Why POM creates maintainable test code in Selenium Java - Test Execution Impact

Test Overview

This test verifies that the Page Object Model (POM) helps keep test code maintainable by separating page structure from test logic. It checks that changes in the page only require updates in one place, making tests easier to maintain.

Test Code - JUnit with Selenium WebDriver

Selenium Java

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;

// Page Object for Login Page
class LoginPage {
    private WebDriver driver;
    private By usernameField = By.id("username");
    private By passwordField = By.id("password");
    private By loginButton = By.id("loginBtn");

    public LoginPage(WebDriver driver) {
        this.driver = driver;
    }

    public void enterUsername(String username) {
        driver.findElement(usernameField).sendKeys(username);
    }

    public void enterPassword(String password) {
        driver.findElement(passwordField).sendKeys(password);
    }

    public void clickLogin() {
        driver.findElement(loginButton).click();
    }
}

// Test class
public class LoginTest {
    private WebDriver driver;
    private LoginPage loginPage;

    @BeforeEach
    public void setUp() {
        driver = new ChromeDriver();
        driver.get("https://example.com/login");
        loginPage = new LoginPage(driver);
    }

    @Test
    public void testValidLogin() {
        loginPage.enterUsername("user1");
        loginPage.enterPassword("pass123");
        loginPage.clickLogin();

        String expectedUrl = "https://example.com/dashboard";
        String actualUrl = driver.getCurrentUrl();
        assertEquals(expectedUrl, actualUrl, "User should be redirected to dashboard after login");
    }

    @AfterEach
    public void tearDown() {
        driver.quit();
    }
}

Execution Trace - 7 Steps

Step	Action	System State	Assertion	Result
1	Test starts and Chrome browser opens	Browser is open at https://example.com/login page	-	PASS
2	LoginPage object is created with driver	Page Object ready to interact with login page elements	-	PASS
3	Enter username 'user1' in username field using LoginPage method	Username field filled with 'user1'	-	PASS
4	Enter password 'pass123' in password field using LoginPage method	Password field filled with 'pass123'	-	PASS
5	Click login button using LoginPage method	Login button clicked, browser navigates to dashboard	-	PASS
6	Verify current URL is https://example.com/dashboard	Browser URL is https://example.com/dashboard	Assert current URL equals expected dashboard URL	PASS
7	Test ends and browser closes	Browser closed	-	PASS

Failure Scenario

Failing Condition: If the locator in LoginPage is incorrect or page structure changes without updating LoginPage

Execution Trace Quiz - 3 Questions

Why does using the LoginPage class help maintain test code?

A Because all locators and actions are in one place, so changes affect only this class

B Because it runs tests faster

C Because it removes the need for assertions

D Because it automatically fixes broken locators

Key Result

Using Page Object Model keeps locators and page actions in one place, so when the web page changes, only the page object needs updating, making tests easier to maintain and less error-prone.