Add doc for `click_component_from_menu` and make sure css is present in any case.

cms/djangoapps/contentstore/features/component_settings_editor_helpers.py

@@ -20,13 +20,20 @@ def click_new_component_button(step, component_button_css):
 
 @world.absorb
 def click_component_from_menu(instance_id, expected_css):
+    """
+    Creates a component from `instance_id`. For components with more
+    than one template, clicks on `elem_css` to create the new
+    component. Components with only one template are created as soon
+    as the user clicks the appropriate button, so we assert that the
+    expected component is present.
+    """
     elem_css = "a[data-location='%s']" % instance_id
     elements = world.css_find(elem_css)
     if len(elements) == 1:  # Multiple templates
         world.css_click(elem_css)
-        assert_equal(1, len(world.css_find(expected_css)))
     else:  # Single template
         assert(len(filter(lambda ele: ele.has_class('single_template'), elements)) == 1)
+    assert_equal(1, len(world.css_find(expected_css)))
 
 
 @world.absorb