Improve code clarity and error messages for css selection

common/djangoapps/terrain/browser.py

@@ -88,7 +88,6 @@ def initial_setup(server):
     """
     Launch the browser once before executing the tests.
     """
-    # from nose.tools import set_trace; set_trace()
     world.absorb(settings.SAUCE.get('SAUCE_ENABLED'), 'SAUCE_ENABLED')
 
     if not world.SAUCE_ENABLED:
@@ -166,15 +165,18 @@ def reset_databases(scenario):
     xmodule.modulestore.django.clear_existing_modulestores()
 
 
-# Uncomment below to trigger a screenshot on error
-# @after.each_scenario
+@after.each_scenario
 def screenshot_on_error(scenario):
     """
     Save a screenshot to help with debugging.
     """
     if scenario.failed:
-        world.browser.driver.save_screenshot('/tmp/last_failed_scenario.png')
-
+        try:
+            output_dir = '{}/log'.format(settings.TEST_ROOT)
+            image_name = '{}/{}.png'.format(output_dir, scenario.name.replace(' ', '_'))
+            world.browser.driver.save_screenshot(image_name)
+        except WebDriverException:
+            LOGGER.error('Could not capture a screenshot')
 
 @after.all
 def teardown_browser(total):

common/djangoapps/terrain/ui_helpers.py

@@ -5,7 +5,7 @@ from lettuce import world
 import time
 import platform
 from urllib import quote_plus
-from selenium.common.exceptions import WebDriverException
+from selenium.common.exceptions import WebDriverException, TimeoutException
 from selenium.webdriver.support import expected_conditions as EC
 from selenium.webdriver.common.by import By
 from selenium.webdriver.support.ui import WebDriverWait
@@ -54,8 +54,11 @@ def wait_for_present(css_selector, timeout=30):
     Throws an error if the wait_for time expires.
     Otherwise this method will return None
     """
-    WebDriverWait(driver=world.browser.driver,
-        timeout=60).until(EC.presence_of_element_located((By.CSS_SELECTOR, css_selector,)))
+    try:
+        WebDriverWait(driver=world.browser.driver,
+            timeout=60).until(EC.presence_of_element_located((By.CSS_SELECTOR, css_selector,)))
+    except TimeoutException:
+        raise TimeoutException("Timed out waiting for {} to be present.".format(css_selector))
 
 
 @world.absorb
@@ -65,8 +68,11 @@ def wait_for_visible(css_selector, timeout=30):
     Throws an error if the wait_for time expires.
     Otherwise this method will return None
     """
-    WebDriverWait(driver=world.browser.driver,
-        timeout=timeout).until(EC.visibility_of_element_located((By.CSS_SELECTOR, css_selector,)))
+    try:
+        WebDriverWait(driver=world.browser.driver,
+            timeout=timeout).until(EC.visibility_of_element_located((By.CSS_SELECTOR, css_selector,)))
+    except TimeoutException:
+        raise TimeoutException("Timed out waiting for {} to be visible.".format(css_selector))
 
 
 @world.absorb
@@ -76,8 +82,11 @@ def wait_for_invisible(css_selector, timeout=30):
     Throws an error if the wait_for time expires.
     Otherwise this method will return None
     """
-    WebDriverWait(driver=world.browser.driver,
-        timeout=timeout).until(EC.invisibility_of_element_located((By.CSS_SELECTOR, css_selector,)))
+    try:
+        WebDriverWait(driver=world.browser.driver,
+            timeout=timeout).until(EC.invisibility_of_element_located((By.CSS_SELECTOR, css_selector,)))
+    except TimeoutException:
+        raise TimeoutException("Timed out waiting for {} to be invisible.".format(css_selector))
 
 
 @world.absorb
@@ -89,8 +98,11 @@ def wait_for_clickable(css_selector, timeout=30):
     """
     # Sometimes the element is clickable then gets obscured.
     # In this case, pause so that it is not reported clickable too early
-    WebDriverWait(world.browser.driver,
-        timeout=timeout).until(EC.element_to_be_clickable((By.CSS_SELECTOR, css_selector,)))
+    try:
+        WebDriverWait(world.browser.driver,
+            timeout=timeout).until(EC.element_to_be_clickable((By.CSS_SELECTOR, css_selector,)))
+    except TimeoutException:
+        raise TimeoutException("Timed out waiting for {} to be clickable.".format(css_selector))
 
 
 @world.absorb
@@ -114,7 +126,8 @@ def css_click(css_selector, index=0, wait_time=30):
     This method will return True if the click worked.
     """
     wait_for_clickable(css_selector, timeout=wait_time)
-    assert world.css_find(css_selector)[index].visible
+    assert_true(world.css_find(css_selector)[index].visible,
+                msg="Element {}[{}] is present but not visible".format(css_selector, index))
 
     # Sometimes you can't click in the center of the element, as
     # another element might be on top of it. In this case, try
@@ -146,7 +159,8 @@ def css_click_at(css_selector, index=0, x_coord=10, y_coord=10, timeout=5):
     '''
     wait_for_clickable(css_selector, timeout=timeout)
     element = css_find(css_selector)[index]
-    assert element.visible
+    assert_true(element.visible,
+                msg="Element {}[{}] is present but not visible".format(css_selector, index))
 
     element.action_chains.move_to_element_with_offset(element._element, x_coord, y_coord)
     element.action_chains.click()
@@ -158,7 +172,7 @@ def id_click(elem_id):
     """
     Perform a click on an element as specified by its id
     """
-    css_click('#%s' % elem_id)
+    css_click('#{}'.format(elem_id))
 
 
 @world.absorb