diff --git a/Tests/Library/Cases/Services/FileServiceTests.swift b/Tests/Library/Cases/Services/FileServiceTests.swift
new file mode 100644
index 0000000..092ee9c
--- /dev/null
+++ b/Tests/Library/Cases/Services/FileServiceTests.swift
@@ -0,0 +1,166 @@
+import Foundation
+import Testing
+
+@testable import ColibriLibrary
+
+struct FileServiceTests {
+    
+    // MARK: Properties
+    
+    private let spy = FileServiceSpy()
+
+    // MARK: Properties tests
+
+    @Test func currentFolder() async {
+        // GIVEN
+        let url: URL = .someCurrentFolder
+        
+        let service = FileServiceMock(currentFolder: url)
+
+        // WHEN
+        let folder = await service.currentFolder
+
+        // THEN
+        #expect(folder == url)
+        #expect(folder.isFileURL == true)
+    }
+    
+    // MARK: Functions
+    
+    @Test(arguments: [URL.someNewFolder, .someNewFile])
+    func createFolder(with url: URL) async throws {
+        // GIVEN
+        let service = FileServiceMock(
+            currentFolder: .someCurrentFolder,
+            action: .createFolder(url),
+            spy: spy
+        )
+
+        // WHEN
+        try await service.createFolder(at: url)
+        
+        // THEN
+        #expect(spy.isCreateFolderCalled == true)
+        #expect(spy.urlCalled == url)
+    }
+    
+    @Test(arguments: zip([URL.someExistingFolder, .someExistingFile, .someRandomURL],
+                         [FileServiceError.urlAlreadyExists, .urlAlreadyExists, .urlNotFileURL]))
+    func createFolder(
+        with url: URL,
+        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.createFolder(at: url)
+        }
+
+        #expect(spy.isCreateFolderCalled == false)
+        #expect(spy.urlCalled == nil)
+    }
+    
+    @Test(arguments: [URL.someNewFolder, .someNewFile])
+    func delete(with url: URL) async throws {
+        // GIVEN
+        let service = FileServiceMock(
+            currentFolder: .someCurrentFolder,
+            action: .delete(url),
+            spy: spy
+        )
+
+        // WHEN
+        try await service.delete(at: url)
+
+        // THEN
+        #expect(spy.isDeleteCalled == true)
+        #expect(spy.urlCalled == url)
+    }
+    
+    @Test(arguments: zip([URL.someNewFolder, .someNewFile, .someRandomURL],
+                         [FileServiceError.urlNotExists, .urlNotExists, .urlNotFileURL]))
+    func delete(
+        with url: URL,
+        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.delete(at: url)
+        }
+
+        #expect(spy.isDeleteCalled == false)
+        #expect(spy.urlCalled == nil)
+    }
+    
+    @Test(arguments: zip([URL.someExistingFolder, .someExistingFile, .someNewFolder, .someNewFile],
+                         [true, true, false, false]))
+    func exists(
+        with url: URL,
+        expects outcome: Bool
+    ) async throws {
+        // GIVEN
+        let service = FileServiceMock(
+            currentFolder: .someCurrentFolder,
+            action: .exists(url, outcome),
+            spy: spy
+        )
+
+        // WHEN
+        let result = try await service.exists(at: url)
+        
+        // THEN
+        #expect(result == outcome)
+
+        #expect(spy.isExistsAtCalled == true)
+        #expect(spy.urlCalled == url)
+    }
+    
+    @Test(arguments: zip([URL.someRandomURL], [FileServiceError.urlNotFileURL]))
+    func exists(
+        with url: URL,
+        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.exists(at: url)
+        }
+        
+        #expect(spy.isExistsAtCalled == false)
+        #expect(spy.urlCalled == nil)
+    }
+
+}
+
+// MARK: - URL+Constants
+
+private extension URL {
+    static let someCurrentFolder = URL(at: "/some/current/folder")
+    static let someExistingFolder = URL(at: "/some/existing/folder")
+    static let someExistingFile = URL(at: "/some/existing/file")
+    static let someNewFolder = URL(at: "/some/new/folder")
+    static let someNewFile = URL(at: "/some/new/file")
+    static let someRandomURL = URL(string: "some.random.url")!
