assertNotEquals in JUnit - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does assertNotEquals check in a JUnit test?

assertNotEquals checks that two values are NOT equal. If they are equal, the test fails.

beginner

How do you write assertNotEquals to check that 5 is not equal to 3?

Use assertNotEquals(5, 3); in your test method.

beginner

What happens if assertNotEquals compares two equal values?

The test fails and JUnit reports an assertion error because the values should not be equal.

intermediate

Can assertNotEquals be used to compare objects in JUnit?

Yes, it compares objects using their equals() method to check if they are not equal.

beginner

Why is assertNotEquals useful in testing?

It helps confirm that two values or objects are different, ensuring the code does not produce unwanted equal results.

What will happen if assertNotEquals(10, 10) is executed in a JUnit test?

A The test passes

B The test throws an exception unrelated to assertion

C The test is skipped

D The test fails

assertNotEquals expects values to be different. Since 10 equals 10, the test fails.

Which method does assertNotEquals use to compare objects?

A equals() method

B == operator

C hashCode() method

D toString() method

assertNotEquals uses the equals() method to check if objects are not equal.

What is the correct syntax to add a failure message in assertNotEquals?

A assertNotEquals(message, expected, actual);

B assertNotEquals(expected, actual, message);

C assertNotEquals(expected, message, actual);

D assertNotEquals(actual, expected, message);

The message comes first: assertNotEquals(String message, Object unexpected, Object actual).

Which JUnit version introduced assertNotEquals?

A JUnit 3

B JUnit 5

C JUnit 4

D JUnit 2

assertNotEquals was introduced in JUnit 4.

If you want to check two strings are not equal ignoring case, can you use assertNotEquals directly?

A Yes, it ignores case by default

B No, you must compare ignoring case manually

C Yes, but only in JUnit 5

D No, you must use assertNotSame instead

assertNotEquals uses equals() which is case sensitive. For ignoring case, compare manually.

Explain how assertNotEquals works in JUnit and when you would use it.

Think about confirming two things should not match in your test.

Describe the difference between assertEquals and assertNotEquals in JUnit.

One checks sameness, the other checks difference.