JUnit Assert.assertEquals() Method Example

🎓 Top 15 Udemy Courses (80-90% Discount): My Udemy Courses - Ramesh Fadatare — All my Udemy courses are real-time and project oriented courses.

▶️ Subscribe to My YouTube Channel (178K+ subscribers): Java Guides on YouTube

▶️ For AI, ChatGPT, Web, Tech, and Generative AI, subscribe to another channel: Ramesh Fadatare on YouTube

< Previous Next >

JUnit 4 Tutorial

In this post, we will learn how to use the assertEquals() method with an example.

Check out JUnit 5 tutorials and examples at JUnit 5 Tutorial

In JUnit 5, all JUnit 4 assertion methods are moved to org.junit.jupiter.api.Assertions class.

void org.junit.Assert.assertEquals(Object expected, Object actual)

This method asserts that two objects are equal. If they are not, an AssertionError without a message is thrown. If expected and actual are null, they are considered equal.

Parameters:

expected - expected value actual - the value to check against expected

Assert.assertEquals() Method Example

Let's create a trimWhitespace() method to trim leading and trailing whitespace from the given String. We will create a JUnit test for the trimWhitespace() method to do unit testing.

import static org.junit.Assert.assertEquals;

import org.junit.Test;

public class AssertEqualsExamples {
 /**
  * Trim leading and trailing whitespace from the given {@code String}.
  * 
  * @param str
  *            the {@code String} to check
  * @return the trimmed {@code String}
  * @see java.lang.Character#isWhitespace
  */
 public static String trimWhitespace(final String str) {
     if (!(str != null && str.length() > 0)) {
           return str;
     }

     int beginIndex = 0;
     int endIndex = str.length() - 1;

     while (beginIndex <= endIndex && Character.isWhitespace(str.charAt(beginIndex))) {
          beginIndex++;
     }

     while (endIndex > beginIndex && Character.isWhitespace(str.charAt(endIndex))) {
          endIndex--;
     }

     return str.substring(beginIndex, endIndex + 1);
 }
 
 @Test
 public void testTrimWhitespace() {
     assertEquals(null, trimWhitespace(null));
     assertEquals("", trimWhitespace(""));
     assertEquals("", trimWhitespace(" "));
     assertEquals("", trimWhitespace("\t"));
     assertEquals("a", trimWhitespace(" a"));
     assertEquals("a", trimWhitespace("a "));
     assertEquals("a", trimWhitespace(" a "));
     assertEquals("a b", trimWhitespace(" a b "));
     assertEquals("a b  c", trimWhitespace(" a b  c "));
  }
}

Output:

Related JUnit Examples

JUnit Assert.assertArrayEquals() Method Example
JUnit Assert.assertEquals() Method Example
JUnit Assert.assertTrue() Method Example
JUnit Assert.assertFalse() Method Example
JUnit Assert.assertNull() Method Example
JUnit Assert.assertNotNull() Method Example
JUnit Assert.assertSame() Method Example
JUnit Assert.assertNotSame() Method Example
JUnit Assert.fail() Method Example

< Previous Next >

JUnit 4 Tutorial

My Top and Bestseller Udemy Courses. The sale is going on with a 70 - 80% discount. The discount coupon has been added to each course below:

Spring Boot + RabbitMQ Course - The Practical Guide

Java Guides

Search This Blog