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Guava testlib is a set of java classes used for more convenient
unit testing - particularly to assist the tests for Guava itself.
/*
* Copyright (C) 2015 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.testing;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.testing.Helpers.assertEqualIgnoringOrder;
import static com.google.common.collect.testing.Helpers.assertEqualInOrder;
import static com.google.common.collect.testing.Platform.format;
import static java.util.Arrays.asList;
import static java.util.Collections.unmodifiableSet;
import static junit.framework.Assert.assertEquals;
import static junit.framework.Assert.assertFalse;
import static junit.framework.Assert.assertTrue;
import static junit.framework.Assert.fail;
import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Ordering;
import com.google.common.primitives.Ints;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import java.util.Spliterator;
import java.util.Spliterator.OfPrimitive;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Supplier;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* Tester for {@code Spliterator} implementations.
*
* @since 21.0
*/
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class SpliteratorTester {
/** Return type from "contains the following elements" assertions. */
public interface Ordered {
/**
* Attests that the expected values must not just be present but must be present in the order
* they were given.
*/
void inOrder();
}
private abstract static class GeneralSpliterator {
final Spliterator spliterator;
GeneralSpliterator(Spliterator spliterator) {
this.spliterator = checkNotNull(spliterator);
}
abstract void forEachRemaining(Consumer action);
abstract boolean tryAdvance(Consumer action);
abstract @Nullable GeneralSpliterator trySplit();
final int characteristics() {
return spliterator.characteristics();
}
final long estimateSize() {
return spliterator.estimateSize();
}
final Comparator getComparator() {
return spliterator.getComparator();
}
final long getExactSizeIfKnown() {
return spliterator.getExactSizeIfKnown();
}
final boolean hasCharacteristics(int characteristics) {
return spliterator.hasCharacteristics(characteristics);
}
}
private static final class GeneralSpliteratorOfObject
extends GeneralSpliterator {
GeneralSpliteratorOfObject(Spliterator spliterator) {
super(spliterator);
}
@Override
void forEachRemaining(Consumer action) {
spliterator.forEachRemaining(action);
}
@Override
boolean tryAdvance(Consumer action) {
return spliterator.tryAdvance(action);
}
@Override
@Nullable GeneralSpliterator trySplit() {
Spliterator split = spliterator.trySplit();
return split == null ? null : new GeneralSpliteratorOfObject<>(split);
}
}
private static final class GeneralSpliteratorOfPrimitive<
E extends @Nullable Object, C, S extends Spliterator.OfPrimitive>
extends GeneralSpliterator {
final OfPrimitive spliteratorOfPrimitive;
final Function, C> consumerizer;
GeneralSpliteratorOfPrimitive(
Spliterator.OfPrimitive spliterator,
Function, C> consumerizer) {
super(spliterator);
this.spliteratorOfPrimitive = spliterator;
this.consumerizer = consumerizer;
}
@Override
void forEachRemaining(Consumer action) {
spliteratorOfPrimitive.forEachRemaining(consumerizer.apply(action));
}
@Override
boolean tryAdvance(Consumer action) {
return spliteratorOfPrimitive.tryAdvance(consumerizer.apply(action));
}
@Override
@Nullable GeneralSpliterator trySplit() {
Spliterator.OfPrimitive split = spliteratorOfPrimitive.trySplit();
return split == null ? null : new GeneralSpliteratorOfPrimitive<>(split, consumerizer);
}
}
/**
* Different ways of decomposing a Spliterator, all of which must produce the same elements (up to
* ordering, if Spliterator.ORDERED is not present).
