* does not include "was cancelled." To be explicit: If this method returns a non-null value,
   * then:
   *
   * <ul>
   *   <li>{@code isDone()} must return {@code true}
   *   <li>{@code isCancelled()} must return {@code false}
   *   <li>{@code get()} must not block, and it must throw an {@code ExecutionException} with the
   *       return value of this method as its cause
   * </ul>
   */
  public static

   * to create a <i>new</i> supplier just to pass it in here; just subclass {@code CacheLoader} and
   * implement {@link #load load} instead.
   *
   * <p>The returned object is serializable if {@code supplier} is serializable.
   *
   * @param supplier the supplier to be used for loading values; must never return {@code null}

  1. Any significant changes should be accompanied by tests. The project already
     has good test coverage, so look at some existing tests if you're unsure
     how to go about it.
  2. All contributions must be licensed Apache 2.0 and all files must have a
     copy of the boilerplate license comment (can be copied from an existing
     file).
  3. Files should be formatted according to Google's [Java style guide][].

    assertWithTemplate(
        "$ITEM must be $RELATIONSHIP to $OTHER",
        itemInfo,
        relatedInfo,
        equivalence.equivalent(item, related));

    int itemHash = equivalence.hash(item);
    int relatedHash = equivalence.hash(related);
    assertWithTemplate(
        "the $HASH ("
            + itemHash
            + ") of $ITEM must be equal to the $HASH ("
            + relatedHash

 * {@link #putString(CharSequence, Charset)} is generally only useful for cross-language
 * compatibility (otherwise prefer {@link #putUnencodedChars}). However, the character encodings
 * must be identical across languages. Also beware that {@link Charset} definitions may occasionally
 * change between Java releases.
 *
 * <p><b>Warning:</b> Chunks of data that are put into the {@link Hasher} are not delimited. The

    checkNotNull(target);
    checkNotNull(interfaceType);
    checkNotNull(timeoutUnit);
    checkPositiveTimeout(timeoutDuration);
    checkArgument(interfaceType.isInterface(), "interfaceType must be an interface type");

    Set<Method> interruptibleMethods = findInterruptibleMethods(interfaceType);

    InvocationHandler handler =
        new InvocationHandler() {
          @Override
          @CheckForNull

  }

  /**
   * {@inheritDoc}
   *
   * <p>By default, returns the supplied elements in their given order; however, generators for
   * containers with a known order other than insertion order must override this method.
   *
   * <p>Note: This default implementation is overkill (but valid) for an unordered container. An
   * equally valid implementation for an unordered container is to throw an exception. The chosen

  }

  /**
   * {@inheritDoc}
   *
   * <p>By default, returns the supplied elements in their given order; however, generators for
   * containers with a known order other than insertion order must override this method.
   *
   * <p>Note: This default implementation is overkill (but valid) for an unordered container. An
   * equally valid implementation for an unordered container is to throw an exception. The chosen

      assertTrue(item + " must not be Object#equals to null", !item.equals(null));
      assertTrue(
          item + " must not be Object#equals to an arbitrary object of another class",
          !item.equals(NotAnInstance.EQUAL_TO_NOTHING));
      assertTrue(item + " must be Object#equals to itself", item.equals(item));
      assertEquals(
          "the Object#hashCode of " + item + " must be consistent",
          item.hashCode(),

import com.google.common.collect.testing.Helpers;
import java.util.Collections;
import java.util.Set;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Encapsulates the constraints that a class under test must satisfy in order for a tester method to
 * be run against that class.
 *
 * @author George van den Driessche
 */
@GwtCompatible
public final class TesterRequirements {
  private final Set<Feature<?>> presentFeatures;