Mocking ftplib.FTP for unit testing Python code

Question

I don\'t know why I\'m just not getting this, but I want to use mock in Python to test that my functions are calling functions in ftplib.FTP correctly. I\'ve simplified everythi

Answer 1

I suggest using pytest and pytest-mock.

from pytest_mock import mocker


def test_download_file(mocker):
    ftp_constructor_mock = mocker.patch('ftplib.FTP')
    ftp_mock = ftp_constructor_mock.return_value

    download_file('ftp.server.local', 'pub/files', 'wanted_file.txt')

    ftp_constructor_mock.assert_called_with('ftp.server.local')
    assert ftp_mock.login.called
    ftp_mock.cwd.assert_called_with('pub/files')