Modified test_walkthrough.py to avoid random failures when testing page 4.

When on page 4 test waits for the boards list to be loaded before selecting a board.

Author: konstantina

tests/walkthrough/test_walkthrough.py

@@ -38,8 +38,9 @@ def test_page_3(self):
 
     def test_page_4(self):
         """Test page 4"""
-        cb_cf_boards = self.get_element(By.CSS_SELECTOR, '#cb_cf_boards')
-        assert cb_cf_boards.is_displayed()
+        WebDriverWait(self.driver, 30).until(
+            expected_conditions.presence_of_element_located((By.CSS_SELECTOR, '#cb_cf_boards optgroup[label="Arduino"]'))
+        )
         self.execute_script(SELECT_BOARD_SCRIPT(TEST_BOARD), '$')
         cb_cf_ports = self.get_element(By.CSS_SELECTOR, '#cb_cf_ports')
         assert cb_cf_ports.is_displayed()