Fix the helpers for Select objects by wrapping them in promises

common/test/acceptance/tests/helpers.py

@@ -21,6 +21,7 @@ from pymongo import MongoClient, ASCENDING
 from openedx.core.lib.tests.assertions.events import assert_event_matches, is_matching_event, EventMatchTolerates
 from xmodule.partitions.partitions import UserPartition
 from xmodule.partitions.tests.test_partitions import MockUserPartitionScheme
+from selenium.common.exceptions import StaleElementReferenceException
 from selenium.webdriver.support.select import Select
 from selenium.webdriver.support.ui import WebDriverWait
 from selenium.webdriver.support import expected_conditions as EC
@@ -201,18 +202,36 @@ def enable_css_animations(page):
 def select_option_by_text(select_browser_query, option_text):
     """
     Chooses an option within a select by text (helper method for Select's select_by_visible_text method).
+
+    Wrap this in a Promise to prevent a StaleElementReferenceException
+    from being raised while the DOM is still being rewritten
     """
-    select = Select(select_browser_query.first.results[0])
-    select.select_by_visible_text(option_text)
+    def select_option(query, value):
+        try:
+            select = Select(query.first.results[0])
+            select.select_by_visible_text(value)
+            return True
+        except StaleElementReferenceException:
+            return False
+    EmptyPromise(lambda: select_option(select_browser_query, option_text), 'Selected option {}'.format(option_text)).fulfill()
 
 
 def get_selected_option_text(select_browser_query):
     """
     Returns the text value for the first selected option within a select.
-    """
-    select = Select(select_browser_query.first.results[0])
-    return select.first_selected_option.text
 
+    Wrap this in a Promise to prevent a StaleElementReferenceException
+    from being raised while the DOM is still being rewritten
+    """
+    def get_option(query):
+        try:
+            select = Select(select_browser_query.first.results[0])
+            return (True, select.first_selected_option.text)
+        except StaleElementReferenceException:
+            return (False, None)
+
+    text = Promise(lambda: get_option(select_browser_query), 'Retrieved selected option text').fulfill()
+    return text
 
 def get_options(select_browser_query):
     """