During my Python & Selenium self-learning I came across a blocker while trying to access and select elements of a drop down.
Problem statement –
As a traveler, I want to select Business class for my flight on the Air NewZealand website , just to remind myself how atrociously expensive flying business class is .
Initial analysis –
Using Chrome Dev tools, I inspected the drop down and was expecting the various drop down entries to each have a unique id/index , so that I can select “business class” directly.
But lo-behold, the drop-down element is a <select> HTML that I had not worked with before. And each option was a <option> tag nested under the <select> tag.
Approach –
Potential ways I thought to solve this –
- Find the drop down using it’s id (
driver.find_element_by_id
) and find a way to iterate through the options based on their text . Likely to be brittle if the option text changes - Directly find the XPath of the option that I want and click it .
On further googling however, I found that the Selenium library offered an out of the box class to handle <select> web elements ! 🙂
This class has some handy dandy methods to retrieve all the options under the select tag , select them by value or index etc.
- select_by_index(index)
- Select the option at the given index. This is done by examing the “index” attribute of an element, and not merely by counting.
Args : - index – The option at this index will be selected
throws NoSuchElementException If there is no option with specisied index in SELECT
- select_by_value(value)
- Select all options that have a value matching the argument. That is, when given “foo” this would select an option like:
<option value=”foo”>Bar</option>
Args : - value – The value to match against
throws NoSuchElementException If there is no option with specisied value in SELECT
My solution –
Here is a simple Python script the uses the Select class and some of it’s method to solve the problem above.
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from selenium import webdriver | |
from selenium.webdriver.common.keys import Keys | |
from selenium.common.exceptions import NoSuchElementException | |
from selenium.common.exceptions import TimeoutException | |
import time | |
from selenium.webdriver.common.by import By | |
from selenium.webdriver.support.ui import WebDriverWait | |
from selenium.webdriver.support import expected_conditions as EC | |
from selenium.webdriver.support.select import Select | |
# for easy future changes and code maintainbility i have added all the locators and parameters like username/password at the top of the test | |
driver = webdriver.Chrome() | |
CONTINUE_BUTTON = (By.XPATH,'//*[@id="cms-search-panel-container"]/div/div/div/form/div[3]/div/button') | |
FLIGHT_CLASS_DROPDOWN = (By.ID,'serviceclass') | |
FLIGHT_CLASS_NAME = 'BUSINESS' | |
URL = 'https://www.airnewzealand.co.nz/home' | |
class AirNZ_flight_class: | |
def verify_flight_class_dropdown_value(self): | |
driver.maximize_window() | |
driver.get(URL) | |
# wait for the continue button to appear | |
continue_button = WebDriverWait(driver,10).until(EC.presence_of_element_located(CONTINUE_BUTTON)) | |
continue_button.click() | |
# wait for the fligh class dropdown to appear | |
flight_class_dropdown = WebDriverWait(driver,10).until(EC.presence_of_element_located(FLIGHT_CLASS_DROPDOWN)) | |
#select the drop down using the Select class imported from from selenium.webdriver.support.select | |
select = Select(flight_class_dropdown) | |
try: | |
# select an option from the drop down based on a value, i did not go for a index in case the index changes due to addition or removal of entries | |
select.select_by_value(FLIGHT_CLASS_NAME) | |
except(NoSuchElementException,TimeoutException) as e: | |
# fail the Test if the element can not be found or timeout occurs | |
print('Test failed, the flight class drop down could not be found ') | |
finally: | |
driver.quit() | |
test = AirNZ_flight_class() | |
test.verify_flight_class_dropdown_value() |
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