Finish Chapter 6

functional_tests/tests.py

 from django.test import LiveServerTestCase
 from selenium import webdriver
 from selenium.webdriver.common.keys import Keys
+from selenium.common.exceptions import WebDriverException
 import time
 
+MAX_WAIT = 10
+
 
 class NewVisitorTest(LiveServerTestCase):
     def setUp(self):
@@ -12,10 +15,18 @@ class NewVisitorTest(LiveServerTestCase):
     def tearDown(self):
         self.browser.quit()
 
-    def check_for_row_in_list_table(self, row_text):
-        table = self.browser.find_element_by_id('id_list_table')
-        rows = table.find_elements_by_tag_name('tr')
-        self.assertIn(row_text, [row.text for row in rows])
+    def wait_for_row_in_list_table(self, row_text):
+        start_time = time.time()
+        while True:
+            try:
+                table = self.browser.find_element_by_id('id_nothing')
+                rows = table.find_elements_by_tag_name('tr')
+                self.assertIn(row_text, [row.text for row in rows])
+                return
+            except (AssertionError, WebDriverException) as e:
+                if time.time() - start_time > MAX_WAIT:
+                    raise e
+                time.sleep(0.5)
 
     def test_can_start_a_list_and_retrieve_it_later(self):
         # Edith has heard about a cool new online to-do app. She goes
@@ -41,8 +52,7 @@ class NewVisitorTest(LiveServerTestCase):
         # When she hits enter, the page updates, and now the page lists
         # "1: Buy peacock feathers" as an item in a to-do list
         inputbox.send_keys(Keys.ENTER)
-        time.sleep(1)
-        self.check_for_row_in_list_table('1: Buy peacock feathers')
+        self.wait_for_row_in_list_table('1: Buy peacock feathers')
 
         # There is still a text box inviting her to add another item. She
         # enters "Use peacock feathers to make a fly"
@@ -50,11 +60,10 @@ class NewVisitorTest(LiveServerTestCase):
         inputbox = self.browser.find_element_by_id('id_new_item')
         inputbox.send_keys('Use peacock feathers to make a fly')
         inputbox.send_keys(Keys.ENTER)
-        time.sleep(1)
 
         # The page updates again, and now shows both items on her list
-        self.check_for_row_in_list_table('1: Buy peacock feathers')
-        self.check_for_row_in_list_table('2: Use peacock feathers to make a fly')
+        self.wait_for_row_in_list_table('1: Buy peacock feathers')
+        self.wait_for_row_in_list_table('2: Use peacock feathers to make a fly')
 
         # Edith wonders whether the site will remember her list. Then she sees
         # that the site has generated a unique URL for her -- there is some