common/collect/ImmutableMapTest.java

/*
 * Copyright (C) 2008 The Guava Authors
 *
 * Licensed 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 com.google.common.collect;

import static com.google.common.collect.testing.Helpers.mapEntry;
import static com.google.common.testing.SerializableTester.reserialize;
import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Equivalence;
import com.google.common.collect.ImmutableMap.Builder;
import com.google.common.collect.testing.AnEnum;
import com.google.common.collect.testing.CollectionTestSuiteBuilder;
import com.google.common.collect.testing.ListTestSuiteBuilder;
import com.google.common.collect.testing.MapTestSuiteBuilder;
import com.google.common.collect.testing.TestStringMapGenerator;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.MapFeature;
import com.google.common.collect.testing.google.MapGenerators.ImmutableMapCopyOfEntriesGenerator;
import com.google.common.collect.testing.google.MapGenerators.ImmutableMapCopyOfEnumMapGenerator;
import com.google.common.collect.testing.google.MapGenerators.ImmutableMapCopyOfGenerator;
import com.google.common.collect.testing.google.MapGenerators.ImmutableMapEntryListGenerator;
import com.google.common.collect.testing.google.MapGenerators.ImmutableMapGenerator;
import com.google.common.collect.testing.google.MapGenerators.ImmutableMapKeyListGenerator;
import com.google.common.collect.testing.google.MapGenerators.ImmutableMapUnhashableValuesGenerator;
import com.google.common.collect.testing.google.MapGenerators.ImmutableMapValueListGenerator;
import com.google.common.collect.testing.google.MapGenerators.ImmutableMapValuesAsSingletonSetGenerator;
import com.google.common.testing.CollectorTester;
import com.google.common.testing.EqualsTester;
import com.google.common.testing.NullPointerTester;
import java.io.ByteArrayOutputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.AbstractMap;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.EnumMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collector;
import java.util.stream.Stream;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tests for {@link ImmutableMap}.
 *
 * @author Kevin Bourrillion
 * @author Jesse Wilson
 */
@GwtCompatible(emulated = true)
@SuppressWarnings("AlwaysThrows")
public class ImmutableMapTest extends TestCase {

  @GwtIncompatible // suite
  public static Test suite() {
    TestSuite suite = new TestSuite();
    suite.addTestSuite(ImmutableMapTest.class);

    suite.addTest(
        MapTestSuiteBuilder.using(new ImmutableMapGenerator())
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS,
                CollectionFeature.KNOWN_ORDER,
                MapFeature.REJECTS_DUPLICATES_AT_CREATION,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .named("ImmutableMap")
            .createTestSuite());

    suite.addTest(
        MapTestSuiteBuilder.using(
                new TestStringMapGenerator() {
                  @Override
                  protected Map<String, String> create(Entry<String, String>[] entries) {
                    ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
                    builder.putAll(Arrays.asList(entries));
                    return builder.buildJdkBacked();
                  }
                })
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS,
                CollectionFeature.KNOWN_ORDER,
                MapFeature.REJECTS_DUPLICATES_AT_CREATION,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .named("ImmutableMap [JDK backed]")
            .createTestSuite());

    suite.addTest(
        MapTestSuiteBuilder.using(new ImmutableMapCopyOfGenerator())
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS,
                CollectionFeature.KNOWN_ORDER,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .named("ImmutableMap.copyOf[Map]")
            .createTestSuite());

    suite.addTest(
        MapTestSuiteBuilder.using(new ImmutableMapCopyOfEntriesGenerator())
            .withFeatures(
                CollectionSize.ANY,
                MapFeature.REJECTS_DUPLICATES_AT_CREATION,
                CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS,
                CollectionFeature.KNOWN_ORDER,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .named("ImmutableMap.copyOf[Iterable<Entry>]")
            .createTestSuite());

    suite.addTest(
        MapTestSuiteBuilder.using(new ImmutableMapCopyOfEnumMapGenerator())
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS,
                CollectionFeature.KNOWN_ORDER,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .named("ImmutableMap.copyOf[EnumMap]")
            .createTestSuite());

    suite.addTest(
        MapTestSuiteBuilder.using(new ImmutableMapValuesAsSingletonSetGenerator())
            .withFeatures(
                CollectionSize.ANY,
                MapFeature.REJECTS_DUPLICATES_AT_CREATION,
                CollectionFeature.KNOWN_ORDER,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .named("ImmutableMap.asMultimap.asMap")
            .createTestSuite());

    suite.addTest(
        CollectionTestSuiteBuilder.using(new ImmutableMapUnhashableValuesGenerator())
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.KNOWN_ORDER,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .named("ImmutableMap.values, unhashable")
            .createTestSuite());

    suite.addTest(
        ListTestSuiteBuilder.using(new ImmutableMapKeyListGenerator())
            .named("ImmutableMap.keySet.asList")
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.SERIALIZABLE,
                CollectionFeature.REJECTS_DUPLICATES_AT_CREATION,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());

    suite.addTest(
        ListTestSuiteBuilder.using(new ImmutableMapEntryListGenerator())
            .named("ImmutableMap.entrySet.asList")
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.SERIALIZABLE,
                CollectionFeature.REJECTS_DUPLICATES_AT_CREATION,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());

