargets.Assembly)]
+public sealed class SqliteVecRequiredAttribute : Attribute, ITestCondition
+{
+    public ValueTask<bool> IsMetAsync() => new(SqliteTestEnvironment.CanUseSqlite);
+
+    public string Skip { get; set; } = "Some native Sqlite dependencies are missing.";
+
+    public string SkipReason
+        => this.Skip;
+}