public void testReadEmptyString() throws IOException {
    assertReadsCorrectly("");
  }

  public void testReadsStringsCorrectly() throws IOException {
    assertReadsCorrectly("abc");
    assertReadsCorrectly("abcde");
    assertReadsCorrectly("abcdefghijkl");
    assertReadsCorrectly(
        ""
            + "abcdefghijklmnopqrstuvwxyz\n"
            + "ABCDEFGHIJKLMNOPQRSTUVWXYZ\r"

    String msg = "Alphanumeric characters are always 'safe' and should not be explicitly specified";
    IllegalArgumentException expected =
        assertThrows(IllegalArgumentException.class, () -> new PercentEscaper("-+#abc.!", false));
    assertThat(expected).hasMessageThat().isEqualTo(msg);
  }

  public void testBadArguments_plusforspace() {
    // space can be a safe char if plusForSpace is false

func TestSignV4TrimAll(t *testing.T) {
	testCases := []struct {
		// Input.
		inputStr string
		// Expected result.
		result string
	}{
		{"本語", "本語"},
		{" abc ", "abc"},
		{" a b ", "a b"},
		{"a b ", "a b"},
		{"a  b", "a b"},
		{"a   b", "a b"},
		{"   a   b  c   ", "a b c"},
		{"a \t b  c   ", "a b c"},
		{"\"a \t b  c   ", "\"a b c"},

  private static final ImmutableSet<String> VALID_NAME =
      ImmutableSet.of(
          // keep-sorted start
          "123.cn",
          "8server.shop",
          "a" + DELTA + "b.com",
          "abc.a23",
          "biz.com.ua",
          "f--1.com",
          "f--o",
          "f-_-o.cOM",
          "f11-1.com",
          "fOo",
          "f_a",
          "foo.com",
          "foo.net.us\uFF61ocm",

    val sink1 = stream1.sink.buffer()
    val sink2 = stream2.sink.buffer()
    sink1.writeUtf8("abc")
    assertFailsWith<IOException> {
      sink2.writeUtf8("abc")
      sink2.flush()
    }.also { expected ->
      assertThat(expected.message).isEqualTo("stream was reset: REFUSED_STREAM")
    }
    sink1.writeUtf8("def")
    sink1.close()

  public void testSmallCharMatcher() {
    CharMatcher len1 = SmallCharMatcher.from(bitSet("#"), "#");
    CharMatcher len2 = SmallCharMatcher.from(bitSet("ab"), "ab");
    CharMatcher len3 = SmallCharMatcher.from(bitSet("abc"), "abc");
    CharMatcher len4 = SmallCharMatcher.from(bitSet("abcd"), "abcd");
    assertTrue(len1.matches('#'));
    assertFalse(len1.matches('!'));
    assertTrue(len2.matches('a'));
    assertTrue(len2.matches('b'));

    @DisplayName("readUTF(): decodes bytes after size prefix")
    void readUTF_decodes() throws Exception {
        SmbRandomAccessFile raf = spy(newInstance("r", false, false, false));
        // Size prefix 3, then bytes for "abc"
        doReturn(3).when(raf).readUnsignedShort();
        doAnswer(inv -> {
            byte[] b = inv.getArgument(0);
            int off = inv.getArgument(1);
            b[off] = 'a';

  }

  @SuppressWarnings("unchecked") // functor classes have no type parameters
  public void testGet_functors() {
    assertEquals(0, ArbitraryInstances.get(Comparator.class).compare("abc", 123));
    assertTrue(ArbitraryInstances.get(Predicate.class).apply("abc"));
    assertTrue(ArbitraryInstances.get(Equivalence.class).equivalent(1, 1));
    assertFalse(ArbitraryInstances.get(Equivalence.class).equivalent(1, 2));
  }

		b := NewWriterSize(tw, BufSize)
		b.WriteString("abc")
		tw.check(t, "", "")
		b.WriteString("123456789012345")      // long string, non-empty buffer
		tw.check(t, "abc12345", "6789012345") // use Write and then WriteString since the remaining part is still longer than BufSize
	}
	{
		tw := &teststringwriter{}
		b := NewWriterSize(tw, BufSize)
		b.Write([]byte("abc")) // same as above, but use Write instead of WriteString

AB20..AB26    ; valid                                  # 6.0  ETHIOPIC SYLLABLE CCHHA..ETHIOPIC SYLLABLE CCHHO
AB27          ; disallowed                             # NA   <reserved-AB27>
AB28..AB2E    ; valid                                  # 6.0  ETHIOPIC SYLLABLE BBA..ETHIOPIC SYLLABLE BBO
AB2F          ; disallowed                             # NA   <reserved-AB2F>