    suite.addTest(
        ListTestSuiteBuilder.using(new ImmutableMapValueListGenerator())
            .named("ImmutableMap.values.asList")
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.SERIALIZABLE,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());

    return suite;
  }

  // Creation tests

  public void testEmptyBuilder() {
    ImmutableMap<String, Integer> map = new Builder<String, Integer>().buildOrThrow();
    assertEquals(Collections.<String, Integer>emptyMap(), map);
  }

  public void testSingletonBuilder() {
    ImmutableMap<String, Integer> map = new Builder<String, Integer>().put("one", 1).buildOrThrow();
    assertMapEquals(map, "one", 1);
  }

  public void testBuilder() {
    ImmutableMap<String, Integer> map =
        new Builder<String, Integer>()
            .put("one", 1)
            .put("two", 2)
            .put("three", 3)
            .put("four", 4)
            .put("five", 5)
            .buildOrThrow();
    assertMapEquals(map, "one", 1, "two", 2, "three", 3, "four", 4, "five", 5);
  }

  @GwtIncompatible
  public void testBuilderExactlySizedReusesArray() {
    ImmutableMap.Builder<Integer, Integer> builder = ImmutableMap.builderWithExpectedSize(10);
    Entry<Integer, Integer>[] builderArray = builder.entries;
    for (int i = 0; i < 10; i++) {
      builder.put(i, i);
    }
    Entry<Integer, Integer>[] builderArrayAfterPuts = builder.entries;
    RegularImmutableMap<Integer, Integer> map =
        (RegularImmutableMap<Integer, Integer>) builder.buildOrThrow();
    Entry<Integer, Integer>[] mapInternalArray = map.entries;
    assertSame(builderArray, builderArrayAfterPuts);
    assertSame(builderArray, mapInternalArray);
  }

  public void testBuilder_orderEntriesByValue() {
    ImmutableMap<String, Integer> map =
        new Builder<String, Integer>()
            .orderEntriesByValue(Ordering.natural())
            .put("three", 3)
            .put("one", 1)
            .put("five", 5)
            .put("four", 4)
            .put("two", 2)
            .buildOrThrow();
    assertMapEquals(map, "one", 1, "two", 2, "three", 3, "four", 4, "five", 5);
  }

  public void testBuilder_orderEntriesByValueAfterExactSizeBuild() {
    Builder<String, Integer> builder = new Builder<String, Integer>(2).put("four", 4).put("one", 1);
    ImmutableMap<String, Integer> keyOrdered = builder.buildOrThrow();
    ImmutableMap<String, Integer> valueOrdered =
        builder.orderEntriesByValue(Ordering.natural()).buildOrThrow();
    assertMapEquals(keyOrdered, "four", 4, "one", 1);
    assertMapEquals(valueOrdered, "one", 1, "four", 4);
  }

  public void testBuilder_orderEntriesByValue_usedTwiceFails() {
    ImmutableMap.Builder<String, Integer> builder =
        new Builder<String, Integer>().orderEntriesByValue(Ordering.natural());
    try {
      builder.orderEntriesByValue(Ordering.natural());
      fail("Expected IllegalStateException");
    } catch (IllegalStateException expected) {
    }
  }

  @GwtIncompatible // we haven't implemented this
  public void testBuilder_orderEntriesByValue_keepingLast() {
    ImmutableMap.Builder<String, Integer> builder =
        new Builder<String, Integer>()
            .orderEntriesByValue(Ordering.natural())
            .put("three", 3)
            .put("one", 1)
            .put("five", 5)
            .put("four", 3)
            .put("four", 5)
            .put("four", 4) // this should win because it's last
            .put("two", 2);
    assertMapEquals(
        builder.buildKeepingLast(), "one", 1, "two", 2, "three", 3, "four", 4, "five", 5);
    try {
      builder.buildOrThrow();
      fail("Expected exception from duplicate keys");
    } catch (IllegalArgumentException expected) {
    }
  }

  @GwtIncompatible // we haven't implemented this
  public void testBuilder_orderEntriesByValue_keepingLast_builderSizeFieldPreserved() {
    ImmutableMap.Builder<String, Integer> builder =
        new Builder<String, Integer>()
            .orderEntriesByValue(Ordering.natural())
            .put("one", 1)
            .put("one", 1);
    assertMapEquals(builder.buildKeepingLast(), "one", 1);
    try {
      builder.buildOrThrow();
      fail("Expected exception from duplicate keys");
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testBuilder_withImmutableEntry() {
    ImmutableMap<String, Integer> map =
        new Builder<String, Integer>().put(Maps.immutableEntry("one", 1)).buildOrThrow();
    assertMapEquals(map, "one", 1);
  }

  public void testBuilder_withImmutableEntryAndNullContents() {
    Builder<String, Integer> builder = new Builder<>();
    try {
      builder.put(Maps.immutableEntry("one", (Integer) null));
      fail();
    } catch (NullPointerException expected) {
    }
    try {
      builder.put(Maps.immutableEntry((String) null, 1));
      fail();
    } catch (NullPointerException expected) {
    }
  }

  private static class StringHolder {
    String string;
  }

  public void testBuilder_withMutableEntry() {
    ImmutableMap.Builder<String, Integer> builder = new Builder<>();
    final StringHolder holder = new StringHolder();
    holder.string = "one";
    Entry<String, Integer> entry =
        new AbstractMapEntry<String, Integer>() {
          @Override
          public String getKey() {
            return holder.string;
          }

