Implemented the "createFile(at: with: )" function for the FileService service in the library target.

Library/Sources/Public/Protocols/FileServicing.swift

@@ -9,6 +9,7 @@ public protocol FileServicing {
     // MARK: Functions
     
     func copyFile(from source: URL, to destination: URL) async throws (FileServiceError)
+    func createFile(at location: URL, with data: Data) 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 +19,8 @@ public protocol FileServicing {
 // MARK: - Errors
 
 public enum FileServiceError: Error, Equatable {
+    case fileDataIsEmpty
+    case fileNotCreated
     case folderNotCreated
     case itemAlreadyExists
     case itemEmptyData

Library/Sources/Public/Services/FileService.swift

@@ -30,7 +30,7 @@ extension FileService: FileServicing {
     
     public func copyFile(from source: URL, to destination: URL) async throws (FileServiceError) {
         guard try await !isItemExists(at: destination) else {
-            throw FileServiceError.itemAlreadyExists
+            throw .itemAlreadyExists
         }
         
         var itemData: Data?
@@ -38,43 +38,59 @@ extension FileService: FileServicing {
         do {
             itemData = try Data(contentsOf: source)
         } catch {
-            throw FileServiceError.itemEmptyData
+            throw .itemEmptyData
         }
         
         do {
             try itemData?.write(to: destination, options: .atomic)
         } catch {
-            throw FileServiceError.itemNotCopied
+            throw .itemNotCopied
+        }
+    }
+    
+    public func createFile(at location: URL, with data: Data) async throws (FileServiceError) {
+        guard try await !isItemExists(at: location) else {
+            throw .itemAlreadyExists
+        }
+        
+        guard !data.isEmpty else {
+            throw .fileDataIsEmpty
+        }
+        
+        do {
+            try data.write(to: location, options: .atomic)
+        } catch {
+            throw .fileNotCreated
         }
     }
 
     public func createFolder(at location: URL) async throws (FileServiceError) {
         guard try await !isItemExists(at: location) else {
-            throw FileServiceError.itemAlreadyExists
+            throw .itemAlreadyExists
         }
         
         do {
             try fileManager.createDirectory(at: location, withIntermediateDirectories: true)
         } catch {
-            throw FileServiceError.folderNotCreated
+            throw .folderNotCreated
         }
     }
     
     public func deleteItem(at location: URL) async throws (FileServiceError) {
         guard try await isItemExists(at: location) else {
-            throw FileServiceError.itemNotExists
+            throw .itemNotExists
         }
         
         do {
             try fileManager.removeItem(at: location)
         } catch {
-            throw FileServiceError.itemNotDeleted
+            throw .itemNotDeleted
         }
     }
     
     public func isItemExists(at location: URL) async throws (FileServiceError) -> Bool {
         guard location.isFileURL else {
-            throw FileServiceError.itemNotFileURL
+            throw .itemNotFileURL
         }
         
         let filePath = location.pathString

Test/Sources/Cases/Public/Services/FileServiceTests.swift

@@ -35,7 +35,7 @@ struct FileServiceTests {
         // WHEN
         try await service.copyFile(from: source, to: destination)
 
-        // THENn
+        // THEN
         #expect(spy.actions.count == 1)
         
         let action = try #require(spy.actions.last)
@@ -57,6 +57,37 @@ struct FileServiceTests {
         #expect(spy.actions.isEmpty == true)
     }
     
+    @Test(arguments: zip([URL.someNewFile],
+                         [Data("some data goes here...".utf8)]))
+    func createFile(with location: URL, and data: Data) async throws {
+        // GIVEN
+        let service = service(action: .createFile(location, data))
+        
+        // WHEN
+        try await service.createFile(at: location, with: data)
+        
+        // THEN
+        #expect(spy.actions.count == 1)
+        
+        let action = try #require(spy.actions.last)
+        
+        #expect(action == .fileCreated(location, data))
+    }
+    
+    @Test(arguments: [FileServiceError.itemAlreadyExists, .fileDataIsEmpty, .fileNotCreated])
+    func createFile(throws error: FileServiceError) async throws {
+        // GIVEN
+        let service = service(action: .error(error))
+        
+        // WHEN
+        // THEN
+        await #expect(throws: error) {
+            try await service.createFile(at: .someNewFile, with: .init())
+        }
+        
+        #expect(spy.actions.isEmpty == true)
+    }
+    
     @Test(arguments: [URL.someNewFolder, .someNewFile])
     func createFolder(with location: URL) async throws {
         // GIVEN

Test/Sources/Helpers/Mocks/FileServiceMock.swift

@@ -64,6 +64,19 @@ extension FileServiceMock: FileServicing {
         }
     }
     
+    func createFile(at location: URL, with data: Data) async throws (FileServiceError) {
+        guard let nextAction else { return }
+        
+        switch nextAction {
+        case .error(let error):
+            throw error
+        case let .createFile(location, data):
+            try await spy?.createFile(at: location, with: data)
+        default:
+            break
+        }
+    }
+    
     func createFolder(at location: URL) async throws (FileServiceError) {
         guard let nextAction else { return }
         
@@ -127,6 +140,7 @@ private extension FileServiceMock {
 extension FileServiceMock {
     enum Action {
         case copyFile(URL, URL)
+        case createFile(URL, Data)
         case createFolder(URL)
         case deleteItem(URL)
         case error(FileServiceError)

Test/Sources/Helpers/Spies/FileServiceSpy.swift

@@ -21,6 +21,10 @@ extension FileServiceSpy: FileServicing {
         actions.append(.fileCopied(source, destination))
     }
     
+    func createFile(at location: URL, with data: Data) async throws (FileServiceError) {
+        actions.append(.fileCreated(location, data))
+    }
+    
     func createFolder(at location: URL) async throws (FileServiceError) {
         actions.append(.folderCreated(location))
     }
@@ -42,6 +46,7 @@ extension FileServiceSpy: FileServicing {
 
 extension FileServiceSpy {
     enum Action: Equatable {
+        case fileCreated(_ location: URL, _ data: Data)
         case fileCopied(_ source: URL, _ destination: URL)
         case folderCreated(_ location: URL)
         case itemDeleted(_ location: URL)