Add new marker cross_browser

Author: birdsarah

setup.cfg

@@ -21,7 +21,8 @@ python_files = *_tests.py *_test.py test_*.py
 selenium_exclude_debug = html logs
 markers =
     integration: mark a test as an integration test - used for selenium tests
+    cross_browser: mark an integration test to run across multiple browsers (only has an effect when --driver=SauceLabs)
     js: mark a test as a javascript test
     examples: mark a test as an examples test
 
-addopts = --driver=Firefox --sensitive-url=None -rxs
+addopts = --driver=Firefox --sensitive-url=None -rxsw