ListenableFuture<O> transform(
          ListenableFuture<I> input, Function<? super I, ? extends O> function, Executor executor) {
    return AbstractTransformFuture.create(input, function, executor);
  }

  /**
   * Like {@link #transform(ListenableFuture, Function, Executor)} except that the transformation
   * {@code function} is invoked on each call to {@link Future#get() get()} on the returned future.
   *

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.function.BiPredicate;
import java.util.stream.Collector;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tester for {@code Collector} implementations.
 *
 * <p>Example usage:
 *
 * <pre>

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Function;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.collect.testing.IteratorFeature;
import com.google.common.collect.testing.IteratorTester;

import java.util.Comparator;
import java.util.Spliterator;
import java.util.function.Consumer;
import java.util.function.DoubleConsumer;
import java.util.function.Function;
import java.util.function.IntConsumer;
import java.util.function.IntFunction;
import java.util.function.LongConsumer;
import java.util.function.Predicate;
import java.util.stream.IntStream;
import javax.annotation.CheckForNull;

            .withFeatures(COLLECTION_FEATURES_REMOVE_ORDER)
            .withFeatures(CollectionFeature.SUPPORTS_ITERATOR_REMOVE)
            .createTestSuite());

    final Function<String, String> removeFirstCharacter =
        new Function<String, String>() {
          @Override
          public String apply(String input) {
            return input.substring(1);
          }
        };

    suite.addTest(

      implements Serializable {
    private final Function<? super A, ? extends B> forwardFunction;
    private final Function<? super B, ? extends A> backwardFunction;

    private FunctionBasedConverter(
        Function<? super A, ? extends B> forwardFunction,
        Function<? super B, ? extends A> backwardFunction) {
      this.forwardFunction = checkNotNull(forwardFunction);

import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Collection;
import java.util.Comparator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.function.Function;
import java.util.stream.Collector;
import java.util.stream.Stream;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Function;
import com.google.common.util.concurrent.ForwardingListenableFuture.SimpleForwardingListenableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ScheduledExecutorService;

    assertSame(not, pool.intern(not));
  }

  public void testAsFunction_simplistic() {
    String canonical = "a";
    String not = new String("a");

    Function<String, String> internerFunction =
        Interners.asFunction(Interners.<String>newStrongInterner());

    assertSame(canonical, internerFunction.apply(canonical));
    assertSame(canonical, internerFunction.apply(not));
  }

import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Equivalence;
import com.google.common.base.Function;
import com.google.common.base.MoreObjects;
import com.google.common.collect.Table.Cell;
import com.google.common.testing.CollectorTester;
import java.util.function.BiPredicate;
import java.util.function.BinaryOperator;
import java.util.stream.Collector;
import java.util.stream.Stream;
import junit.framework.TestCase;