Bundled the static files into the App test target.

Services/Website/Package.swift

@@ -120,7 +120,12 @@ let package = Package(
                     package: "hummingbird"
                 ),
             ],
-            path: "Tests/App"
+            path: "Tests/App",
+            resources: [
+                // `Static` links to the service's `Resources/Static`, copying it into the test bundle at build
+                // time — the tests must not read the repository tree, which Xcode's test runner is denied.
+                .copy("Static")
+            ]
         ),
         .testTarget(
             name: "WebsiteLibraryTests",

Services/Website/Tests/App/AppTests.swift

@@ -20,14 +20,18 @@ struct AppTests {
         .js
     ]
 
-    // Absolute path to the package's "Resources/Static" folder, derived from this
-    // file's location so the static files resolve regardless of the working directory.
-    private let staticFilesPath = URL(fileURLWithPath: #filePath)
-        .deletingLastPathComponent()  // Tests/App
-        .deletingLastPathComponent()  // Tests
-        .deletingLastPathComponent()  // package root
-        .appendingPathComponent(.Path.staticResources)
-        .path
+    // Absolute path to the copy of the package's "Resources/Static" folder made into the test bundle
+    // at build time — the repository tree itself is off limits to Xcode's test runner.
+    private let staticFilesPath: String = {
+        guard let url = Bundle.module.url(
+            forResource: "Static",
+            withExtension: nil
+        ) else {
+            preconditionFailure("The static files are missing from the test bundle.")
+        }
+
+        return url.path
+    }()
 
     // MARK: Functional tests
 

Services/Website/Tests/App/Static

@@ -0,0 +1 @@
+../../Resources/Static