chore: import upstream snapshot with attribution

Tests/ContainerizationTests/HashTests.swift

@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+// 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 Containerization
+
+struct HashTests {
+
+    @Test func hashMountSourceWithValidString() throws {
+        let result = try hashFilePath(path: "/valid/path")
+
+        // Should produce a non-empty hash
+        #expect(!result.isEmpty)
+
+        // Same input should produce same hash (deterministic)
+        let result2 = try hashFilePath(path: "/valid/path")
+        #expect(result == result2)
+
+        // Different inputs should produce different hashes
+        let result3 = try hashFilePath(path: "/different/path")
+        #expect(result != result3)
+    }
+}