          @Override
          public Integer getValue() {
            return 1;
          }
        };

    builder.put(entry);
    holder.string = "two";
    assertMapEquals(builder.buildOrThrow(), "one", 1);
  }

  public void testBuilderPutAllWithEmptyMap() {
    ImmutableMap<String, Integer> map =
        new Builder<String, Integer>()
            .putAll(Collections.<String, Integer>emptyMap())
            .buildOrThrow();
    assertEquals(Collections.<String, Integer>emptyMap(), map);
  }

  public void testBuilderPutAll() {
    Map<String, Integer> toPut = new LinkedHashMap<>();
    toPut.put("one", 1);
    toPut.put("two", 2);
    toPut.put("three", 3);
    Map<String, Integer> moreToPut = new LinkedHashMap<>();
    moreToPut.put("four", 4);
    moreToPut.put("five", 5);

    ImmutableMap<String, Integer> map =
        new Builder<String, Integer>().putAll(toPut).putAll(moreToPut).buildOrThrow();
    assertMapEquals(map, "one", 1, "two", 2, "three", 3, "four", 4, "five", 5);
  }

  public void testBuilderReuse() {
    Builder<String, Integer> builder = new Builder<>();
    ImmutableMap<String, Integer> mapOne = builder.put("one", 1).put("two", 2).buildOrThrow();
    ImmutableMap<String, Integer> mapTwo = builder.put("three", 3).put("four", 4).buildOrThrow();

    assertMapEquals(mapOne, "one", 1, "two", 2);
    assertMapEquals(mapTwo, "one", 1, "two", 2, "three", 3, "four", 4);
  }

  public void testBuilderPutNullKeyFailsAtomically() {
    Builder<String, Integer> builder = new Builder<>();
    try {
      builder.put(null, 1);
      fail();
    } catch (NullPointerException expected) {
    }
    builder.put("foo", 2);
    assertMapEquals(builder.buildOrThrow(), "foo", 2);
  }

  public void testBuilderPutImmutableEntryWithNullKeyFailsAtomically() {
    Builder<String, Integer> builder = new Builder<>();
    try {
      builder.put(Maps.immutableEntry((String) null, 1));
      fail();
    } catch (NullPointerException expected) {
    }
    builder.put("foo", 2);
    assertMapEquals(builder.buildOrThrow(), "foo", 2);
  }

  // for GWT compatibility
  static class SimpleEntry<K, V> extends AbstractMapEntry<K, V> {
    public K key;
    public V value;

    SimpleEntry(K key, V value) {
      this.key = key;
      this.value = value;
    }

    @Override
    public K getKey() {
      return key;
    }

    @Override
    public V getValue() {
      return value;
    }
  }

  public void testBuilderPutMutableEntryWithNullKeyFailsAtomically() {
    Builder<String, Integer> builder = new Builder<>();
    try {
      builder.put(new SimpleEntry<String, Integer>(null, 1));
      fail();
    } catch (NullPointerException expected) {
    }
    builder.put("foo", 2);
    assertMapEquals(builder.buildOrThrow(), "foo", 2);
  }

  public void testBuilderPutNullKey() {
    Builder<String, Integer> builder = new Builder<>();
    try {
      builder.put(null, 1);
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testBuilderPutNullValue() {
    Builder<String, Integer> builder = new Builder<>();
    try {
      builder.put("one", null);
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testBuilderPutNullKeyViaPutAll() {
    Builder<String, Integer> builder = new Builder<>();
    try {
      builder.putAll(Collections.<String, Integer>singletonMap(null, 1));
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testBuilderPutNullValueViaPutAll() {
    Builder<String, Integer> builder = new Builder<>();
    try {
      builder.putAll(Collections.<String, Integer>singletonMap("one", null));
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testPuttingTheSameKeyTwiceThrowsOnBuild() {
    Builder<String, Integer> builder =
        new Builder<String, Integer>()
            .put("one", 1)
            .put("one", 1); // throwing on this line might be better but it's too late to change

    try {
      builder.buildOrThrow();
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testBuildKeepingLast_allowsOverwrite() {
    Builder<Integer, String> builder =
        new Builder<Integer, String>()
            .put(1, "un")
            .put(2, "deux")
            .put(70, "soixante-dix")
            .put(70, "septante")
            .put(70, "seventy")
            .put(1, "one")
            .put(2, "two");
    ImmutableMap<Integer, String> map = builder.buildKeepingLast();
    assertMapEquals(map, 1, "one", 2, "two", 70, "seventy");
  }

  public void testBuildKeepingLast_smallTableSameHash() {
    String key1 = "QED";
    String key2 = "R&D";
    assertThat(key1.hashCode()).isEqualTo(key2.hashCode());
    ImmutableMap<String, Integer> map =
        ImmutableMap.<String, Integer>builder()
            .put(key1, 1)
            .put(key2, 2)
            .put(key1, 3)
            .put(key2, 4)
            .buildKeepingLast();
    assertMapEquals(map, key1, 3, key2, 4);
  }

