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Elasticsearch subproject :test:framework
/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.test;
import java.io.IOException;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.not;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertThat;
import static org.junit.Assert.assertTrue;
/**
* Utility class that encapsulates standard checks and assertions around testing the equals() and hashCode()
* methods of objects that implement them.
*/
public class EqualsHashCodeTestUtils {
private static Object[] someObjects = new Object[] { "some string", Integer.valueOf(1), Double.valueOf(1.0) };
/**
* A function that makes a copy of its input argument
*/
public interface CopyFunction {
T copy(T t) throws IOException;
}
/**
* A function that creates a copy of its input argument that is different from its
* input in exactly one aspect (e.g. one parameter of a class instance should change)
*/
public interface MutateFunction {
T mutate(T t) throws IOException;
}
/**
* Perform common equality and hashCode checks on the input object
* @param original the object under test
* @param copyFunction a function that creates a deep copy of the input object
*/
public static void checkEqualsAndHashCode(T original, CopyFunction copyFunction) {
checkEqualsAndHashCode(original, copyFunction, null);
}
/**
* Perform common equality and hashCode checks on the input object
* @param original the object under test
* @param copyFunction a function that creates a deep copy of the input object
* @param mutationFunction a function that creates a copy of the input object that is different
* from the input in one aspect. The output of this call is used to check that it is not equal()
* to the input object
*/
public static void checkEqualsAndHashCode(T original, CopyFunction copyFunction, MutateFunction mutationFunction) {
try {
String objectName = original.getClass().getSimpleName();
assertFalse(objectName + " is equal to null", original.equals(null));
// TODO not sure how useful the following test is
assertFalse(objectName + " is equal to incompatible type", original.equals(ESTestCase.randomFrom(someObjects)));
assertTrue(objectName + " is not equal to self", original.equals(original));
assertThat(
objectName + " hashcode returns different values if called multiple times",
original.hashCode(),
equalTo(original.hashCode())
);
if (mutationFunction != null) {
T mutation = mutationFunction.mutate(original);
assertThat(objectName + " mutation should not be equal to original", mutation, not(equalTo(original)));
}
T copy = copyFunction.copy(original);
assertTrue(objectName + " copy is not equal to self", copy.equals(copy));
assertTrue(objectName + " is not equal to its copy", original.equals(copy));
assertTrue("equals is not symmetric", copy.equals(original));
assertThat(objectName + " hashcode is different from copies hashcode", copy.hashCode(), equalTo(original.hashCode()));
T secondCopy = copyFunction.copy(copy);
assertTrue("second copy is not equal to self", secondCopy.equals(secondCopy));
assertTrue("copy is not equal to its second copy", copy.equals(secondCopy));
assertThat("second copy's hashcode is different from original hashcode", copy.hashCode(), equalTo(secondCopy.hashCode()));
assertTrue("equals is not transitive", original.equals(secondCopy));
assertTrue("equals is not symmetric", secondCopy.equals(copy));
assertTrue("equals is not symmetric", secondCopy.equals(original));
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
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