// Write the mocking script.
    peer.sendFrame().settings(Settings())
    peer.sendFrame().headers(true, 3, headerEntries("client", "abc"))
    peer.acceptFrame() // ACK
    peer.acceptFrame() // HEADERS STREAM 3
    peer.acceptFrame() // DATA STREAM 3 "abcde"
    peer.acceptFrame() // HEADERS STREAM 3
    peer.play()

    // Play it back.
    val connection = connect(peer)

      String.valueOf(Character.MIN_LOW_SURROGATE),
      Character.MIN_LOW_SURROGATE + "xyz",
      "abc" + Character.MIN_LOW_SURROGATE,
      "abc" + Character.MIN_LOW_SURROGATE + "xyz",
      String.valueOf(Character.MAX_LOW_SURROGATE),
      Character.MAX_LOW_SURROGATE + "xyz",
      "abc" + Character.MAX_LOW_SURROGATE,
      "abc" + Character.MAX_LOW_SURROGATE + "xyz",
    };
    for (String s : BAD_STRINGS) {

        value = "${abc.xyz}";
        assertEquals(value, ResourceUtil.resolve(value));

        System.setProperty("abc.xyz", "789");

        value = "${abc.xyz}";
        assertEquals("789", ResourceUtil.resolve(value));

        value = "${abc}${abc.xyz}";
        assertEquals("123789", ResourceUtil.resolve(value));

        value = "xxx${abc.xyz}zzz";
        assertEquals("xxx789zzz", ResourceUtil.resolve(value));

        assertEquals("", StringUtil.substringToLast("abc", "c"));
        assertEquals("c", StringUtil.substringToLast("abc", "b"));
        assertEquals("c", StringUtil.substringToLast("abcbc", "b"));
        assertEquals("abc", StringUtil.substringToLast("abc", ""));
        assertEquals("abc", StringUtil.substringToLast("abc", null));
        assertEquals("abc", StringUtil.substringToLast("abc", "dddd"));
    }

    /**

        String result = chain.normalize("ａｂｃ", "field");

        assertEquals("abc", result);
    }

    @Test
    public void test_multipleNormalizers() throws Exception {
        NormalizerChain chain = new NormalizerChain();
        chain.add(new FullWidthToHalfWidthAlphabetNormalizer());
        chain.add(new HankakuKanaToZenkakuKana());

        String result = chain.normalize("ａｂｃ ｶﾞ", "field");

  }

  public void testEmptiesFirst() {
    Optional<String> empty = Optional.empty();
    Optional<String> abc = Optional.of("abc");
    Optional<String> z = Optional.of("z");

    Comparator<Optional<String>> comparator = emptiesFirst(comparing(String::length));
    testComparator(comparator, empty, z, abc);

    // Just demonstrate that no explicit type parameter is required

        "/form-json-list", data={"items": json.dumps(["abc", "def"])}
    )
    assert response.status_code == 200, response.text
    assert response.json() == ["abc", "def"]


def test_query_json_list():
    response = client.get(
        "/query-json-list", params={"items": json.dumps(["abc", "def"])}
    )
    assert response.status_code == 200, response.text
    assert response.json() == ["abc", "def"]


def test_header_json_list():

    //     smaller version of the same problem.
    //     Say we are rotating abcdefgh by 5. We start with abcde|fgh. The smaller block is [fgh]:
    //     [abc]de|[fgh] -> [fgh]de|[abc]. Now [fgh] is in the right place, but we need to swap [de]
    //     with [abc]: fgh[de]|a[bc] -> fgh[bc]|a[de]. Now we need to swap [a] with [bc]:
    //     fgh[b]c|[a]de -> fgh[a]c|[b]de. Finally we need to swap [c] with [b]:

  }

  public void testEmptiesFirst() {
    Optional<String> empty = Optional.empty();
    Optional<String> abc = Optional.of("abc");
    Optional<String> z = Optional.of("z");

    Comparator<Optional<String>> comparator = emptiesFirst(comparing(String::length));
    testComparator(comparator, empty, z, abc);

    // Just demonstrate that no explicit type parameter is required

    assertEquals(java.util.Optional.of("abc"), Optional.toJavaUtil(Optional.of("abc")));
  }

  public void testToJavaUtil_instance() {
    assertEquals(java.util.Optional.empty(), Optional.absent().toJavaUtil());
    assertEquals(java.util.Optional.of("abc"), Optional.of("abc").toJavaUtil());
  }

  @SuppressWarnings("NullOptional")
  public void testFromJavaUtil() {