add Word Cloud acceptance tests

lms/djangoapps/courseware/features/word_cloud.feature

+Feature: World Cloud component
+  As a student, I want to view Word Cloud component in LMS.
+
+  Scenario: Word Cloud component in LMS is rendered with empty result
+  Given the course has a Word Cloud component
+  Then I view the word cloud and it has rendered
+  When I press the Save button
+  Then I see the empty result
+
+  Scenario: Word Cloud component in LMS is rendered with result
+  Given the course has a Word Cloud component
+  Then I view the word cloud and it has rendered
+  When I fill inputs
+  And I press the Save button
+  Then I see the result with words count
\ No newline at end of file

lms/djangoapps/courseware/features/word_cloud.py

+#pylint: disable=C0111
+
+from time import sleep
+
+from lettuce import world, step
+from lettuce.django import django_url
+from common import i_am_registered_for_the_course, section_location
+
+
+@step('I view the word cloud and it has rendered')
+def word_cloud_is_rendered(_step):
+    assert world.is_css_present('.word_cloud')
+
+
+@step('the course has a Word Cloud component')
+def view_word_cloud(_step):
+    coursenum = 'test_course'
+    i_am_registered_for_the_course(_step, coursenum)
+
+    add_word_cloud_to_course(coursenum)
+    chapter_name = world.scenario_dict['SECTION'].display_name.replace(
+        " ", "_")
+    section_name = chapter_name
+    url = django_url('/courses/%s/%s/%s/courseware/%s/%s' % (
+        world.scenario_dict['COURSE'].org,
+        world.scenario_dict['COURSE'].number,
+        world.scenario_dict['COURSE'].display_name.replace(' ', '_'),
+        chapter_name, section_name,)
+    )
+    world.browser.visit(url)
+
+
+@step('I press the Save button')
+def press_the_save_button(_step):
+    button_css = '.input_cloud_section input.save'
+    elem = world.css_find(button_css).first
+    world.css_has_text(button_css, elem)
+    world.css_click(button_css)
+
+
+@step('I see the empty result')
+def see_empty_result(_step):
+    assert (world.css_text('.your_words', 0) == '')
+
+
+@step('I fill inputs')
+def fill_inputs(_step):
+    input_css = '.input_cloud_section .input-cloud'
+    world.css_fill(input_css, 'text1', 0)
+
+    for index in range(1, 4):
+        world.css_fill('.input_cloud_section .input-cloud', 'text2', index)
+
+
+@step('I see the result with words count')
+def see_result(_step):
+    strong_css = '.your_words strong'
+    target_text = set([world.css_text(strong_css, i) for i in range(2)])
+    assert set(['text1', 'text2']) == target_text
+
+
+def add_word_cloud_to_course(course):
+    category = 'word_cloud'
+    world.ItemFactory.create(parent_location=section_location(course),
+                             category=category,
+                             display_name='Word Cloud')