  // The java7 branch has different code depending on whether the entry indexes fit in a byte,
  // short, or int. The small table in testBuildKeepingLast_allowsOverwrite will test the byte
  // case. This method tests the short case.
  public void testBuildKeepingLast_shortTable() {
    Builder<Integer, String> builder = ImmutableMap.builder();
    Map<Integer, String> expected = new LinkedHashMap<>();
    for (int i = 0; i < 1000; i++) {
      // Truncate to even key, so we have put(0, "0") then put(0, "1"). Half the entries are
      // duplicates.
      Integer key = i & ~1;
      String value = String.valueOf(i);
      builder.put(key, value);
      expected.put(key, value);
    }
    ImmutableMap<Integer, String> map = builder.buildKeepingLast();
    assertThat(map).hasSize(500);
    assertThat(map).containsExactlyEntriesIn(expected).inOrder();
  }

  // This method tests the int case.
  public void testBuildKeepingLast_bigTable() {
    Builder<Integer, String> builder = ImmutableMap.builder();
    Map<Integer, String> expected = new LinkedHashMap<>();
    for (int i = 0; i < 200_000; i++) {
      // Truncate to even key, so we have put(0, "0") then put(0, "1"). Half the entries are
      // duplicates.
      Integer key = i & ~1;
      String value = String.valueOf(i);
      builder.put(key, value);
      expected.put(key, value);
    }
    ImmutableMap<Integer, String> map = builder.buildKeepingLast();
    assertThat(map).hasSize(100_000);
    assertThat(map).containsExactlyEntriesIn(expected).inOrder();
  }

  private static class ClassWithTerribleHashCode implements Comparable<ClassWithTerribleHashCode> {
    private final int value;

    ClassWithTerribleHashCode(int value) {
      this.value = value;
    }

    @Override
    public int compareTo(ClassWithTerribleHashCode that) {
      return Integer.compare(this.value, that.value);
    }

    @Override
    public boolean equals(@Nullable Object x) {
      return x instanceof ClassWithTerribleHashCode
          && ((ClassWithTerribleHashCode) x).value == value;
    }

    @Override
    public int hashCode() {
      return 23;
    }

    @Override
    public String toString() {
      return "ClassWithTerribleHashCode(" + value + ")";
    }
  }

  @GwtIncompatible
  public void testBuildKeepingLast_collisions() {
    Map<ClassWithTerribleHashCode, Integer> expected = new LinkedHashMap<>();
    Builder<ClassWithTerribleHashCode, Integer> builder = new Builder<>();
    int size = RegularImmutableMap.MAX_HASH_BUCKET_LENGTH + 10;
    for (int i = 0; i < size; i++) {
      ClassWithTerribleHashCode key = new ClassWithTerribleHashCode(i);
      builder.put(key, i);
      builder.put(key, -i);
      expected.put(key, -i);
    }
    ImmutableMap<ClassWithTerribleHashCode, Integer> map = builder.buildKeepingLast();
    assertThat(map).containsExactlyEntriesIn(expected).inOrder();
    assertThat(map).isInstanceOf(JdkBackedImmutableMap.class);
  }

  @GwtIncompatible // Pattern, Matcher
  public void testBuilder_keepingLast_thenOrThrow() {
    ImmutableMap.Builder<String, Integer> builder =
        new Builder<String, Integer>()
            .put("three", 3)
            .put("one", 1)
            .put("five", 5)
            .put("four", 3)
            .put("four", 5)
            .put("four", 4) // this should win because it's last
            .put("two", 2);
    assertMapEquals(
        builder.buildKeepingLast(), "three", 3, "one", 1, "five", 5, "four", 4, "two", 2);
    try {
      builder.buildOrThrow();
      fail("Expected exception from duplicate keys");
    } catch (IllegalArgumentException expected) {
      // We don't really care which values the exception message contains, but they should be
      // different from each other. If buildKeepingLast() collapsed duplicates, that might end up
      // not being true.
      Pattern pattern = Pattern.compile("Multiple entries with same key: four=(.*) and four=(.*)");
      assertThat(expected).hasMessageThat().matches(pattern);
      Matcher matcher = pattern.matcher(expected.getMessage());
      assertThat(matcher.matches()).isTrue();
      assertThat(matcher.group(1)).isNotEqualTo(matcher.group(2));
    }
  }

