mocking_in_swift_network_protocol.swift

protocol NetworkClientProtocol {
    func executeRequest(request: URLRequest, completion: @escaping (Data?, Error?) -> Void)
}

extension URLSession: NetworkClientProtocol{
    /// this is where the real request happens
    func executeRequest(request: URLRequest, completion: @escaping (Data?, Error?) -> Void) {
        let task = dataTask(with: request) { (data, _, error) in
            completion(data, error)
        }
        task.resume()
    }
}