EqualsVerifier

EqualsVerifier can be used in Java unit tests to verify whether the contract for the equals and hashCode methods in a class is met. The contracts are described in the Javadoc comments for the java.lang.Object class.

What's new?

Check out the Changelog!

Quick start

Get EqualsVerifier.

Maven users: EqualsVerifier is available from Maven Central. The groupId is nl.jqno.equalsverifier and the artifactId is equalsverifier. Make sure to use the latest version, and put it in the test scope.
Maven users who want to use version 1.0.2 or earlier: click here. Note that this method is now deprecated; use at your own risk.
ANT users: make sure the following jars are on the classpath:

objenesis-1.1.jar
cglib-nodep-2.2.jar
The EqualsVerifier jar. See Featured Downloads to download.

Use, as follows, in your unit test:

@Test
public void equalsContract() {
    EqualsVerifier.forClass(My.class).verify();
}

Or, if you prefer to use a getClass() check instead of an instanceof check in the body of your equals method:

@Test
public void equalsContract() {
    EqualsVerifier.forClass(My.class)
            .usingGetClass()
            .verify();
}

With some warnings suppressed:

@Test
public void equalsContract() {
    EqualsVerifier.forClass(My.class)
            .suppress(Warning.NONFINAL_FIELDS, Warning.NULL_FIELDS)
            .verify();
}

When EqualsVerifier detects a problem, it will explain what it thinks is wrong. In some cases (mostly when it needs more information), it will say what to do to fix the problem.

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EqualsVerifier

What's new?

Quick start

Help, I don't understand an error message!

Documentation