private static final class RoundToDoubleTester {
    private final BigInteger input;
    private final Map<RoundingMode, Double> expectedValues = new EnumMap<>(RoundingMode.class);
    private boolean unnecessaryShouldThrow = false;

    RoundToDoubleTester(BigInteger input) {
      this.input = input;
    }

    @CanIgnoreReturnValue

/**
 * Tests for {@link HostAndPort}
 *
 * @author Paul Marks
 */
@GwtCompatible
@NullUnmarked
public class HostAndPortTest extends TestCase {

  public void testFromStringWellFormed() {
    // Well-formed inputs.
    checkFromStringCase("google.com", 80, "google.com", 80, false);
    checkFromStringCase("google.com", 80, "google.com", 80, false);
    checkFromStringCase("192.0.2.1", 82, "192.0.2.1", 82, false);

/**
 * Tests for {@link HostAndPort}
 *
 * @author Paul Marks
 */
@GwtCompatible
@NullUnmarked
public class HostAndPortTest extends TestCase {

  public void testFromStringWellFormed() {
    // Well-formed inputs.
    checkFromStringCase("google.com", 80, "google.com", 80, false);
    checkFromStringCase("google.com", 80, "google.com", 80, false);
    checkFromStringCase("192.0.2.1", 82, "192.0.2.1", 82, false);

  public void testRepeat() {
    String input = "20";
    assertEquals("", Strings.repeat(input, 0));
    assertEquals("20", Strings.repeat(input, 1));
    assertEquals("2020", Strings.repeat(input, 2));
    assertEquals("202020", Strings.repeat(input, 3));

    assertEquals("", Strings.repeat("", 4));

    for (int i = 0; i < 100; ++i) {
      assertEquals(2 * i, Strings.repeat(input, i).length());
    }

    for (Map.Entry<K, V> entry : map.entrySet()) {
      stream.writeObject(entry.getKey());
      stream.writeObject(entry.getValue());
    }
  }

  /**
   * Populates a map by reading an input stream, as part of deserialization. See {@link #writeMap}
   * for the data format.
   */
  static <K extends @Nullable Object, V extends @Nullable Object> void populateMap(

  }

  public void testGrowBuffer() { // need to grow past an initial 1024 byte buffer
    StringBuilder input = new StringBuilder();
    StringBuilder expected = new StringBuilder();
    for (int i = 256; i < 1024; i++) {
      input.append((char) i);
      expected.append("[" + i + "]");
    }
    assertThat(SIMPLE_ESCAPER.escape(input.toString())).isEqualTo(expected.toString());
  }

  public void testSurrogatePairs() {

  }

  public void testGrowBuffer() { // need to grow past an initial 1024 byte buffer
    StringBuilder input = new StringBuilder();
    StringBuilder expected = new StringBuilder();
    for (int i = 256; i < 1024; i++) {
      input.append((char) i);
      expected.append("[" + i + "]");
    }
    assertThat(SIMPLE_ESCAPER.escape(input.toString())).isEqualTo(expected.toString());
  }

  public void testSurrogatePairs() {

    /**
     * Creates a {@link Reader} to read from a file with the specified encoding.
     *
     * @param is
     *            the input stream (must not be {@literal null})
     * @param encoding
     *            the encoding of the input stream (must not be {@literal null} or empty)
     * @return a {@link Reader} to read from the file
     */

   * Returns an output {@code Future} to use in place of the given {@code input}. The output {@code
   * Future} need not be {@linkplain Future#isDone done}, making {@code AsyncFunction} suitable for
   * asynchronous derivations.
   *
   * <p>Throwing an exception from this method is equivalent to returning a failing {@code Future}.
   */
  ListenableFuture<O> apply(@ParametricNullness I input) throws Exception;

    assertFailsToDecode(base64(), "12345", "Invalid input length 5");
    // These have a combination of invalid length, unrecognized characters and wrong padding.
    assertFailsToDecode(base64(), "AB=C", "Unrecognized character: =");
    assertFailsToDecode(base64(), "A=BCD", "Invalid input length 5");
    assertFailsToDecode(base64(), "?", "Invalid input length 1");
  }

  public void testBase64CannotUpperCase() {