}
        };
    try {
      Hashing.hmacMd5(badKey);
      fail();
    } catch (IllegalArgumentException expected) {
    } catch (NullPointerException toleratedOnAndroid) {
      // TODO(cpovirk): In an ideal world, we'd check here that we're running on Android.
    }
  }

  public void testEmptyInputs() throws Exception {
    String knownOutput = "8cbf764cbe2e4623d99a41354adfd390";

      checkNonNegative(--successorCount);

      if (orderedNodeConnections != null) {
        orderedNodeConnections.remove(new NodeConnection.Succ<>((N) node));
      }
    }

    /*
     * TODO(cpovirk): `return (V) removedValue` once our checker permits that.
     *
     * (We promoted a class of warnings into errors because sometimes they indicate real problems.

        .forAllPublicStaticMethods(Suppliers.class)
        .testNulls();
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection
  @AndroidIncompatible // TODO(cpovirk): ClassNotFoundException: com.google.common.base.Function
  @SuppressWarnings("Java7ApiChecker") // includes test of Java 8+ API
  public void testSuppliersSerializable() throws Exception {
    new ClassSanityTester()

            new TestStringSortedMapGenerator() {
              @Override
              protected SortedMap<String, String> create(Entry<String, String>[] entries) {
                /*
                 * TODO(cpovirk): it would be nice to create an input Map and use
                 * the copy constructor here and in the other tests
                 */
                return populate(new TreeMap<String, String>(), entries);

        .forAllPublicStaticMethods(Suppliers.class)
        .testNulls();
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection
  @AndroidIncompatible // TODO(cpovirk): ClassNotFoundException: com.google.common.base.Function
  @SuppressWarnings("Java7ApiChecker") // includes test of Java 8+ API
  public void testSuppliersSerializable() throws Exception {
    new ClassSanityTester()

    // first range closed end, second range closed start
    assertEquals(Range.open(2, 4), Range.atMost(2).gap(closedRange));
    assertEquals(Range.open(2, 4), closedRange.gap(Range.atMost(2)));
  }

  // TODO(cpovirk): More extensive testing of gap().

  public void testSpan_general() {
    Range<Integer> range = Range.closed(4, 8);

    // separate below
    assertEquals(Range.closed(0, 8), range.span(Range.closed(0, 2)));

          while (top.hasNext()) {
            N element = top.next();
            // requireNonNull is safe because horizon contains only graph nodes.
            /*
             * TODO(cpovirk): Replace these two statements with one (`N element =
             * requireNonNull(top.next())`) once our checker supports it.
             *
             * (The problem is likely

  }

  /**
   * Creates and returns a new builder, configured to build {@code MinMaxPriorityQueue} instances
   * that use {@code comparator} to determine the least and greatest elements.
   */
  /*
   * TODO(cpovirk): Change to Comparator<? super B> to permit Comparator<@Nullable ...> and
   * Comparator<SupertypeOfB>? What we have here matches the immutable collections, but those also

/**
 * Unit tests for {@code Ordering}.
 *
 * @author Jesse Wilson
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public class OrderingTest extends TestCase {
  // TODO(cpovirk): some of these are inexplicably slow (20-30s) under GWT

  private final Ordering<Number> numberOrdering = new NumberOrdering();

  public void testAllEqual() {

/**
 * Unit tests for {@code Ordering}.
 *
 * @author Jesse Wilson
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public class OrderingTest extends TestCase {
  // TODO(cpovirk): some of these are inexplicably slow (20-30s) under GWT

  private final Ordering<Number> numberOrdering = new NumberOrdering();

  public void testAllEqual() {