chore: import upstream snapshot with attribution

Tests/ContainerizationExtrasTests/TestTimeout.swift

@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+// Copyright © 2025-2026 Apple Inc. and the Containerization project authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//===----------------------------------------------------------------------===//
+
+import Foundation
+import Testing
+
+@testable import ContainerizationExtras
+
+final class TestTimeoutType {
+    @Test
+    func testNoCancellation() async throws {
+        await #expect(throws: Never.self) {
+            try await Timeout.run(
+                for: .seconds(5),
+                operation: {
+                    return
+                })
+        }
+    }
+
+    @Test
+    func testCancellationError() async throws {
+        await #expect(throws: CancellationError.self) {
+            try await Timeout.run(
+                for: .milliseconds(50),
+                operation: {
+                    try await Task.sleep(for: .seconds(2))
+                })
+        }
+    }
+
+    @Test
+    func testClosureError() async throws {
+        // Check that we get the closures error if we don't timeout, but
+        // the closure does throw before.
+        await #expect(throws: POSIXError.self) {
+            try await Timeout.run(
+                for: .seconds(10),
+                operation: {
+                    throw POSIXError(.E2BIG)
+                })
+        }
+    }
+}