Java example source code file (CollectionSupplier.java)

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Java - Java tags/keywords

collection, collectionsupplier, integer, iterable, linkedlist, list, override, random, string, supplier, testcase, testexception, util

The CollectionSupplier.java Java example source code

/*
 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import java.lang.Exception;
import java.lang.Integer;
import java.lang.Iterable;
import java.lang.Override;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;

import org.testng.TestException;

import static org.testng.Assert.assertTrue;

import java.util.Collection;
import java.util.Collections;
import java.util.function.Supplier;

/**
 * @library
 * @summary A Supplier of test cases for Collection tests
 */
public final class CollectionSupplier<C extends Collection implements Supplier>> {

    private final Supplier<C>[] classes;
    private final int size;

    /**
     * A Collection test case.
     */
    public static final class TestCase<C extends Collection {

        /**
         * The name of the test case.
         */
        public final String name;

        /**
         * Unmodifiable reference collection, useful for comparisons.
         */
        public final List<Integer> expected;

        /**
         * A modifiable test collection.
         */
        public final C collection;

        /**
         * Create a Collection test case.
         *
         * @param name name of the test case
         * @param expected reference collection
         * @param collection the modifiable test collection
         */
        public TestCase(String name, C collection) {
            this.name = name;
            this.expected = Collections.unmodifiableList(
                Arrays.asList(collection.toArray(new Integer[0])));
            this.collection = collection;
        }

        @Override
        public String toString() {
            return name + " " + collection.getClass().toString();
        }
    }

    /**
     * Shuffle a list using a PRNG with known seed for repeatability
     *
     * @param list the list to be shuffled
     */
    public static <E> void shuffle(final List list) {
        // PRNG with known seed for repeatable tests
        final Random prng = new Random(13);
        final int size = list.size();
        for (int i = 0; i < size; i++) {
            // random index in interval [i, size)
            final int j = i + prng.nextInt(size - i);
            // swap elements at indices i & j
            final E e = list.get(i);
            list.set(i, list.get(j));
            list.set(j, e);
        }
    }

    /**
     * Create a {@code Supplier} that creates instances of specified collection
     * classes of specified length.
     *
     * @param classNames class names that implement {@code Collection}
     * @param size the desired size of each collection
     */
    public CollectionSupplier(Supplier<C>[] classes, int size) {
        this.classes = Arrays.copyOf(classes, classes.length);
        this.size = size;
    }

    @Override
    public Iterable<TestCase get() {
        final Collection<TestCase cases = new LinkedList<>();
        for (final Supplier<C> type : classes) {
            try {
                final Collection<Integer> empty = type.get();
                cases.add(new TestCase("empty", empty));

                final Collection<Integer> single = type.get();
                single.add(42);
                cases.add(new TestCase("single", single));

                final Collection<Integer> regular = type.get();
                for (int i = 0; i < size; i++) {
                    regular.add(i);
                }
                cases.add(new TestCase("regular", regular));

                final Collection<Integer> reverse = type.get();
                for (int i = size; i >= 0; i--) {
                    reverse.add(i);
                }
                cases.add(new TestCase("reverse", reverse));

                final Collection<Integer> odds = type.get();
                for (int i = 0; i < size; i++) {
                    odds.add((i * 2) + 1);
                }
                cases.add(new TestCase("odds", odds));

                final Collection<Integer> evens = type.get();
                for (int i = 0; i < size; i++) {
                    evens.add(i * 2);
                }
                cases.add(new TestCase("evens", evens));

                final Collection<Integer> fibonacci = type.get();
                int prev2 = 0;
                int prev1 = 1;
                for (int i = 0; i < size; i++) {
                    final int n = prev1 + prev2;
                    if (n < 0) { // stop on overflow
                        break;
                    }
                    fibonacci.add(n);
                    prev2 = prev1;
                    prev1 = n;
                }
                cases.add(new TestCase("fibonacci", fibonacci));

            // variants where the size of the backing storage != reported size
                // created by removing half of the elements
                final Collection<Integer> emptyWithSlack = type.get();
                emptyWithSlack.add(42);
                assertTrue(emptyWithSlack.remove(42));
                cases.add(new TestCase("emptyWithSlack", emptyWithSlack));

                final Collection<Integer> singleWithSlack = type.get();
                singleWithSlack.add(42);
                singleWithSlack.add(43);
                assertTrue(singleWithSlack.remove(43));
                cases.add(new TestCase("singleWithSlack", singleWithSlack));

                final Collection<Integer> regularWithSlack = type.get();
                for (int i = 0; i < (2 * size); i++) {
                    regularWithSlack.add(i);
                }
                assertTrue(regularWithSlack.removeIf((x) -> {
                    return x >= size;
                }));
                cases.add(new TestCase("regularWithSlack", regularWithSlack));

                final Collection<Integer> reverseWithSlack = type.get();
                for (int i = 2 * size; i >= 0; i--) {
                    reverseWithSlack.add(i);
                }
                assertTrue(reverseWithSlack.removeIf((x) -> {
                    return x < size;
                }));
                cases.add(new TestCase("reverseWithSlack", reverseWithSlack));

                final Collection<Integer> oddsWithSlack = type.get();
                for (int i = 0; i < 2 * size; i++) {
                    oddsWithSlack.add((i * 2) + 1);
                }
                assertTrue(oddsWithSlack.removeIf((x) -> {
                    return x >= size;
                }));
                cases.add(new TestCase("oddsWithSlack", oddsWithSlack));

                final Collection<Integer> evensWithSlack = type.get();
                for (int i = 0; i < 2 * size; i++) {
                    evensWithSlack.add(i * 2);
                }
                assertTrue(evensWithSlack.removeIf((x) -> {
                    return x >= size;
                }));
                cases.add(new TestCase("evensWithSlack", evensWithSlack));

                final Collection<Integer> fibonacciWithSlack = type.get();
                prev2 = 0;
                prev1 = 1;
                for (int i = 0; i < size; i++) {
                    final int n = prev1 + prev2;
                    if (n < 0) { // stop on overflow
                        break;
                    }
                    fibonacciWithSlack.add(n);
                    prev2 = prev1;
                    prev1 = n;
                }
                assertTrue(fibonacciWithSlack.removeIf((x) -> {
                    return x < 20;
                }));
                cases.add(new TestCase("fibonacciWithSlack",
                    fibonacciWithSlack));
            } catch (Exception failed) {
                throw new TestException(failed);
            }
        }

        return cases;
    }

}