Added lettuce tests for autoplay in videoalpha.

lms/djangoapps/courseware/features/videoalpha.feature

+Feature: Video Alpha component
+  As a student, I want to view course videos in LMS.
+
+  Scenario: Autoplay is enabled in LMS
+    Given the course has a Video component
+    Then when I view the video it has autoplay enabled

lms/djangoapps/courseware/features/videoalpha.py

+#pylint: disable=C0111
+
+from lettuce import world, step
+from lettuce.django import django_url
+from common import TEST_COURSE_NAME, TEST_SECTION_NAME, i_am_registered_for_the_course, section_location
+
+############### ACTIONS ####################
+
+
+@step('when I view the video it has autoplay enabled')
+def does_autoplay(step):
+    assert(world.css_find('.videoalpha')[0]['data-autoplay'] == 'True')
+
+
+@step('the course has a Video component')
+def view_videoalpha(step):
+    coursename = TEST_COURSE_NAME.replace(' ', '_')
+    i_am_registered_for_the_course(step, coursename)
+
+    # Make sure we have a videoalpha
+    add_videoalpha_to_course(coursename)
+    chapter_name = TEST_SECTION_NAME.replace(" ", "_")
+    section_name = chapter_name
+    url = django_url('/courses/edx/Test_Course/Test_Course/courseware/%s/%s' %
+                     (chapter_name, section_name))
+
+    world.browser.visit(url)
+
+
+def add_videoalpha_to_course(course):
+    template_name = 'i4x://edx/templates/videoalpha/default'
+    world.ItemFactory.create(parent_location=section_location(course),
+                             template=template_name,
+                             display_name='Video Alpha 1')