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.
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 the option at the given index. This is done by examing the “index” attribute of an element, and not merely by counting.
- index – The option at this index will be selected
throws NoSuchElementException If there is no option with specisied index in SELECT
- Select all options that have a value matching the argument. That is, when given “foo” this would select an option like:
- 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|
|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/div/button')|
|FLIGHT_CLASS_DROPDOWN = (By.ID,'serviceclass')|
|FLIGHT_CLASS_NAME = 'BUSINESS'|
|URL = 'https://www.airnewzealand.co.nz/home'|
|# wait for the continue button to appear|
|continue_button = WebDriverWait(driver,10).until(EC.presence_of_element_located(CONTINUE_BUTTON))|
|# 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)|
|# 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|
|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 ')|
|test = AirNZ_flight_class()|
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