def test_FileManager_ls_fail():
"""
The on_list_fail signal is emitted when a problem is encountered.
"""
fm = FileManager("/dev/ttyUSB0")
fm.on_list_fail = mock.MagicMock()
with mock.patch('mu.modes.base.microfs.ls', side_effect=Exception('boom')):
fm.ls()
fm.on_list_fail.emit.assert_called_once_with()
def test_FileManager_on_start_fails():
"""
When a thread signals it has started, but the serial connection cannot be
established, ensure that the on_list_fail is emitted to signal Mu can't get
the list of files from the board (because a connection cannot be
established).
"""
fm = FileManager("/dev/ttyUSB0")
fm.on_list_fail = mock.MagicMock()
mock_serial = mock.MagicMock(side_effect=Exception('BOOM!'))
with mock.patch('mu.modes.base.Serial', mock_serial):
fm.on_start()
mock_serial.assert_called_once_with("/dev/ttyUSB0",
115200,
timeout=1,
parity='N')
fm.on_list_fail.emit.assert_called_once_with()