from unittest.mock import Mock, patch from file_transfer.send_file import send_file @patch("socket.socket") @patch("builtins.open") def test_send_file_running_as_expected(file, sock): # ===== initialization ===== conn = Mock() sock.return_value.accept.return_value = conn, Mock() f = iter([1, None]) file.return_value.__enter__.return_value.read.side_effect = lambda _: next(f) # ===== invoke ===== send_file(filename="mytext.txt", testing=True) # ===== ensurance ===== sock.assert_called_once() sock.return_value.bind.assert_called_once() sock.return_value.listen.assert_called_once() sock.return_value.accept.assert_called_once() conn.recv.assert_called_once() file.return_value.__enter__.assert_called_once() file.return_value.__enter__.return_value.read.assert_called() conn.send.assert_called_once() conn.close.assert_called_once() sock.return_value.shutdown.assert_called_once() sock.return_value.close.assert_called_once()