Add a test for adding the WebExtension.

py/test/selenium/webdriver/firefox/ff_profile_tests.py

@@ -171,3 +171,20 @@ def test_autodetect_proxy_is_set_in_profile():
 
     profile.set_proxy(proxy)
     assert profile.default_preferences["network.proxy.type"] == ProxyType.AUTODETECT['ff_value']
+
+
+def test_that_we_can_add_a_webextension(capabilities, webserver):
+    extension_filename = 'webextension.xpi'
+    # TODO: This file should probably live in a common directory.
+    current_directory = os.path.dirname(os.path.realpath(__file__))
+    root_directory = os.path.join(current_directory, '..' , '..', '..', '..', '..')
+    data_directory = os.path.join(root_directory, 'javascript', 'node',
+                                  'selenium-webdriver', 'lib', 'test', 'data', 'firefox')
+    full_extension_filename = os.path.join(data_directory, extension_filename)
+
+    profile = FirefoxProfile()
+    profile.add_extension(full_extension_filename)
+
+    driver = Firefox(fcapabilities=capabilities, firefox_profile=profile)
+    driver.get(webserver.where_is('simpleTest.html'))
+    driver.find_element_by_id('webextensions-selenium-example')