add lettuce test for displaying category if display_name is empty

cms/djangoapps/contentstore/features/component.feature

@@ -119,3 +119,12 @@ Feature: CMS.Component Adding
         Then I see the display name is "Text"
         When I change the display name to "I'm the Cuddliest!"
         Then I see the display name is "I'm the Cuddliest!"
+
+    Scenario: If a component has no display name, the category is displayed
+        Given I am in Studio editing a new unit
+        When I add a "Blank Advanced Problem" "Advanced Problem" component
+        Then I see the display name is "Blank Advanced Problem"
+        When I change the display name to ""
+        Then I see the display name is "problem"
+        When I unset the display name
+        Then I see the display name is "Blank Advanced Problem"

cms/djangoapps/contentstore/features/component.py

@@ -8,6 +8,8 @@
 from lettuce import world, step
 from nose.tools import assert_true, assert_in  # pylint: disable=E0611
 
+DISPLAY_NAME = "Display Name"
+
 
 @step(u'I add this type of single step component:$')
 def add_a_single_step_component(step):
@@ -165,5 +167,13 @@ def check_component_display_name(step, display_name):
 @step(u'I change the display name to "([^"]*)"')
 def change_display_name(step, display_name):
     world.edit_component_and_select_settings()
-    world.css_fill("ul.settings-list li:first-child input", display_name)
+    index = world.get_setting_entry_index(DISPLAY_NAME)
+    world.set_field_value(index, display_name)
+    world.save_component(step)
+
+
+@step(u'I unset the display name')
+def unset_display_name(step):
+    world.edit_component_and_select_settings()
+    world.revert_setting_entry(DISPLAY_NAME)
     world.save_component(step)

cms/djangoapps/contentstore/features/component_settings_editor_helpers.py

@@ -5,6 +5,7 @@ from lettuce import world
 from nose.tools import assert_equal, assert_in  # pylint: disable=E0611
 from terrain.steps import reload_the_page
 from common import type_in_codemirror
+from selenium.webdriver.common.keys import Keys
 
 
 @world.absorb
@@ -219,3 +220,18 @@ def get_setting_entry_index(label):
                 return index
         return None
     return world.retry_on_exception(get_index)
+
+
+@world.absorb
+def set_field_value(index, value):
+    """
+    Set the field to the specified value.
+
+    Note: we cannot use css_fill here because the value is not set
+    until after you move away from that field.
+    Instead we will find the element, set its value, then hit the Tab key
+    to get to the next field.
+    """
+    elem = world.css_find('div.wrapper-comp-setting input.setting-input')[index]
+    elem.value = value
+    elem.type(Keys.TAB)

cms/djangoapps/contentstore/features/problem-editor.py

@@ -7,7 +7,6 @@ from nose.tools import assert_equal, assert_true  # pylint: disable=E0611
 from common import type_in_codemirror, open_new_course
 from advanced_settings import change_value
 from course_import import import_file, go_to_import
-from selenium.webdriver.common.keys import Keys
 
 DISPLAY_NAME = "Display Name"
 MAXIMUM_ATTEMPTS = "Maximum Attempts"
@@ -53,7 +52,7 @@ def i_can_modify_the_display_name(_step):
     # Verifying that the display name can be a string containing a floating point value
     # (to confirm that we don't throw an error because it is of the wrong type).
     index = world.get_setting_entry_index(DISPLAY_NAME)
-    set_field_value(index, '3.4')
+    world.set_field_value(index, '3.4')
     verify_modified_display_name()
 
 
@@ -66,7 +65,7 @@ def my_display_name_change_is_persisted_on_save(step):
 @step('I can specify special characters in the display name')
 def i_can_modify_the_display_name_with_special_chars(_step):
     index = world.get_setting_entry_index(DISPLAY_NAME)
-    set_field_value(index, "updated ' \" &")
+    world.set_field_value(index, "updated ' \" &")
     verify_modified_display_name_with_special_chars()
 
 
@@ -141,7 +140,7 @@ def set_the_max_attempts(step, max_attempts_set):
     # on firefox with selenium, the behaviour is different.
     # eg 2.34 displays as 2.34 and is persisted as 2
     index = world.get_setting_entry_index(MAXIMUM_ATTEMPTS)
-    set_field_value(index, max_attempts_set)
+    world.set_field_value(index, max_attempts_set)
     world.save_component_and_reopen(step)
     value = world.css_value('input.setting-input', index=index)
     assert value != "", "max attempts is blank"
@@ -282,23 +281,9 @@ def verify_unset_display_name():
     world.verify_setting_entry(world.get_setting_entry(DISPLAY_NAME), DISPLAY_NAME, 'Blank Advanced Problem', False)
 
 
-def set_field_value(index, value):
-    """
-    Set the field to the specified value.
-
-    Note: we cannot use css_fill here because the value is not set
-    until after you move away from that field.
-    Instead we will find the element, set its value, then hit the Tab key
-    to get to the next field.
-    """
-    elem = world.css_find('div.wrapper-comp-setting input.setting-input')[index]
-    elem.value = value
-    elem.type(Keys.TAB)
-
-
 def set_weight(weight):
     index = world.get_setting_entry_index(PROBLEM_WEIGHT)
-    set_field_value(index, weight)
+    world.set_field_value(index, weight)
 
 
 def open_high_level_source():