a4-8.swift

class MockApiService: APIServiceProtocol {    
    var completePhotos: [Photo] = [Photo]() // Array of stubs
    var completeClosure: ((Bool, [Photo], APIError?) -> ())
    
    func fetchPopularPhoto(complete: @escaping (Bool, [Photo], APIError?) -> ()) {
        \\...\\
        completeClosure = complete
    }
    
    func fetchSuccess() {
        completeClosure( true, completePhotos, nil ) // Return stubs instead of empty array
    }
    \\....\\
}