  public void testOf() {
    assertMapEquals(ImmutableMap.of("one", 1), "one", 1);
    assertMapEquals(ImmutableMap.of("one", 1, "two", 2), "one", 1, "two", 2);
    assertMapEquals(
        ImmutableMap.of("one", 1, "two", 2, "three", 3), "one", 1, "two", 2, "three", 3);
    assertMapEquals(
        ImmutableMap.of("one", 1, "two", 2, "three", 3, "four", 4),
        "one",
        1,
        "two",
        2,
        "three",
        3,
        "four",
        4);
    assertMapEquals(
        ImmutableMap.of("one", 1, "two", 2, "three", 3, "four", 4, "five", 5),
        "one",
        1,
        "two",
        2,
        "three",
        3,
        "four",
        4,
        "five",
        5);
    assertMapEquals(
        ImmutableMap.of(
            "one", 1,
            "two", 2,
            "three", 3,
            "four", 4,
            "five", 5,
            "six", 6),
        "one",
        1,
        "two",
        2,
        "three",
        3,
        "four",
        4,
        "five",
        5,
        "six",
        6);
    assertMapEquals(
        ImmutableMap.of(
            "one", 1,
            "two", 2,
            "three", 3,
            "four", 4,
            "five", 5,
            "six", 6,
            "seven", 7),
        "one",
        1,
        "two",
        2,
        "three",
        3,
        "four",
        4,
        "five",
        5,
        "six",
        6,
        "seven",
        7);
    assertMapEquals(
        ImmutableMap.of(
            "one", 1,
            "two", 2,
            "three", 3,
            "four", 4,
            "five", 5,
            "six", 6,
            "seven", 7,
            "eight", 8),
        "one",
        1,
        "two",
        2,
        "three",
        3,
        "four",
        4,
        "five",
        5,
        "six",
        6,
        "seven",
        7,
        "eight",
        8);
    assertMapEquals(
        ImmutableMap.of(
            "one", 1,
            "two", 2,
            "three", 3,
            "four", 4,
            "five", 5,
            "six", 6,
            "seven", 7,
            "eight", 8,
            "nine", 9),
        "one",
        1,
        "two",
        2,
        "three",
        3,
        "four",
        4,
        "five",
        5,
        "six",
        6,
        "seven",
        7,
        "eight",
        8,
        "nine",
        9);
    assertMapEquals(
        ImmutableMap.of(
            "one", 1,
            "two", 2,
            "three", 3,
            "four", 4,
            "five", 5,
            "six", 6,
            "seven", 7,
            "eight", 8,
            "nine", 9,
            "ten", 10),
        "one",
        1,
        "two",
        2,
        "three",
        3,
        "four",
        4,
        "five",
        5,
        "six",
        6,
        "seven",
        7,
        "eight",
        8,
        "nine",
        9,
        "ten",
        10);
  }

  public void testOfNullKey() {
    try {
      ImmutableMap.of(null, 1);
      fail();
    } catch (NullPointerException expected) {
    }

    try {
      ImmutableMap.of("one", 1, null, 2);
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testOfNullValue() {
    try {
      ImmutableMap.of("one", null);
      fail();
    } catch (NullPointerException expected) {
    }

    try {
      ImmutableMap.of("one", 1, "two", null);
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testOfWithDuplicateKey() {
    try {
      ImmutableMap.of("one", 1, "one", 1);
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testCopyOfEmptyMap() {
    ImmutableMap<String, Integer> copy =
        ImmutableMap.copyOf(Collections.<String, Integer>emptyMap());
    assertEquals(Collections.<String, Integer>emptyMap(), copy);
    assertSame(copy, ImmutableMap.copyOf(copy));
  }

  public void testCopyOfSingletonMap() {
    ImmutableMap<String, Integer> copy = ImmutableMap.copyOf(Collections.singletonMap("one", 1));
    assertMapEquals(copy, "one", 1);
    assertSame(copy, ImmutableMap.copyOf(copy));
  }

  public void testCopyOf() {
    Map<String, Integer> original = new LinkedHashMap<>();
    original.put("one", 1);
    original.put("two", 2);
    original.put("three", 3);

    ImmutableMap<String, Integer> copy = ImmutableMap.copyOf(original);
    assertMapEquals(copy, "one", 1, "two", 2, "three", 3);
    assertSame(copy, ImmutableMap.copyOf(copy));
  }

  public void testToImmutableMap() {
    Collector<Entry<String, Integer>, ?, ImmutableMap<String, Integer>> collector =
        ImmutableMap.toImmutableMap(Entry::getKey, Entry::getValue);
    Equivalence<ImmutableMap<String, Integer>> equivalence =
        Equivalence.equals().<Entry<String, Integer>>pairwise().onResultOf(ImmutableMap::entrySet);
    CollectorTester.of(collector, equivalence)
        .expectCollects(
            ImmutableMap.of("one", 1, "two", 2, "three", 3),
            mapEntry("one", 1),
            mapEntry("two", 2),
            mapEntry("three", 3));
  }

  public void testToImmutableMap_exceptionOnDuplicateKey() {
    Collector<Entry<String, Integer>, ?, ImmutableMap<String, Integer>> collector =
        ImmutableMap.toImmutableMap(Entry::getKey, Entry::getValue);
    try {
      Stream.of(mapEntry("one", 1), mapEntry("one", 11)).collect(collector);
      fail("Expected IllegalArgumentException");
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testToImmutableMapMerging() {
    Collector<Entry<String, Integer>, ?, ImmutableMap<String, Integer>> collector =
        ImmutableMap.toImmutableMap(Entry::getKey, Entry::getValue, Integer::sum);
    Equivalence<ImmutableMap<String, Integer>> equivalence =
        Equivalence.equals().<Entry<String, Integer>>pairwise().onResultOf(ImmutableMap::entrySet);
    CollectorTester.of(collector, equivalence)
        .expectCollects(
            ImmutableMap.of("one", 1, "two", 4, "three", 3),
            mapEntry("one", 1),
            mapEntry("two", 2),
            mapEntry("three", 3),
            mapEntry("two", 2));
  }

