Implemented the "copyItem(from: to: )" function for the FileService service in the library target.

Tests/Library/Helpers/Mocks/FileServiceMock.swift

@@ -51,6 +51,19 @@ extension FileServiceMock: FileServicing {
     
     // MARK: Functions
     
+    func copyItem(from source: URL, to destination: URL) async throws (FileServiceError) {
+        guard let nextAction else { return }
+        
+        switch nextAction {
+        case .error(let error):
+            throw error
+        case let .copyItem(source, destination):
+            try await spy?.copyItem(from: source, to: destination)
+        default:
+            break
+        }
+    }
+    
     func createFolder(at location: URL) async throws (FileServiceError) {
         guard let nextAction else { return }
         
@@ -113,6 +126,7 @@ private extension FileServiceMock {
 
 extension FileServiceMock {
     enum Action {
+        case copyItem(URL, URL)
         case createFolder(URL)
         case deleteItem(URL)
         case error(FileServiceError)