+}
diff --git a/Tests/Library/Services/FileServiceTests.swift b/Tests/Library/Services/FileServiceTests.swift
deleted file mode 100644
index 8a53c0e..0000000
--- a/Tests/Library/Services/FileServiceTests.swift
+++ /dev/null
@@ -1,129 +0,0 @@
-import Foundation
-import Testing
-
-@testable import ColibriLibrary
-
-struct FileServiceTests {
-    
-    // MARK: Properties
-    
-    private let service: FileServicing
-    
-    // MARK: Initialisers
-    
-    init() {
-        self.service = FileService()
-    }
-
-    // MARK: Properties tests
-
-    @Test func currentFolder() async {
-        // GIVEN
-        // WHEN
-        let url = await service.currentFolder
-
-        // THEN
-        #expect(url == .someExistingFolder)
-        #expect(url.isFileURL == true)
-    }
-    
-    // MARK: Functions
-    
-    @Test(arguments: [URL.someNewFolder, .someNewFile])
-    func createFolder(with url: URL) async throws {
-        // GIVEN
-        if try await service.exists(at: url) {
-            try await service.delete(at: url)
-        }
-        
-        // WHEN
-        try await service.createFolder(at: url)
-        
-        // THEN
-        let result = try await service.exists(at: url)
-        
-        #expect(result == true)
-        
-        try await service.delete(at: url)
-    }
-    
-    @Test(arguments: zip([URL.someExistingFolder, .someExistingFile, .someRandomURL],
-                         [FileServiceError.urlAlreadyExists, .urlAlreadyExists, .urlNotFileURL]))
-    func createFolderThrows(
-        with url: URL,
-        expects error: FileServiceError
-    ) async throws {
-        // GIVEN
-        // WHEN
-        // THEN
-        await #expect(throws: error) {
-            try await service.createFolder(at: url)
-        }
-    }
-    
-    @Test(arguments: [URL.someNewFolder, .someNewFile])
-    func delete(with url: URL) async throws {
-        // GIVEN
-        if try await !service.exists(at: url) {
-            try await service.createFolder(at: url)
-        }
-
-        // WHEN
-        try await service.delete(at: url)
-
-        // THEN
-        let result = try await service.exists(at: url)
-        
-        #expect(result == false)
-    }
-    
-    @Test(arguments: zip([URL.someNewFolder, .someNewFile, .someRandomURL],
-                         [FileServiceError.urlNotExists, .urlNotExists, .urlNotFileURL]))
-    func deleteThrows(
-        with url: URL,
-        expects error: FileServiceError
-    ) async throws {
-        // GIVEN
-        // WHEN
-        // THEN
-        await #expect(throws: error) {
-            try await service.delete(at: url)
-        }
-    }
-    
-    @Test(arguments: zip([URL.someExistingFolder, .someExistingFile, .someNewFolder, .someNewFile],
-                         [true, true, false, false]))
-    func exists(
-        with url: URL,
-        expects outcome: Bool
-    ) async throws {
-        // GIVEN
-        // WHEN
-        let result = try await service.exists(at: url)
-        
-        // THEN
-        #expect(result == outcome)
-    }
-    
-    @Test func existsThrows() async throws {
-        // GIVEN
-        let url = URL.someRandomURL
-
-        // WHEN
-        // THEN
-        await #expect(throws: FileServiceError.urlNotFileURL) {
-            try await service.exists(at: url)
-        }
-    }
-
-}
-
-// MARK: - URL+Constants
-
-private extension URL {
-    static let someExistingFolder = URL(at: "/private/tmp")
-    static let someExistingFile = URL(at: "/etc/ssh/ssh_config")
-    static let someNewFolder = URL(at: "/private/tmp/folder")
-    static let someNewFile = URL(at: "/private/tmp/file.ext")
-    static let someRandomURL = URL(string: "https://some.random.url")!
-}