Why patterns improve test quality in JUnit - Test Execution Impact

Test Overview

This test checks that using a test pattern (Page Object Model) helps keep tests clear and reliable by separating page details from test logic.

Test Code - JUnit

JUnit

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

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();
    }
}

public class LoginTest {

    @Test
    void testValidLogin() {
        WebDriver driver = new ChromeDriver();
        driver.get("https://example.com/login");

        LoginPage loginPage = new LoginPage(driver);
        loginPage.enterUsername("user1");
        loginPage.enterPassword("pass123");
        loginPage.clickLogin();

        WebElement welcomeMessage = driver.findElement(By.id("welcomeMsg"));
        assertTrue(welcomeMessage.isDisplayed(), "Welcome message should be visible after login");

        driver.quit();
    }
}

Execution Trace - 10 Steps

Step	Action	System State	Assertion	Result
1	Test starts	JUnit test runner initializes	-	PASS
2	Browser opens ChromeDriver	Chrome browser window opens at blank page	-	PASS
3	Navigates to https://example.com/login	Login page loads with username, password fields and login button	-	PASS
4	Creates LoginPage object with driver	Page object ready to interact with login page elements	-	PASS
5	Calls enterUsername("user1")	Username field found and filled with 'user1'	-	PASS
6	Calls enterPassword("pass123")	Password field found and filled with 'pass123'	-	PASS
7	Calls clickLogin()	Login button found and clicked, page processes login	-	PASS
8	Finds element with id 'welcomeMsg'	Welcome message element is present on page	Check if welcome message is displayed	PASS
9	Assert welcome message is visible	Welcome message visible to user	assertTrue(welcomeMessage.isDisplayed())	PASS
10	Closes browser and ends test	Browser closed, test finished	-	PASS

Failure Scenario

Failing Condition: If the login button locator changes and is not updated in LoginPage class

Execution Trace Quiz - 3 Questions

Why does using the LoginPage class improve test quality?

A It automatically fixes broken locators

B It makes the test run faster by skipping steps

C It separates page details from test logic making tests easier to read and maintain

D It removes the need for assertions

Key Result

Using test patterns like the Page Object Model keeps tests clean and easier to update when page details change, improving test quality and maintainability.