Made a new command css_has_class that will safely check the class and get around stale elements

cms/djangoapps/contentstore/features/common.py

@@ -223,13 +223,7 @@ def shows_captions(step, show_captions):
     # Prevent cookies from overriding course settings
     world.browser.cookies.delete('hide_captions')
     if show_captions == 'does not':
-        attempt = 0
-        while attempt < 5:
-            try:
-                assert world.css_find('.video')[0].has_class('closed')
-            except:
-                attempt += 1
-        assert_true(attempt < 5, "There was a stale reference exception in accessing the class of the video")
+        assert world.css_has_class('.video', 'closed')
     else:
         assert world.is_css_not_present('.video.closed')
 

common/djangoapps/terrain/ui_helpers.py

@@ -182,6 +182,19 @@ def css_html(css_selector, index=0, max_attempts=5):
     return ''
 
 
+@world.absorb
+def css_has_class(css_selector, class_name, index=0, max_attempts=5):
+    attempt = 0
+    found = False
+    while attempt < max_attempts and not found:
+        try:
+            return world.css_find(css_selector)[index].has_class(class_name)
+            found = True
+        except:
+            attempt += 1
+    return False
+
+
 @world.absorb
 def css_visible(css_selector):
     assert is_css_present(css_selector), "{} is not present".format(css_selector)