Marionette Harness

5.0.0 verified Sat May 09 auth: no python

Marionette Harness is a Python test automation framework for Firefox's Marionette protocol, used for Gecko-based browser automation. The current version is 5.0.0, released with support for Python 3 and asynchronous test execution. Release cadence is irregular, tied to Firefox releases.

pip install marionette-harness

Common errors

error ModuleNotFoundError: No module named 'marionette' ↓

cause Trying to import the old 'marionette' package instead of 'marionette_harness'.

fix

Use 'from marionette_harness import ...' instead.

error ImportError: cannot import name 'Marionette' from 'marionette_harness' ↓

cause Marionette client class is in the separate 'marionette_driver' package, not in 'marionette_harness'.

fix

Install marionette-driver and import from 'marionette_driver'.

error Error: The browser is not responding. The connection to Marionette server is lost. ↓

cause Firefox is not launched with Marionette enabled (--marionette flag) or geckodriver is missing.

fix

Launch Firefox with --marionette flag or ensure geckodriver is installed and in PATH.

Warnings

breaking In version 5.0.0, the package was renamed from 'marionette' to 'marionette-harness' on PyPI. Old import paths (e.g., 'from marionette import ...') no longer work. ↓

fix Ensure your installation uses 'marionette-harness' and imports from 'marionette_harness'.

deprecated Python 2 support is dropped; the harness now requires Python 3.6+. ↓

fix Upgrade to Python 3 environment.

gotcha The marionette-driver package (imported via 'from marionette_driver import Marionette') is a separate dependency and must be installed explicitly or via marionette-harness[geckodriver]. ↓

fix Install marionette_driver: pip install marionette-driver, or use the optional dependency.

Install

pip install 'marionette-harness[geckodriver]'

Imports

Marionette
wrong
```
from marionette import Marionette
```
correct
```
from marionette_driver import Marionette
```
Marionette driver is a separate package marionette_driver, not marionette

MarionetteTestCase

from marionette_harness import MarionetteTestCase

MarionetteHarness

from marionette_harness import MarionetteHarness

marionette
wrong
```
import marionette
```
correct
```
import marionette_harness.runner as runner
```
Top-level 'marionette' package does not exist; the harness is marionette_harness

Quickstart

Basic test using MarionetteTestCase. Requires Firefox with Marionette enabled (--marionette flag).

from marionette_driver import Marionette
from marionette_harness import MarionetteTestCase

class TestBasic(MarionetteTestCase):
    def test_navigate(self):
        self.marionette.navigate('https://example.com')
        self.assertIn('Example', self.marionette.title)

if __name__ == '__main__':
    from marionette_harness import MarionetteHarness
    MarionetteHarness().run_tests()