*/
enum SpliteratorDecompositionStrategy {
NO_SPLIT_FOR_EACH_REMAINING {
@Override
void forEach(
GeneralSpliterator spliterator, Consumer consumer) {
spliterator.forEachRemaining(consumer);
}
},
NO_SPLIT_TRY_ADVANCE {
@Override
void forEach(
GeneralSpliterator spliterator, Consumer consumer) {
while (spliterator.tryAdvance(consumer)) {
// do nothing
}
}
},
MAXIMUM_SPLIT {
@Override
void forEach(
GeneralSpliterator spliterator, Consumer consumer) {
for (GeneralSpliterator prefix = trySplitTestingSize(spliterator);
prefix != null;
prefix = trySplitTestingSize(spliterator)) {
forEach(prefix, consumer);
}
long size = spliterator.getExactSizeIfKnown();
long[] counter = {0};
spliterator.forEachRemaining(
e -> {
consumer.accept(e);
counter[0]++;
});
if (size >= 0) {
assertEquals(size, counter[0]);
}
}
},
ALTERNATE_ADVANCE_AND_SPLIT {
@Override
void forEach(
GeneralSpliterator spliterator, Consumer consumer) {
while (spliterator.tryAdvance(consumer)) {
GeneralSpliterator prefix = trySplitTestingSize(spliterator);
if (prefix != null) {
forEach(prefix, consumer);
}
}
}
};
abstract void forEach(
GeneralSpliterator spliterator, Consumer consumer);
static final Set ALL_STRATEGIES =
unmodifiableSet(new LinkedHashSet<>(asList(values())));
}
private static @Nullable GeneralSpliterator trySplitTestingSize(
GeneralSpliterator spliterator) {
boolean subsized = spliterator.hasCharacteristics(Spliterator.SUBSIZED);
long originalSize = spliterator.estimateSize();
GeneralSpliterator trySplit = spliterator.trySplit();
if (spliterator.estimateSize() > originalSize) {
fail(
format(
"estimated size of spliterator after trySplit (%s) is larger than original size (%s)",
spliterator.estimateSize(), originalSize));
}
if (trySplit != null) {
if (trySplit.estimateSize() > originalSize) {
fail(
format(
"estimated size of trySplit result (%s) is larger than original size (%s)",
trySplit.estimateSize(), originalSize));
}
}
if (subsized) {
if (trySplit != null) {
assertEquals(
"sum of estimated sizes of trySplit and original spliterator after trySplit",
originalSize,
trySplit.estimateSize() + spliterator.estimateSize());
} else {
assertEquals(
"estimated size of spliterator after failed trySplit",
originalSize,
spliterator.estimateSize());
}
}
return trySplit;
}
public static SpliteratorTester of(
Supplier> spliteratorSupplier) {
return new SpliteratorTester<>(
ImmutableSet.of(() -> new GeneralSpliteratorOfObject<>(spliteratorSupplier.get())));
}
/**
* @since 28.1
*/
public static SpliteratorTester ofInt(Supplier spliteratorSupplier) {
return new SpliteratorTester<>(
ImmutableSet.of(
() -> new GeneralSpliteratorOfObject<>(spliteratorSupplier.get()),
() -> new GeneralSpliteratorOfPrimitive<>(spliteratorSupplier.get(), c -> c::accept)));
}
/**
* @since 28.1
*/
public static SpliteratorTester ofLong(Supplier spliteratorSupplier) {
return new SpliteratorTester<>(
ImmutableSet.of(
() -> new GeneralSpliteratorOfObject<>(spliteratorSupplier.get()),
() -> new GeneralSpliteratorOfPrimitive<>(spliteratorSupplier.get(), c -> c::accept)));
}
/**
* @since 28.1
*/
public static SpliteratorTester ofDouble(
Supplier spliteratorSupplier) {
return new SpliteratorTester<>(
ImmutableSet.of(
() -> new GeneralSpliteratorOfObject<>(spliteratorSupplier.get()),
() -> new GeneralSpliteratorOfPrimitive<>(spliteratorSupplier.get(), c -> c::accept)));
}
private final ImmutableSet>> spliteratorSuppliers;
private SpliteratorTester(ImmutableSet>> spliteratorSuppliers) {
this.spliteratorSuppliers = checkNotNull(spliteratorSuppliers);
}
@SafeVarargs
@CanIgnoreReturnValue
public final Ordered expect(Object... elements) {
return expect(Arrays.asList(elements));
}
@CanIgnoreReturnValue
public final Ordered expect(Iterable elements) {
List> resultsForAllStrategies = new ArrayList<>();
for (Supplier> spliteratorSupplier : spliteratorSuppliers) {
GeneralSpliterator spliterator = spliteratorSupplier.get();
int characteristics = spliterator.characteristics();
long estimatedSize = spliterator.estimateSize();
for (SpliteratorDecompositionStrategy strategy :
SpliteratorDecompositionStrategy.ALL_STRATEGIES) {
List resultsForStrategy = new ArrayList<>();
strategy.forEach(spliteratorSupplier.get(), resultsForStrategy::add);
// TODO(cpovirk): better failure messages
if ((characteristics & Spliterator.NONNULL) != 0) {
assertFalse(resultsForStrategy.contains(null));
}
if ((characteristics & Spliterator.SORTED) != 0) {
Comparator comparator = spliterator.getComparator();
if (comparator == null) {
// A sorted spliterator with no comparator is already using natural order.
// (We could probably find a way to avoid rawtypes here if we wanted.)
@SuppressWarnings({"unchecked", "rawtypes"})
Comparator naturalOrder =
(Comparator) Comparator.naturalOrder();
comparator = naturalOrder;
}
assertTrue(Ordering.from(comparator).isOrdered(resultsForStrategy));
}
if ((characteristics & Spliterator.SIZED) != 0) {
assertEquals(Ints.checkedCast(estimatedSize), resultsForStrategy.size());
}
assertEqualIgnoringOrder(elements, resultsForStrategy);
resultsForAllStrategies.add(resultsForStrategy);
}
}
return new Ordered() {
@Override
public void inOrder() {
for (List resultsForStrategy : resultsForAllStrategies) {
assertEqualInOrder(elements, resultsForStrategy);
}
}
};
}
}
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