nl.vpro.theory

Class ObjectTest<T>

java.lang.Object

nl.vpro.theory.ObjectTest<T>

Type Parameters:

T - Type of object which is tested

Direct Known Subclasses:

ComparableTest

public abstract class ObjectTest<T>
extends Object

Test for equals contract of objects. Borrowed from http://stackoverflow.com/questions/837484/junit-theory-for-hashcode-equals-contract

Author:

ernst-jan

Constructor Summary

Constructors

Constructor and Description
ObjectTest()

Method Summary

Modifier and Type	Method and Description
void	equalsIsConsistent(Object x, Object y) For any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
void	equalsIsReflexive(Object x) For any non-null reference value x, x.equals(x) should return true
void	equalsIsSymmetric(Object x, Object y) For any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
void	equalsIsTransitive(Object x, Object y, Object z) For any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
void	equalsReturnFalseOnNull(Object x) For any non-null reference value x, x.equals(null) should return false.
void	equalsWorks(Object x, Object y) Test that x.equals(y) where x and y are the same datapoint instance works.
void	hashCodeIsConsistentWithEquals(Object x, Object y) If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
void	hashCodeIsSelfConsistent(Object x) Whenever it is invoked on the same object more than once the hashCode() method must consistently return the same integer.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ObjectTest

public ObjectTest()

Method Detail

equalsIsReflexive

public final void equalsIsReflexive(Object x)

For any non-null reference value x, x.equals(x) should return true

equalsIsSymmetric

public final void equalsIsSymmetric(Object x,
                                    Object y)

For any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.

equalsIsTransitive

public final void equalsIsTransitive(Object x,
                                     Object y,
                                     Object z)

For any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.

equalsIsConsistent

public final void equalsIsConsistent(Object x,
                                     Object y)

For any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.

equalsReturnFalseOnNull

public final void equalsReturnFalseOnNull(Object x)

For any non-null reference value x, x.equals(null) should return false.

hashCodeIsSelfConsistent

public final void hashCodeIsSelfConsistent(Object x)

Whenever it is invoked on the same object more than once the hashCode() method must consistently return the same integer.

hashCodeIsConsistentWithEquals

public final void hashCodeIsConsistentWithEquals(Object x,
                                                 Object y)

If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.

equalsWorks

public final void equalsWorks(Object x,
                              Object y)

Test that x.equals(y) where x and y are the same datapoint instance works. User must provide datapoints that are not equal.