Introduction to JUnit

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JUnit is one of the most widely used testing frameworks for Java applications, particularly for web applications. As a QA tester specializing in web app testing, we use JUnit to automate unit tests and ensure that individual components of a web application work correctly before integrating them into the larger system. In this guide, we will introduce you to JUnit, its significance in automated web app testing, and its key features.

What is JUnit?

JUnit is an open-source framework designed for unit testing Java applications. It provides a structured approach to writing and executing test cases, making test automation more efficient. JUnit supports annotations, assertions, and test runners to facilitate effective test execution.

Why Use JUnit for Web App Testing?

Early Bug Detection: Helps identify issues in web app components before they reach production.
Automation and Efficiency: Reduces manual effort by automating unit tests for backend services, controllers, and API endpoints.
Integration with Build Tools: Works seamlessly with tools like Maven, Gradle, and Jenkins for continuous integration.
Better Code Quality: Encourages test-driven development (TDD) to ensure robust and reliable web applications.

Key Features of JUnit

Assertions: Validate expected and actual values in test cases.
Annotations: Simplify test execution with @BeforeEach, @Test and @AfterEach.
Test Suites: Group multiple test classes into a single test suite.
Parameterized Tests: Enables running the same test with different inputs.

JUnit Code Example for Web App Testing

Below is a simple example of a JUnit test for unlocking a Web Application from a Locked Screen state.

Example of JUnit Web App Test

package com.mqa.junit.tests;

import static org.junit.jupiter.api.Assertions.*;

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

class UnlockScreenTest {
	
	 private WebDriver driver;
	 
	 @BeforeEach
	    void setup() throws InterruptedException {
	        System.setProperty("webdriver.chrome.driver", "src/test/resources/driver/chromedriver");
	        driver = new ChromeDriver();
	        driver.manage().window().maximize();
	        driver.get("https://jahmalrichard.github.io/mqa-demo-test-app/pages-lock-screen.html");
	        // wait for 2 seconds (not recommended for testing purpose)
	         Thread.sleep(2000);
	    }
	
	 @Test
	    void unlockLockedScreenTest() throws InterruptedException {
         // get password element
	     WebElement passwordField = driver.findElement(By.id("pwd"));
	        passwordField.click();
	        passwordField.sendKeys("Test123!");
	     // get unlock button element   
	     WebElement unlockButton = driver.findElement(By.className("btn-primary"));
	        unlockButton.click();
	     // verify user is logged in
	        WebElement welcomeUser = driver.findElement(By.cssSelector(".profile-info.profile-info-no-role"));
	        assertTrue(welcomeUser.getText().contains("Hi, John Doe"), "User is logged in successfully");
	    }
	 
	 @AfterEach
	    void teardown() {
	        driver.quit();
	    }

}

Conclusion

JUnit is a powerful tool for unit testing web applications, providing a structured and efficient way to verify software functionality. By integrating JUnit into your development workflow, you can enhance code quality and detect potential bugs early in the software development lifecycle. In the next guide, we will walk you through Setting Up JUnit in Your Development Environment to ensure a smooth testing process.

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