  // Non-creation tests

  public void testNullGet() {
    ImmutableMap<String, Integer> map = ImmutableMap.of("one", 1);
    assertNull(map.get(null));
  }

  public void testAsMultimap() {
    ImmutableMap<String, Integer> map =
        ImmutableMap.of("one", 1, "won", 1, "two", 2, "too", 2, "three", 3);
    ImmutableSetMultimap<String, Integer> expected =
        ImmutableSetMultimap.of("one", 1, "won", 1, "two", 2, "too", 2, "three", 3);
    assertEquals(expected, map.asMultimap());
  }

  public void testAsMultimapWhenEmpty() {
    ImmutableMap<String, Integer> map = ImmutableMap.of();
    ImmutableSetMultimap<String, Integer> expected = ImmutableSetMultimap.of();
    assertEquals(expected, map.asMultimap());
  }

  public void testAsMultimapCaches() {
    ImmutableMap<String, Integer> map = ImmutableMap.of("one", 1);
    ImmutableSetMultimap<String, Integer> multimap1 = map.asMultimap();
    ImmutableSetMultimap<String, Integer> multimap2 = map.asMultimap();
    assertEquals(1, multimap1.asMap().size());
    assertSame(multimap1, multimap2);
  }

  @GwtIncompatible // NullPointerTester
  @AndroidIncompatible // see ImmutableTableTest.testNullPointerInstance
  public void testNullPointers() {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicStaticMethods(ImmutableMap.class);
    tester.testAllPublicInstanceMethods(new ImmutableMap.Builder<Object, Object>());
    tester.testAllPublicInstanceMethods(ImmutableMap.of());
    tester.testAllPublicInstanceMethods(ImmutableMap.of("one", 1));
    tester.testAllPublicInstanceMethods(ImmutableMap.of("one", 1, "two", 2, "three", 3));
  }

  private static <K, V> void assertMapEquals(Map<K, V> map, Object... alternatingKeysAndValues) {
    Map<Object, Object> expected = new LinkedHashMap<>();
    for (int i = 0; i < alternatingKeysAndValues.length; i += 2) {
      expected.put(alternatingKeysAndValues[i], alternatingKeysAndValues[i + 1]);
    }
    assertThat(map).containsExactlyEntriesIn(expected).inOrder();
  }

  private static class IntHolder implements Serializable {
    public int value;

    public IntHolder(int value) {
      this.value = value;
    }

    @Override
    public boolean equals(@Nullable Object o) {
      return (o instanceof IntHolder) && ((IntHolder) o).value == value;
    }

    @Override
    public int hashCode() {
      return value;
    }

    private static final long serialVersionUID = 5;
  }

  public void testMutableValues() {
    IntHolder holderA = new IntHolder(1);
    IntHolder holderB = new IntHolder(2);
    Map<String, IntHolder> map = ImmutableMap.of("a", holderA, "b", holderB);
    holderA.value = 3;
    assertTrue(map.entrySet().contains(Maps.immutableEntry("a", new IntHolder(3))));
    Map<String, Integer> intMap = ImmutableMap.of("a", 3, "b", 2);
    assertEquals(intMap.hashCode(), map.entrySet().hashCode());
    assertEquals(intMap.hashCode(), map.hashCode());
  }

  public void testCopyOfEnumMap() {
    EnumMap<AnEnum, String> map = new EnumMap<>(AnEnum.class);
    map.put(AnEnum.B, "foo");
    map.put(AnEnum.C, "bar");
    assertTrue(ImmutableMap.copyOf(map) instanceof ImmutableEnumMap);
  }

  @GwtIncompatible // SerializableTester
  public void testViewSerialization() {
    Map<String, Integer> map = ImmutableMap.of("one", 1, "two", 2, "three", 3);
    LenientSerializableTester.reserializeAndAssertLenient(map.entrySet());
    LenientSerializableTester.reserializeAndAssertLenient(map.keySet());

    Collection<Integer> reserializedValues = reserialize(map.values());
    assertEquals(Lists.newArrayList(map.values()), Lists.newArrayList(reserializedValues));
    assertTrue(reserializedValues instanceof ImmutableCollection);
  }

  @GwtIncompatible // SerializableTester
  public void testKeySetIsSerializable_regularImmutableMap() {
    class NonSerializableClass {}

    Map<String, NonSerializableClass> map =
        RegularImmutableMap.fromEntries(ImmutableMap.entryOf("one", new NonSerializableClass()));
    Set<String> set = map.keySet();

    LenientSerializableTester.reserializeAndAssertLenient(set);
  }

  @GwtIncompatible // SerializableTester
  public void testKeySetIsSerializable_jdkBackedImmutableMap() {
    class NonSerializableClass {}

    Entry<String, NonSerializableClass>[] entries =
        arrayOf(ImmutableMap.entryOf("one", new NonSerializableClass()));

