src/test/java/org/apache/commons/lang3/tuple/PairTest.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
 *
 *      http://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.tuple;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertInstanceOf;
import static org.junit.jupiter.api.Assertions.assertNotEquals;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;

import java.util.Calendar;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Map.Entry;
import java.util.concurrent.ConcurrentHashMap;

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

/**
 * Test the Pair class.
 */
public class PairTest extends AbstractLangTest {

    @Test
    public void testAccept() {
        final Pair<String, String> pair1 = Pair.of("A", "D");
        final Pair<String, String> pair2 = Pair.of("B", "C");
        final Map<String, String> map = new HashMap<>();
        pair1.accept(map::put);
        pair2.accept(map::put);
        assertEquals("D", map.get("A"));
        assertEquals("C", map.get("B"));
        pair1.accept(map::put);
        pair2.accept(map::put);
        assertEquals("D", map.get("A"));
        assertEquals("C", map.get("B"));
    }

    @Test
    public void testApply() {
        final Pair<String, String> pair1 = Pair.of("A", "D");
        final Pair<String, String> pair2 = Pair.of("B", "C");
        final Map<String, String> map = new HashMap<>();
        assertNull(pair1.apply(map::put));
        assertNull(pair2.apply(map::put));
        assertEquals("D", map.get("A"));
        assertEquals("C", map.get("B"));
        assertEquals("D", pair1.apply(map::put));
        assertEquals("C", pair2.apply(map::put));
        assertEquals("D", map.get("A"));
        assertEquals("C", map.get("B"));
    }

    @Test
    public void testComparable1() {
        final Pair<String, String> pair1 = Pair.of("A", "D");
        final Pair<String, String> pair2 = Pair.of("B", "C");
        assertEquals(0, pair1.compareTo(pair1));
        assertTrue(pair1.compareTo(pair2) < 0);
        assertEquals(0, pair2.compareTo(pair2));
        assertTrue(pair2.compareTo(pair1) > 0);
    }

    @Test
    public void testComparable2() {
        final Pair<String, String> pair1 = Pair.of("A", "C");
        final Pair<String, String> pair2 = Pair.of("A", "D");
        assertEquals(0, pair1.compareTo(pair1));
        assertTrue(pair1.compareTo(pair2) < 0);
        assertEquals(0, pair2.compareTo(pair2));
        assertTrue(pair2.compareTo(pair1) > 0);
    }

    @Test
    public void testCompatibilityBetweenPairs() {
        final Pair<Integer, String> pair = ImmutablePair.of(0, "foo");
        final Pair<Integer, String> pair2 = MutablePair.of(0, "foo");
        assertEquals(pair, pair2);
        assertEquals(pair.hashCode(), pair2.hashCode());
        final HashSet<Pair<Integer, String>> set = new HashSet<>();
        set.add(pair);
        assertTrue(set.contains(pair2));

        pair2.setValue("bar");
        assertNotEquals(pair, pair2);
        assertNotEquals(pair.hashCode(), pair2.hashCode());
    }

    @Test
    public void testConcurrentHashMapEntry() {
        testMapEntry(new ConcurrentHashMap<>());
    }

    @Test
    public void testEmptyArrayGenerics() {
        final Pair<Integer, String>[] empty = Pair.emptyArray();
        assertEquals(0, empty.length);
    }

    @Test
    public void testEmptyArrayLength() {
        @SuppressWarnings("unchecked")
        final Pair<Integer, String>[] empty = (Pair<Integer, String>[]) Pair.EMPTY_ARRAY;
        assertEquals(0, empty.length);
    }

    @Test
    public void testFormattable_padded() {
        final Pair<String, String> pair = Pair.of("Key", "Value");
        assertEquals("         (Key,Value)", String.format("%1$20s", pair));
    }

    @Test
    public void testFormattable_simple() {
        final Pair<String, String> pair = Pair.of("Key", "Value");
        assertEquals("(Key,Value)", String.format("%1$s", pair));
    }

    @Test
    public void testHashMapEntry() {
        testMapEntry(new HashMap<>());
    }

    private void testMapEntry(final Map<Integer, String> map) {
        map.put(0, "foo");
        final Entry<Integer, String> entry = map.entrySet().iterator().next();
        final Pair<Integer, String> pair = ImmutablePair.of(0, "foo");
        assertEquals(pair, entry);
        assertEquals(pair.hashCode(), entry.hashCode());
        // LANG-1736:
        map.clear();
        map.put(0, "value1");
        map.put(1, "value2");
        map.entrySet().forEach(e -> {
            final Pair<Integer, String> p = ImmutablePair.of(e.getKey(), e.getValue());
            assertEquals(p, e);
            assertEquals(p.hashCode(), e.hashCode());
        });
    }

    @Test
    public void testOfNonNull() {
        assertThrows(NullPointerException.class, () -> Pair.ofNonNull(null, null));
        assertThrows(NullPointerException.class, () -> Pair.ofNonNull(null, "x"));
        assertThrows(NullPointerException.class, () -> Pair.ofNonNull("x", null));
        final Pair<String, String> pair = Pair.ofNonNull("x", "y");
        assertEquals("x", pair.getLeft());
        assertEquals("y", pair.getRight());
    }

    @Test
    public void testPairOfMapEntry() {
        final HashMap<Integer, String> map = new HashMap<>();
        map.put(0, "foo");
        final Entry<Integer, String> entry = map.entrySet().iterator().next();
        final Pair<Integer, String> pair = Pair.of(entry);
        assertEquals(entry.getKey(), pair.getLeft());
        assertEquals(entry.getValue(), pair.getRight());
    }

    @Test
    public void testPairOfObjects() {
        final Pair<Integer, String> pair = Pair.of(0, "foo");
        assertInstanceOf(ImmutablePair.class, pair);
        assertEquals(0, ((ImmutablePair<Integer, String>) pair).left.intValue());
        assertEquals("foo", ((ImmutablePair<Integer, String>) pair).right);
        final Pair<Object, String> pair2 = Pair.of(null, "bar");
        assertInstanceOf(ImmutablePair.class, pair2);
        assertNull(((ImmutablePair<Object, String>) pair2).left);
        assertEquals("bar", ((ImmutablePair<Object, String>) pair2).right);
        final Pair<?, ?> pair3 = Pair.of(null, null);
        assertNull(pair3.getLeft());
        assertNull(pair3.getRight());
    }

    @Test
    public void testToString() {
        final Pair<String, String> pair = Pair.of("Key", "Value");
        assertEquals("(Key,Value)", pair.toString());
    }

    @Test
    public void testToStringCustom() {
        final Calendar date = Calendar.getInstance();
        date.set(2011, Calendar.APRIL, 25);
        final Pair<String, Calendar> pair = Pair.of("DOB", date);
        assertEquals("Test created on " + "04-25-2011", pair.toString("Test created on %2$tm-%2$td-%2$tY"));
    }

}