How to resolve 'ImportError: No module named marionette_test'

Question

In my Python script I am trying to set some phone settings through Marionette driver. I am importing the following:

from marionette_driver import By
from marionette_driver import Wait
from marionette import Marionette

Then I am attempting to open a client session with the device:

client = Marionette('localhost', port=2828)
client.start_session()

However, I am receiving UnknownCommandException:

Traceback (most recent call last):
  File "xyz.py", line 30, in <module>
    client.start_session()
  File "/usr/local/lib/python2.7/dist-packages/marionette_driver/decorators.py", line 26, in _
    return func(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/marionette_driver/marionette.py", line 1243, in start_session
    body)
  File "/usr/local/lib/python2.7/dist-packages/marionette_driver/decorators.py", line 26, in _
    return func(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/marionette_driver/marionette.py", line 741, in _send_message
    self._handle_error(err)
  File "/usr/local/lib/python2.7/dist-packages/marionette_driver/marionette.py", line 765, in _handle_error
    raise errors.lookup(error)(message, stacktrace=stacktrace)
marionette_driver.errors.UnknownCommandException: WebDriver:NewSession

FYI, I am using marionette-driver 1.1.1

Any suggestion regarding resolving this issue will be much appreciated.

---

Edit on 10/26/2018

It is returning a different error message now:

$ python
Python 2.7.15rc1 (default, Apr 15 2018, 21:51:34) 
[GCC 7.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from marionette import Marionette
Traceback (most recent call last):
  File "./xyz.py", line 7, in <module>
    from marionette import Marionette
  File "/usr/local/lib/python2.7/dist-packages/marionette/__init__.py", line 7, in <module>
    from .marionette_test import (
ImportError: No module named marionette_test

Answer 1

This is probably due to an outdated driver as answered here: WebDriver Error New Session

• You can download the lastest from the Github Mozilla Repo.

If it is not Repo relate then it could be because .pyc files linger and python tries to use them first before recompiling.

• Basically you would find the relate .pyc files and remove then so the source is recompiled. Check this open bug for more info.

Thank you. Good day.