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 Maven coordinates are:

<dependency>
  <groupId>nl.jqno.equalsverifier</groupId>
  <artifactId>equalsverifier</artifactId>
  <version>2.4</version>
  <scope>test</scope> </dependency>

For documentation, please see the project's website.

Pull requests are welcome! If you open one, please also register an issue or send a message to the Google Group, so we can discuss it.

Build

To build EqualsVerifier, you need Maven. Just call mvn clean verify from the command-line, and you're done. Alternatively, you can use any IDE with Maven support.

Project structure

src/

• nl.jqno.equalsverifier
  External API
• nl.jqno.equalsverifier.internal
  Classes internal to the operation of EqualsVerifier
• nl.jqno.equalsverifier.internal.checkers
  Checkers that perform EqualsVerifier's actual verifications
• nl.jqno.equalsverifier.internal.exceptions
  Internally used exceptions
• nl.jqno.equalsverifier.internal.prefabvalues
  Cache and factories for instances of all types
• nl.jqno.equalsverifier.internal.reflection Helpers for reflection-based tasks
• nl.jqno.equalsverifier.internal.util
  Various helpers

test/

• javax.persistence
  Annotations used by integration tests
• nl.jqno.equalsverifier
  Unit tests for specific subcomponents of EqualsVerifier
• nl.jqno.equalsverifier.coverage
  Code coverage tests, which fail if coverage is less than 100%
• nl.jqno.equalsverifier.integration.basic_contract
  Integration tests that cover the contract as stated in java.lang.Object's javadoc
• nl.jqno.equalsverifier.integration.extended_contract
  Integration tests that cover specific corner cases in the Java language, and other essential points that are discussed in other sources, such as Effective Java, but not in the javadoc
• nl.jqno.equalsverifier.integration.extra_features
  Integration tests that cover non-standard situations that EqualsVerifier supports
• nl.jqno.equalsverifier.integration.inheritance
  Integration tests that cover inheritance in equality relations
• nl.jqno.equalsverifier.integration.operational
  Integration tests that cover issues that don't pertain to equals or hashCode themselves, but to EqualsVerifier's operation
• nl.jqno.equalsverifier.testhelpers
  Utility classes for use in tests
• nl.jqno.equalsverifier.testhelpers.annotations
  Annotations used by unit tests and integration tests
• nl.jqno.equalsverifier.testhelpers.annotations.casefolding
  More annotations which would clash with other annotations because of casing
• nl.jqno.equalsverifier.testhelpers.types
  Various data classes for use in unit tests and integration tests
• nl.jqno.equalsverifier.util
  Unit tests for the reflection helpers

lib/

• equalsverifier-signedjar-test.jar A local Maven repository containing a signed jar, used to test potential ClassLoader issues
  Here's how to install a jar into it:
  

  mvn org.apache.maven.plugins:maven-install-plugin:2.3.1:install-file \
  
    -Dfile= -DgroupId= \
  
  -DartifactId= -Dversion= \
  
    -Dpackaging= -DcreateChecksum=true \
  
    -DlocalRepositoryPath=lib 

  The signed jar itself can be found in this repo.

Disclaimer

Copyright 2009-2017 Jan Ouwens