IllegalArgumentException.class,
        () -> Traverser.forGraph(createDirectedGraph()).breadthFirst('a'));
  }

  /**
   * Checks that the elements of the iterable are calculated on the fly. Concretely, that means that
   * {@link SuccessorsFunction#successors(Object)} can only be called for a subset of all nodes.
   */
  @Test
  public void forGraph_breadthFirstIterable_emptyGraph() {
    assertEqualCharNodes(

 *   }
 * }
 *
 * <p>With method references it is more succinct: {@code comparing(Foo::aString)} for example.
 *
 * <p>Using {@link Comparator} avoids certain types of bugs, for example when you meant to write
 * {@code .compare(a.foo, b.foo)} but you actually wrote {@code .compare(a.foo, a.foo)} or {@code
 * .compare(a.foo, b.bar)}. {@code ComparisonChain} also has a potential performance problem that

      // path when the first operation on the new map is putAll(otherMap). There, prior to
      // https://github.com/openjdk/jdk/commit/3e393047e12147a81e2899784b943923fc34da8e, a bug
      // meant that sometimes a too-large threshold is calculated. However, this new threshold is
      // independent of the initial capacity, except that it won't be lower than the threshold

      // path when the first operation on the new map is putAll(otherMap). There, prior to
      // https://github.com/openjdk/jdk/commit/3e393047e12147a81e2899784b943923fc34da8e, a bug
      // meant that sometimes a too-large threshold is calculated. However, this new threshold is
      // independent of the initial capacity, except that it won't be lower than the threshold

### Locks

We have 3 different things that we synchronize on.

#### Http2Connection

This lock guards internal state of each connection. This lock is never held for blocking operations. That means that we acquire the lock, read or write a few fields and release the lock. No I/O and no application-layer callbacks.

#### Http2Stream

      // SequentialExecutor by the time the barrier is satisfied
      barrier.await(1, SECONDS);
      executor.execute(barrierTask);
      // timeout means the second task wasn't even tried
      barrier.await(1, SECONDS);
    } finally {
      service.shutdown();
    }
  }

  public void testRejectedExecutionThrownWithMultipleCalls() throws Exception {

    @Nullable ImmutableMapEntry<K, V>[] keyTable = createEntryArray(tableSize);
    @Nullable ImmutableMapEntry<K, V>[] valueTable = createEntryArray(tableSize);
    /*
     * The cast is safe: n==entryArray.length means that we have filled the whole array with Entry
     * instances, in which case it is safe to cast it from an array of nullable entries to an array
     * of non-null entries.
     */
    @SuppressWarnings("nullness")

     * This is an invalid state and should throw an exception.
     */
    @Test
    void testCheck_withNonNullStringAndZeroPointer_throwsException() {
        // A zero pointer should mean the string is null
        PacUnicodeString pacString = new PacUnicodeString((short) 0, (short) 0, 0);
        String testString = "not-null";

        // Expect a PACDecodingException to be thrown

  private lateinit var server: MockWebServer
  private lateinit var client: OkHttpClient

  @BeforeEach
  fun setUp() {
    // Sockets on some platforms can have large buffers that mean writes do not block when
    // required. These socket factories explicitly set the buffer sizes on sockets created.
    server = MockWebServer()
    server.serverSocketFactory =

  }

  /**
   * Ignored due to incompatibilities between Android and Java on how non-ASCII subject alt names
   * are parsed. Android fails to parse these, which means we fall back to the CN. The RI does parse
   * them, so the CN is unused.
   */
  @Test fun verifyNonAsciiSubjectAlt() {
    // Expecting actual:
    //  ["bar.com", "花子.co.jp"]