RFC: migrate to cucumber

tests/features/python/authentication.py

@@ -0,0 +1,13 @@
+from behave import *
+
+@given('an anonymous user')
+def step_impl(context):
+    pass
+
+@when('an existing user')
+def step_impl(context):
+    assert True is not False
+
+@then('I sign up with a valid email and password')
+def step_impl(context):
+    assert context.failed is False