Sources/Library/Protocols/FileServicing.swift

@@ -8,6 +8,7 @@ public protocol FileServicing {
     
     // MARK: Functions
     
+    func copyItem(from source: URL, to destination: URL) async throws (FileServiceError)
     func createFolder(at location: URL) async throws (FileServiceError)
     func deleteItem(at location: URL) async throws (FileServiceError)
     func isItemExists(at location: URL) async throws (FileServiceError) -> Bool
@@ -18,6 +19,7 @@ public protocol FileServicing {
 
 public enum FileServiceError: Error, Equatable {
     case folderNotCreated
+    case itemNotCopied
     case itemAlreadyExists
     case itemNotDeleted
     case itemNotExists

Sources/Library/Services/FileService.swift

@@ -21,6 +21,21 @@ public struct FileService: FileServicing {
     }
     
     // MARK: Functions
+    
+    public func copyItem(from source: URL, to destination: URL) async throws (FileServiceError) {
+        guard try await isItemExists(at: source) else {
+            throw FileServiceError.itemNotExists
+        }
+        guard try await !isItemExists(at: destination) else {
+            throw FileServiceError.itemAlreadyExists
+        }
+        
+        do {
+            try fileManager.copyItem(at: source, to: destination)
+        } catch {
+            throw FileServiceError.itemNotCopied
+        }
+    }
 
     public func createFolder(at location: URL) async throws (FileServiceError) {
         guard try await !isItemExists(at: location) else {

Tests/Library/Cases/Services/FileServiceTests.swift

@@ -26,6 +26,45 @@ struct FileServiceTests {
     
     // MARK: Functions tests
     
+    @Test(arguments: zip([URL.someExistingFile, .someExistingFolder],
+                         [URL.someNewFile, .someNewFolder]))
+    func copyItem(from source: URL, to destination: URL) async throws {
+        // GIVEN
+        let service = FileServiceMock(
+            currentFolder: .someCurrentFolder,
+            action: .copyItem(source, destination),
+            spy: spy
+        )
+
+        // WHEN
+        try await service.copyItem(from: source, to: destination)
+
+        // THENn
+        #expect(spy.actions.count == 1)
+        
+        let action = try #require(spy.actions.last)
+
+        #expect(action == .itemCopied(source, destination))
+    }
+    
+    @Test(arguments: [FileServiceError.itemNotExists, .itemAlreadyExists, .itemNotCopied])
+    func copyItem(throws error: FileServiceError) async throws {
+        // GIVEN
+        let service = FileServiceMock(
+            currentFolder: .someCurrentFolder,
+            action: .error(error),
+            spy: spy
+        )
+
+        // WHEN
+        // THEN
+        await #expect(throws: error) {
+            try await service.copyItem(from: .someExistingFile, to: .someNewFile)
+        }
+        
+        #expect(spy.actions.isEmpty == true)
+    }
+    
     @Test(arguments: [URL.someNewFolder, .someNewFile])
     func createFolder(with location: URL) async throws {
         // GIVEN

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)

Tests/Library/Helpers/Spies/FileServiceSpy.swift

@@ -18,6 +18,8 @@ extension FileServiceSpy: FileServicing {
         get async { .someCurrentFolder }
     }
     
+    func copyItem(from source: URL, to destination: URL) async throws (FileServiceError) {
+        actions.append(.itemCopied(source, destination))
     }
     
     func createFolder(at location: URL) async throws (FileServiceError) {
@@ -42,6 +44,7 @@ extension FileServiceSpy: FileServicing {
 extension FileServiceSpy {
     enum Action: Equatable {
         case folderCreated(_ location: URL)
+        case itemCopied(_ source: URL, _ destination: URL)
         case itemDeleted(_ location: URL)
         case itemExists(_ location: URL)
     }