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/*
* Copyright (C) 2016 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.truth.Truth.assertThat;
import static java.util.Arrays.asList;
import static java.util.Comparator.comparing;
import static java.util.Comparator.naturalOrder;
import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.Helpers;
import com.google.common.testing.EqualsTester;
import java.util.Collections;
import java.util.Comparator;
import java.util.Optional;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* Tests for {@code Comparators}.
*
* @author Louis Wasserman
*/
@GwtCompatible
public class ComparatorsTest extends TestCase {
@SuppressWarnings("unchecked") // dang varargs
public void testLexicographical() {
Comparator<String> comparator = Ordering.natural();
Comparator<Iterable<String>> lexy = Comparators.lexicographical(comparator);
ImmutableList<String> empty = ImmutableList.of();
ImmutableList<String> a = ImmutableList.of("a");
ImmutableList<String> aa = ImmutableList.of("a", "a");
ImmutableList<String> ab = ImmutableList.of("a", "b");
ImmutableList<String> b = ImmutableList.of("b");
Helpers.testComparator(lexy, empty, a, aa, ab, b);
new EqualsTester()
.addEqualityGroup(lexy, Comparators.lexicographical(comparator))
.addEqualityGroup(Comparators.lexicographical(String.CASE_INSENSITIVE_ORDER))
.addEqualityGroup(Ordering.natural())
.testEquals();
}
public void testIsInOrder() {
assertFalse(Comparators.isInOrder(asList(5, 3, 0, 9), Ordering.natural()));
assertFalse(Comparators.isInOrder(asList(0, 5, 3, 9), Ordering.natural()));
assertTrue(Comparators.isInOrder(asList(0, 3, 5, 9), Ordering.natural()));
assertTrue(Comparators.isInOrder(asList(0, 0, 3, 3), Ordering.natural()));
assertTrue(Comparators.isInOrder(asList(0, 3), Ordering.natural()));
assertTrue(Comparators.isInOrder(Collections.singleton(1), Ordering.natural()));
assertTrue(Comparators.isInOrder(Collections.<Integer>emptyList(), Ordering.natural()));
}
public void testIsInStrictOrder() {
assertFalse(Comparators.isInStrictOrder(asList(5, 3, 0, 9), Ordering.natural()));
assertFalse(Comparators.isInStrictOrder(asList(0, 5, 3, 9), Ordering.natural()));
assertTrue(Comparators.isInStrictOrder(asList(0, 3, 5, 9), Ordering.natural()));
assertFalse(Comparators.isInStrictOrder(asList(0, 0, 3, 3), Ordering.natural()));
assertTrue(Comparators.isInStrictOrder(asList(0, 3), Ordering.natural()));
assertTrue(Comparators.isInStrictOrder(Collections.singleton(1), Ordering.natural()));
assertTrue(Comparators.isInStrictOrder(Collections.<Integer>emptyList(), Ordering.natural()));
}
public void testEmptiesFirst() {
Optional<String> empty = Optional.empty();
Optional<String> abc = Optional.of("abc");
Optional<String> z = Optional.of("z");
Comparator<Optional<String>> comparator = Comparators.emptiesFirst(comparing(String::length));
Helpers.testComparator(comparator, empty, z, abc);
// Just demonstrate that no explicit type parameter is required
comparator = Comparators.emptiesFirst(naturalOrder());
}
public void testEmptiesLast() {
Optional<String> empty = Optional.empty();
Optional<String> abc = Optional.of("abc");
Optional<String> z = Optional.of("z");
Comparator<Optional<String>> comparator = Comparators.emptiesLast(comparing(String::length));
Helpers.testComparator(comparator, z, abc, empty);
// Just demonstrate that no explicit type parameter is required
comparator = Comparators.emptiesLast(naturalOrder());
}
public void testMinMaxNatural() {
assertThat(Comparators.min(1, 2)).isEqualTo(1);
assertThat(Comparators.min(2, 1)).isEqualTo(1);
assertThat(Comparators.max(1, 2)).isEqualTo(2);
assertThat(Comparators.max(2, 1)).isEqualTo(2);
}
public void testMinMaxNatural_equalInstances() {
Foo a = new Foo(1);
Foo b = new Foo(1);
assertThat(Comparators.min(a, b)).isSameInstanceAs(a);
assertThat(Comparators.max(a, b)).isSameInstanceAs(a);
}
public void testMinMaxComparator() {
Comparator<Integer> natural = Ordering.natural();
Comparator<Integer> reverse = Collections.reverseOrder(natural);
assertThat(Comparators.min(1, 2, reverse)).isEqualTo(2);
assertThat(Comparators.min(2, 1, reverse)).isEqualTo(2);
assertThat(Comparators.max(1, 2, reverse)).isEqualTo(1);
assertThat(Comparators.max(2, 1, reverse)).isEqualTo(1);
}
public void testMinMaxComparator_equalInstances() {
Comparator<Foo> natural = Ordering.natural();
Comparator<Foo> reverse = Collections.reverseOrder(natural);
Foo a = new Foo(1);
Foo b = new Foo(1);
assertThat(Comparators.min(a, b, reverse)).isSameInstanceAs(a);
assertThat(Comparators.max(a, b, reverse)).isSameInstanceAs(a);
}
private static class Foo implements Comparable<Foo> {
final Integer value;
Foo(int value) {
this.value = value;
}
@Override
public int hashCode() {
return value.hashCode();
}
@Override
public boolean equals(@Nullable Object o) {
return (o instanceof Foo) && ((Foo) o).value.equals(value);
}
@Override
public int compareTo(Foo other) {
return value.compareTo(other.value);
}
}
}
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