assertNotEquals in JUnit - Build an Automation Script

Verify that two different strings are not equal using assertNotEquals

Preconditions (2)

Step 1: Create two string variables with different values, for example, 'Hello' and 'World'

Step 2: Use assertNotEquals to verify that these two strings are not equal

✅ Expected Result: The test passes because the two strings are different

Automation Requirements - JUnit 5

Assertions Needed:

assertNotEquals to verify two values are not equal

Best Practices:

Use descriptive test method names

Keep tests independent and simple

Use static import for Assertions for cleaner code

Automated Solution

JUnit

import static org.junit.jupiter.api.Assertions.assertNotEquals;
import org.junit.jupiter.api.Test;

public class AssertNotEqualsTest {

    @Test
    void testStringsAreNotEqual() {
        String first = "Hello";
        String second = "World";
        assertNotEquals(first, second, "Strings should not be equal");
    }
}

This test class uses JUnit 5. We import assertNotEquals statically for cleaner code. The test method testStringsAreNotEqual creates two different strings, first and second. Then it calls assertNotEquals to check they are not the same. If they are different, the test passes. The message helps explain the assertion if it fails.

Common Mistakes - 3 Pitfalls

Using assertEquals instead of assertNotEquals

Not importing Assertions statically

Comparing variables with the same value

Bonus Challenge

Now add data-driven testing with 3 different pairs of strings to verify assertNotEquals works for all

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