How would you test a web application?

For comprehensive testing of a web application, I would use a multi-level approach that includes various types of testing:

• Functional testing:
  • User Interface (UI) testing: checking all elements, their layout, user interaction.
  • Business logic testing: verifying the correctness of all functions according to requirements.
  • Integration testing: checking interaction between different modules of the application and external systems.
• Non-functional testing:
  • Performance testing: assessing page load speed, server response, stability under load.
  • Security testing: checking for vulnerabilities (XSS, SQL Injection, CSRF, etc.), testing authentication and authorization.
  • Compatibility testing: testing the application across different browsers, operating systems, and devices (desktop, mobile).
  • Usability testing: evaluating the ease of use of the application for end-users.
• Data testing:
  • Data integrity verification: correctness of data saving, updating, and deletion.
  • Data migration testing (if necessary).
• Regression testing: Re-executing previously executed test scenarios to ensure no new defects appear after code changes.
• Test automation:
  • Automating the most priority and frequently repeated functional tests (UI, API).
  • Using frameworks like Selenium, Cypress, Playwright for UI automation.
  • Using tools like Postman, Rest-Assured for API automation.
  • Integrating automated tests into CI/CD pipelines.

Example of an automated test in Python using Selenium WebDriver:

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys

driver = webdriver.Chrome()  # Initialize WebDriver for Chrome
driver.get("https://example.com")  # Open the web application

# Find element by ID and input data
search_box = driver.find_element(By.ID, "search-input")
search_box.send_keys("test query")
search_box.send_keys(Keys.RETURN)  # Simulate pressing Enter

# Example of checking the page title after search
assert "Search Results" in driver.title

driver.quit()  # Close the browser

Example of a testing plan in table form:

Test Type	Testing Area	Test Scenario Examples	Tools/Frameworks
Functional (UI)	Registration form	- Entering correct/incorrect data <br>- Error message checks	Manual testing, Selenium/Cypress
Functional (Business)	Order placement	- Adding items to cart <br>- Applying discounts	Manual testing
Performance	Main page load	- Load time <br>- Max number of users	JMeter, LoadRunner
Security	Authorization	- SQL Injection checks in input fields <br>- Brute-force attacks	Burp Suite, OWASP ZAP
Compatibility	Display on different devices/browsers	- IE, Chrome, Firefox, Edge <br>- Mobile devices	BrowserStack, LambdaTest

Planning stages (defining testing scope, writing test scenarios/checklists) and analyzing testing results to prepare defect reports are also important. The Scrum methodology involves iterative testing within each sprint.