Package nl.jqno.equalsverifier

Class EqualsVerifier

java.lang.Object
nl.jqno.equalsverifier.EqualsVerifier
public final class EqualsVerifier extends Object
EqualsVerifier can be used in 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 Object.equals(Object) and Object.hashCode()

To get started, use EqualsVerifier as follows:

EqualsVerifier.forClass(My.class).verify();

Or, if that's too strict:

EqualsVerifier.simple().forClass(My.class).verify();

For more information, see the documentation at http://www.jqno.nl/equalsverifier

  • Method Details

    • configure

      public static ConfiguredEqualsVerifier configure()
      Creates a configuration object that can be reused with EqualsVerifier for multiple classes. It has a fluent API.

      Save the configuration in a variable of type EqualsVerifierApi and call forClass(Class) on it for each class whose equals and hashCode must be verified.

      Returns:
      A reusable configuration object with a fluent API.

    • simple

      public static ConfiguredEqualsVerifier simple()
      Creates a configuration object that is pre-configured so that it can be used with most IDE-generated equals and hashCode methods without any further configuration.
      Returns:
      A reusable configuration object with a fluent API.

    • forClass

      public static <T> SingleTypeEqualsVerifierApi<T> forClass(Class<T> type)
      Factory method. For general use.
      Type Parameters:
      T - The type.
      Parameters:
      type - The class for which the equals method should be tested.
      Returns:
      A fluent API for EqualsVerifier.

    • forClasses

      public static MultipleTypeEqualsVerifierApi forClasses(Iterable<Class<?>> classes)
      Factory method. For general use.
      Parameters:
      classes - An iterable containing the classes for which equals method should be tested.
      Returns:
      A fluent API for EqualsVerifier.

    • forClasses

      public static MultipleTypeEqualsVerifierApi forClasses(Class<?> first, Class<?> second, Class<?>... more)
      Factory method. For general use.
      Parameters:
      first - A class for which the equals method should be tested.
      second - Another class for which the equals method should be tested.
      more - More classes for which the equals method should be tested.
      Returns:
      A fluent API for EqualsVerifier.

    • forPackage

      public static MultipleTypeEqualsVerifierApi forPackage(String packageName)
      Factory method. For general use.

      Note that this operation may be slow. If the test is too slow, use forClasses(Class, Class, Class...) instead.

      Parameters:
      packageName - A package for which each class's equals should be tested.
      Returns:
      A fluent API for EqualsVerifier.

    • forPackage

      public static MultipleTypeEqualsVerifierApi forPackage(String packageName, boolean scanRecursively)
      Factory method. For general use.

      Note that this operation may be slow. If the test is too slow, use forClasses(Class, Class, Class...) instead.

      Parameters:
      packageName - A package for which each class's equals should be tested.
      scanRecursively - true to scan all sub-packages
      Returns:
      A fluent API for EqualsVerifier.

    • forPackage

      public static MultipleTypeEqualsVerifierApi forPackage(String packageName, Class<?> mustExtend)
      Factory method. For general use.

      Note that this operation may be slow. If the test is too slow, use forClasses(Class, Class, Class...) instead.

      Also note that if mustExtend is given, and it exists within packageName, it will NOT be included.

      Parameters:
      packageName - A package for which each class's equals should be tested.
      mustExtend - if not null, returns only classes that extend or implement this class.
      Returns:
      A fluent API for EqualsVerifier.

    • forRelaxedEqualExamples

      @SafeVarargs public static <T> RelaxedEqualsVerifierApi<T> forRelaxedEqualExamples(T first, T second, T... more)
      Factory method. Asks for a list of equal, but not identical, instances of T.

      For use when T is a class which has relaxed equality rules. This happens when two instances of T are equal even though the its internal state is different.

      This could happen, for example, in a Rational class that doesn't normalize: new Rational(1, 2).equals(new Rational(2, 4)) would return true.

      Using this factory method requires that RelaxedEqualsVerifierApi.andUnequalExamples(Object, Object...) be called to supply a list of unequal instances of T.

      This method automatically suppresses Warning.ALL_FIELDS_SHOULD_BE_USED.

      Type Parameters:
      T - the type.
      Parameters:
      first - An instance of T.
      second - Another instance of T, which is equal, but not identical, to first.
      more - More instances of T, all of which are equal, but not identical, to one another and to first and second.
      Returns:
      A fluent API for a more relaxed EqualsVerifier.