Fixed a few flaky selenium tests.

Many thanks go to David Burns (@AutomatedTester) for helping me understand
css selectors and pointing me towards the correct selenium methods.

django/contrib/admin/tests.py

@@ -51,8 +51,29 @@ class AdminSeleniumWebDriverTestCase(StaticLiveServerCase):
         Helper function that blocks until the element with the given tag name
         is found on the page.
         """
+        self.wait_for(tag_name, timeout)
+
+    def wait_for(self, css_selector, timeout=10):
+        """
+        Helper function that blocks until an css selector is found on the page.
+        """
+        from selenium.common.exceptions import NoSuchElementException, WebDriverException
+        from selenium.webdriver.common.by import By
+        from selenium.webdriver.support import expected_conditions as ec
         self.wait_until(
-            lambda driver: driver.find_element_by_tag_name(tag_name),
+            ec.presence_of_element_located((By.CSS_SELECTOR, css_selector)),
+            timeout
+        )
+
+    def wait_for_text(self, css_selector, text, timeout=10):
+        """
+        Helper function that blocks until the text is found in the css selector.
+        """
+        from selenium.webdriver.common.by import By
+        from selenium.webdriver.support import expected_conditions as ec
+        self.wait_until(
+            ec.text_to_be_present_in_element_value(
+                (By.CSS_SELECTOR, css_selector), text),
             timeout
         )
 

tests/admin_widgets/tests.py

@@ -993,9 +993,7 @@ class AdminRawIdWidgetSeleniumFirefoxTests(AdminSeleniumWebDriverTestCase):
 
         # The field now contains the selected band's id
         self.selenium.switch_to_window(main_window)
-        self.assertEqual(
+        self.wait_for_text('#id_main_band', '42')
-            self.selenium.find_element_by_id('id_main_band').get_attribute('value'),
-            '42')
 
         # Reopen the popup window and click on another band
         self.selenium.find_element_by_id('lookup_id_main_band').click()
@@ -1007,9 +1005,7 @@ class AdminRawIdWidgetSeleniumFirefoxTests(AdminSeleniumWebDriverTestCase):
 
         # The field now contains the other selected band's id
         self.selenium.switch_to_window(main_window)
-        self.assertEqual(
+        self.wait_for_text('#id_main_band', '98')
-            self.selenium.find_element_by_id('id_main_band').get_attribute('value'),
-            '98')
 
     def test_many_to_many(self):
         self.admin_login(username='super', password='secret', login_url='/')
@@ -1032,9 +1028,7 @@ class AdminRawIdWidgetSeleniumFirefoxTests(AdminSeleniumWebDriverTestCase):
 
         # The field now contains the selected band's id
         self.selenium.switch_to_window(main_window)
-        self.assertEqual(
+        self.wait_for_text('#id_supporting_bands', '42')
-            self.selenium.find_element_by_id('id_supporting_bands').get_attribute('value'),
-            '42')
 
         # Reopen the popup window and click on another band
         self.selenium.find_element_by_id('lookup_id_supporting_bands').click()
@@ -1046,9 +1040,7 @@ class AdminRawIdWidgetSeleniumFirefoxTests(AdminSeleniumWebDriverTestCase):
 
         # The field now contains the two selected bands' ids
         self.selenium.switch_to_window(main_window)
-        self.assertEqual(
+        self.wait_for_text('#id_supporting_bands', '42,98')
-            self.selenium.find_element_by_id('id_supporting_bands').get_attribute('value'),
-            '42,98')
 
 
 class AdminRawIdWidgetSeleniumChromeTests(AdminRawIdWidgetSeleniumFirefoxTests):
@@ -1087,10 +1079,8 @@ class RelatedFieldWidgetSeleniumFirefoxTests(AdminSeleniumWebDriverTestCase):
         save_button_css_selector = '.submit-row > input[type=submit]'
         self.selenium.find_element_by_css_selector(save_button_css_selector).click()
         self.selenium.switch_to_window(main_window)
-        # Wait up to 2 seconds for the new option to show up after clicking save in the popup.
+        # The field now contains the new user
-        self.selenium.implicitly_wait(2)
+        self.wait_for('#id_user option[value="newuser"]')
-        self.selenium.find_element_by_css_selector('#id_user option[value=newuser]')
-        self.selenium.implicitly_wait(0)
 
         # Go ahead and submit the form to make sure it works
         self.selenium.find_element_by_css_selector(save_button_css_selector).click()