assertEquals in JUnit - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does assertEquals do in JUnit?

assertEquals checks if two values are the same. If they are not, the test fails.

beginner

How do you write assertEquals to compare expected and actual values?

Use assertEquals(expected, actual). The first value is what you expect, the second is what your code gives.

beginner

What happens if assertEquals fails during a test?

The test stops and reports failure. It shows the expected and actual values to help find the problem.

intermediate

Can assertEquals compare objects in JUnit?

Yes, it compares objects using their equals() method. Objects must override equals() properly for correct comparison.

beginner

Why is the order of parameters important in assertEquals(expected, actual)?

The order matters because failure messages show expected first, then actual. This helps understand test results clearly.

What is the correct order of parameters in assertEquals?

A actual only

B actual, expected

C expected, actual

D expected only

The first parameter is the expected value, the second is the actual value from the code.

What happens if assertEquals finds values are not equal?

A Test fails and stops

B Test ignores the difference

C Test passes

D Test retries automatically

The test fails immediately and reports the difference.

Which method does assertEquals use to compare objects?

A compareTo()

B hashCode()

C toString()

D equals()

It uses the equals() method to check if objects are equal.

Which of these is a valid assertEquals statement in JUnit?

A assertEquals()

B assertEquals(5, calculateSum())

C assertEquals(5)

D assertEquals(calculateSum(), 5)

Expected value first, then actual value from the method.

Why should you use assertEquals instead of assertTrue(a == b)?

A assertEquals gives clearer failure messages

B assertTrue is faster

C assertEquals ignores differences

D assertTrue works only for strings

assertEquals shows expected and actual values on failure, making debugging easier.

Explain how assertEquals works in JUnit and why the order of parameters matters.

Think about how test results help you find bugs.

Describe how assertEquals compares objects and what you need to ensure for correct comparison.

Consider how Java compares two objects by default.