HashCodeBuilderAndEqualsBuilderTest.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.lang3.builder;

import static org.junit.jupiter.api.Assertions.assertEquals;

import org.apache.commons.lang3.AbstractLangTest;
import org.junit.jupiter.api.Test;

/**
 * Tests {@link org.apache.commons.lang3.builder.HashCodeBuilder} and
 * {@link org.apache.commons.lang3.builder.EqualsBuilderTest} to ensure that equal
 * objects must have equal hash codes.
 */
class HashCodeBuilderAndEqualsBuilderTest extends AbstractLangTest {

    static class AllTransientFixture {
        transient int i;
        transient char c;
        transient String string;
        transient short s;

        AllTransientFixture(final int i, final char c, final String string, final short s) {
            this.i = i;
            this.c = c;
            this.string = string;
            this.s = s;
        }
    }

    static class SubAllTransientFixture extends AllTransientFixture {
        transient String tString;

        SubAllTransientFixture(final int i, final char c, final String string, final short s, final String tString) {
            super(i, c, string, s);
            this.tString = tString;
        }
    }

    static class SubTestFixture extends TestFixture {
        transient String tString;

        SubTestFixture(final int i, final char c, final String string, final short s, final String tString) {
            super(i, c, string, s);
            this.tString = tString;
        }
    }

    static class TestFixture {
        int i;
        char c;
        String string;
        short s;

        TestFixture(final int i, final char c, final String string, final short s) {
            this.i = i;
            this.c = c;
            this.string = string;
            this.s = s;
        }
    }

    /**
     * Asserts that if {@code lhs} equals {@code rhs}
     * then their hash codes MUST be identical.
     *
     * @param lhs The Left-Hand-Side of the equals test
     * @param rhs The Right-Hand-Side of the equals test
     * @param testTransients whether to test transient fields
     */
    private void assertEqualsAndHashCodeContract(final Object lhs, final Object rhs, final boolean testTransients) {
        if (EqualsBuilder.reflectionEquals(lhs, rhs, testTransients)) {
            // test a couple of times for consistency.
            assertEquals(HashCodeBuilder.reflectionHashCode(lhs, testTransients), HashCodeBuilder.reflectionHashCode(rhs, testTransients));
            assertEquals(HashCodeBuilder.reflectionHashCode(lhs, testTransients), HashCodeBuilder.reflectionHashCode(rhs, testTransients));
            assertEquals(HashCodeBuilder.reflectionHashCode(lhs, testTransients), HashCodeBuilder.reflectionHashCode(rhs, testTransients));
        }
    }

    @Test
    void testFixture() {
        testFixture(false);
    }

    private void testFixture(final boolean testTransients) {
        assertEqualsAndHashCodeContract(new TestFixture(2, 'c', "Test", (short) 2), new TestFixture(2, 'c', "Test", (short) 2), testTransients);
        assertEqualsAndHashCodeContract(
            new AllTransientFixture(2, 'c', "Test", (short) 2),
            new AllTransientFixture(2, 'c', "Test", (short) 2),
            testTransients);
        assertEqualsAndHashCodeContract(
            new SubTestFixture(2, 'c', "Test", (short) 2, "Same"),
            new SubTestFixture(2, 'c', "Test", (short) 2, "Same"),
            testTransients);
        assertEqualsAndHashCodeContract(
            new SubAllTransientFixture(2, 'c', "Test", (short) 2, "Same"),
            new SubAllTransientFixture(2, 'c', "Test", (short) 2, "Same"),
            testTransients);

    }

    @Test
    void testFixtureWithTransients() {
        testFixture(true);
    }

    @Test
    void testInteger() {
        testInteger(false);
    }

    private void testInteger(final boolean testTransients) {
        final Integer i1 = Integer.valueOf(12345);
        final Integer i2 = Integer.valueOf(12345);
        assertEqualsAndHashCodeContract(i1, i2, testTransients);
    }

    @Test
    void testIntegerWithTransients() {
        testInteger(true);
    }

    @Test
    void testRetention() throws Exception {
        // The following should not retain memory.
        for (int i = 0; i < Integer.getInteger("testRecursive", 10_000); i++) {
            final Class<?> clazz = TestClassBuilder.defineSimpleClass(getClass().getPackage().getName(), i);
            assertEqualsAndHashCodeContract(clazz.newInstance(), clazz.newInstance(), false);
        }
    }

}