    ImmutableMap<String, NonSerializableClass> map =
        JdkBackedImmutableMap.create(1, entries, /* throwIfDuplicateKeys= */ true);
    Set<String> set = map.keySet();

    LenientSerializableTester.reserializeAndAssertLenient(set);
  }

  @GwtIncompatible // SerializableTester
  public void testValuesCollectionIsSerializable_regularImmutableMap() {
    class NonSerializableClass {}

    Map<NonSerializableClass, String> map =
        RegularImmutableMap.fromEntries(ImmutableMap.entryOf(new NonSerializableClass(), "value"));
    Collection<String> collection = map.values();

    LenientSerializableTester.reserializeAndAssertElementsEqual(collection);
  }

  @GwtIncompatible // SerializableTester
  public void testValuesCollectionIsSerializable_jdkBackedImmutableMap() {
    class NonSerializableClass {}

    Entry<NonSerializableClass, String>[] entries =
        arrayOf(ImmutableMap.entryOf(new NonSerializableClass(), "value"));

    ImmutableMap<NonSerializableClass, String> map =
        JdkBackedImmutableMap.create(1, entries, /* throwIfDuplicateKeys= */ true);
    Collection<String> collection = map.values();

    LenientSerializableTester.reserializeAndAssertElementsEqual(collection);
  }

  // TODO: Re-enable this test after moving to new serialization format in ImmutableMap.
  @GwtIncompatible // SerializableTester
  @SuppressWarnings("unchecked")
  public void ignore_testSerializationNoDuplication_regularImmutableMap() throws Exception {
    // Tests that serializing a map, its keySet, and values only writes the underlying data once.

    Entry<Integer, Integer>[] entries = (Entry<Integer, Integer>[]) new Entry<?, ?>[1000];
    for (int i = 0; i < 1000; i++) {
      entries[i] = ImmutableMap.entryOf(i, i);
    }

    ImmutableMap<Integer, Integer> map = RegularImmutableMap.fromEntries(entries);
    Set<Integer> keySet = map.keySet();
    Collection<Integer> values = map.values();

    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    ObjectOutputStream oos = new ObjectOutputStream(bytes);
    oos.writeObject(map);
    oos.flush();

    int mapSize = bytes.size();
    oos.writeObject(keySet);
    oos.writeObject(values);
    oos.close();

    int finalSize = bytes.size();

    assertThat(finalSize - mapSize).isLessThan(100);
  }

  // TODO: Re-enable this test after moving to new serialization format in ImmutableMap.
  @GwtIncompatible // SerializableTester
  @SuppressWarnings("unchecked")
  public void ignore_testSerializationNoDuplication_jdkBackedImmutableMap() throws Exception {
    // Tests that serializing a map, its keySet, and values only writes
    // the underlying data once.

    Entry<Integer, Integer>[] entries = (Entry<Integer, Integer>[]) new Entry<?, ?>[1000];
    for (int i = 0; i < 1000; i++) {
      entries[i] = ImmutableMap.entryOf(i, i);
    }

    ImmutableMap<Integer, Integer> map =
        JdkBackedImmutableMap.create(entries.length, entries, /* throwIfDuplicateKeys= */ true);
    Set<Integer> keySet = map.keySet();
    Collection<Integer> values = map.values();

    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    ObjectOutputStream oos = new ObjectOutputStream(bytes);
    oos.writeObject(map);
    oos.flush();

    int mapSize = bytes.size();
    oos.writeObject(keySet);
    oos.writeObject(values);
    oos.close();

    int finalSize = bytes.size();

    assertThat(finalSize - mapSize).isLessThan(100);
  }

  private static <T> T[] arrayOf(T... objs) {
    return objs;
  }

  @GwtIncompatible("assumptions about splitting")
  public void testKeySetSplittable() {
    ImmutableMap<Integer, Integer> map =
        ImmutableMap.<Integer, Integer>builder()
            .put(1, 1)
            .put(2, 2)
            .put(3, 3)
            .put(4, 4)
            .put(5, 5)
            .put(6, 6)
            .buildOrThrow();
    assertNotNull(map.keySet().spliterator().trySplit());
  }

