use wait_for_selector from utils module in test_dashboard_nav

notebook/tests/selenium/test_dashboard_nav.py

@@ -5,6 +5,7 @@ from selenium.webdriver.support.ui import WebDriverWait
 from selenium.webdriver.support import expected_conditions as EC
 
 from notebook.utils import url_path_join
+from notebook.tests.selenium.utils import wait_for_selector
 pjoin = os.path.join
 
 
@@ -40,7 +41,6 @@ def get_list_items(browser):
         'element': a,
     } for a in browser.find_elements_by_class_name('item_link')]
 
-
 def only_dir_links(browser):
     """Return only links that point at other directories in the tree
     
@@ -49,12 +49,6 @@ def only_dir_links(browser):
     return [i for i in items 
             if url_in_tree(browser, i['link']) and i['label'] != '..']
 
-
-def wait_for_selector(browser, selector, timeout=10):
-    wait = WebDriverWait(browser, timeout)
-    return wait.until(EC.visibility_of_element_located((By.CSS_SELECTOR, selector)))
-
-
 def test_items(authenticated_browser):
     visited_dict = {}
     # Going down the tree to collect links