fail("mismatch at index " + i + ": " + reportContext(expectedList));
      }
    }
  }

  /**
   * Used to delay string formatting until actually required, as it otherwise shows up in the test
   * execution profile when running an extremely large numbers of tests.
   */
  private String reportContext(List<E> expected) {
    return Platform.format(

      runnables = null; // allow GC to free listeners even if this stays around for a while.
    }
    // If we succeeded then list holds all the runnables we to execute. The pairs in the stack are
    // in the opposite order from how they were added so we need to reverse the list to fulfill our
    // contract.
    // This is somewhat annoying, but turns out to be very fast in practice. Alternatively, we could

 *       }
 *     };
 * iteratorTester.test();
 * iteratorTester.testForEachRemaining();
 * }</pre>
 *
 * <p><b>Note</b>: It is necessary to use {@code IteratorTester.KnownOrder} as shown above, rather
 * than {@code KnownOrder} directly, because otherwise the code cannot be compiled.
 *
 * @author Kevin Bourrillion
 * @author Chris Povirk
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A simplistic set which implements the bare minimum so that it can be used in tests without
 * relying on any specific Set implementations. Slow. Explicitly allows null elements so that they
 * can be used in the testers.
 *
 * @author Regina O'Dell
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A simplistic set which implements the bare minimum so that it can be used in tests without
 * relying on any specific Set implementations. Slow. Explicitly allows null elements so that they
 * can be used in the testers.
 *
 * @author Regina O'Dell
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

/** Tests for {@link AbstractSequentialIterator}. */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public class AbstractSequentialIteratorTest extends TestCase {
  @GwtIncompatible // Too slow
  public void testDoublerExhaustive() {
    new IteratorTester<Integer>(
        3, UNMODIFIABLE, ImmutableList.of(1, 2), IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override

       * pass.
       *
       * 2. We would probably choose to compare exceptions using == instead of equals() (for
       * consistency with how weak references are cleared). That's a behavior change -- arguably the
       * removal of a feature.
       *
       * Fortunately, exceptions rarely contain references to expensive resources.
       */

      //

import java.util.Map;
import java.util.Map.Entry;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.junit.Ignore;

/**
 * Base class for map testers.
 *
 * <p>TODO: see how much of this is actually needed once Map testers are written. (It was cloned
 * from AbstractCollectionTester.)
 *
 * @param <K> the key type of the map to be tested.
 * @param <V> the value type of the map to be tested.

    other helpful links

## Links

-   [GitHub project](https://github.com/google/guava)
-   [Issue tracker: Report a defect or feature request](https://github.com/google/guava/issues/new)
-   [StackOverflow: Ask "how-to" and "why-didn't-it-work" questions](https://stackoverflow.com/questions/ask?tags=guava+java)
-   [guava-announce: Announcements of releases and upcoming significant changes](https://groups.google.com/group/guava-announce)

/** Tests for {@link AbstractSequentialIterator}. */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public class AbstractSequentialIteratorTest extends TestCase {
  @GwtIncompatible // Too slow
  public void testDoublerExhaustive() {
    new IteratorTester<Integer>(
        3, UNMODIFIABLE, ImmutableList.of(1, 2), IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override