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(
            ImmutableMap.of(),
            ImmutableMap.builder().buildOrThrow(),
            ImmutableMap.ofEntries(),
            map())
        .addEqualityGroup(
            ImmutableMap.of(1, 1),
            ImmutableMap.builder().put(1, 1).buildOrThrow(),
            ImmutableMap.ofEntries(entry(1, 1)),
            map(1, 1))
        .addEqualityGroup(
            ImmutableMap.of(1, 1, 2, 2),
            ImmutableMap.builder().put(1, 1).put(2, 2).buildOrThrow(),
            ImmutableMap.ofEntries(entry(1, 1), entry(2, 2)),
            map(1, 1, 2, 2))
        .addEqualityGroup(
            ImmutableMap.of(1, 1, 2, 2, 3, 3),
            ImmutableMap.builder().put(1, 1).put(2, 2).put(3, 3).buildOrThrow(),
            ImmutableMap.ofEntries(entry(1, 1), entry(2, 2), entry(3, 3)),
            map(1, 1, 2, 2, 3, 3))
        .addEqualityGroup(
            ImmutableMap.of(1, 4, 2, 2, 3, 3),
            ImmutableMap.builder().put(1, 4).put(2, 2).put(3, 3).buildOrThrow(),
            ImmutableMap.ofEntries(entry(1, 4), entry(2, 2), entry(3, 3)),
            map(1, 4, 2, 2, 3, 3))
        .addEqualityGroup(
            ImmutableMap.of(1, 1, 2, 4, 3, 3),
            ImmutableMap.builder().put(1, 1).put(2, 4).put(3, 3).buildOrThrow(),
            ImmutableMap.ofEntries(entry(1, 1), entry(2, 4), entry(3, 3)),
            map(1, 1, 2, 4, 3, 3))
        .addEqualityGroup(
            ImmutableMap.of(1, 1, 2, 2, 3, 4),
            ImmutableMap.builder().put(1, 1).put(2, 2).put(3, 4).buildOrThrow(),
            ImmutableMap.ofEntries(entry(1, 1), entry(2, 2), entry(3, 4)),
            map(1, 1, 2, 2, 3, 4))
        .addEqualityGroup(
            ImmutableMap.of(1, 2, 2, 3, 3, 1),
            ImmutableMap.builder().put(1, 2).put(2, 3).put(3, 1).buildOrThrow(),
            ImmutableMap.ofEntries(entry(1, 2), entry(2, 3), entry(3, 1)),
            map(1, 2, 2, 3, 3, 1))
        .addEqualityGroup(
            ImmutableMap.of(1, 1, 2, 2, 3, 3, 4, 4),
            ImmutableMap.builder().put(1, 1).put(2, 2).put(3, 3).put(4, 4).buildOrThrow(),
            ImmutableMap.ofEntries(entry(1, 1), entry(2, 2), entry(3, 3), entry(4, 4)),
            map(1, 1, 2, 2, 3, 3, 4, 4))
        .addEqualityGroup(
            ImmutableMap.of(1, 1, 2, 2, 3, 3, 4, 4, 5, 5),
            ImmutableMap.builder().put(1, 1).put(2, 2).put(3, 3).put(4, 4).put(5, 5).buildOrThrow(),
            ImmutableMap.ofEntries(entry(1, 1), entry(2, 2), entry(3, 3), entry(4, 4), entry(5, 5)),
            map(1, 1, 2, 2, 3, 3, 4, 4, 5, 5))
        .testEquals();
  }

  public void testOfEntriesNull() {
    Entry<Integer, Integer> nullKey = entry(null, 23);
    try {
      ImmutableMap.ofEntries(nullKey);
      fail();
    } catch (NullPointerException expected) {
    }
    Entry<Integer, Integer> nullValue = entry(23, null);
    try {
      ImmutableMap.ofEntries(nullValue);
      fail();
    } catch (NullPointerException expected) {
    }
  }

  private static <T> Map<T, T> map(T... keysAndValues) {
    assertThat(keysAndValues.length % 2).isEqualTo(0);
    LinkedHashMap<T, T> map = new LinkedHashMap<>();
    for (int i = 0; i < keysAndValues.length; i += 2) {
      T key = keysAndValues[i];
      T value = keysAndValues[i + 1];
      T old = map.put(key, value);
      assertWithMessage("Key %s set to %s and %s", key, value, old).that(old).isNull();
    }
    return map;
  }

  private static <T> Entry<T, T> entry(T key, T value) {
    return new AbstractMap.SimpleImmutableEntry<>(key, value);
  }

  public void testCopyOfMutableEntryList() {
    List<Entry<String, String>> entryList =
        Arrays.asList(
            new AbstractMap.SimpleEntry<>("a", "1"), new AbstractMap.SimpleEntry<>("b", "2"));
    ImmutableMap<String, String> map = ImmutableMap.copyOf(entryList);
    assertThat(map).containsExactly("a", "1", "b", "2").inOrder();
    entryList.get(0).setValue("3");
    assertThat(map).containsExactly("a", "1", "b", "2").inOrder();
  }

  public void testBuilderPutAllEntryList() {
    List<Entry<String, String>> entryList =
        Arrays.asList(
            new AbstractMap.SimpleEntry<>("a", "1"), new AbstractMap.SimpleEntry<>("b", "2"));
    ImmutableMap<String, String> map =
        ImmutableMap.<String, String>builder().putAll(entryList).buildOrThrow();
    assertThat(map).containsExactly("a", "1", "b", "2").inOrder();
    entryList.get(0).setValue("3");
    assertThat(map).containsExactly("a", "1", "b", "2").inOrder();
  }

  public void testBuilderPutAllEntryListJdkBacked() {
    List<Entry<String, String>> entryList =
        Arrays.asList(
            new AbstractMap.SimpleEntry<>("a", "1"), new AbstractMap.SimpleEntry<>("b", "2"));
    ImmutableMap<String, String> map =
        ImmutableMap.<String, String>builder().putAll(entryList).buildJdkBacked();
    assertThat(map).containsExactly("a", "1", "b", "2").inOrder();
    entryList.get(0).setValue("3");
    assertThat(map).containsExactly("a", "1", "b", "2").inOrder();
  }
}