*/
    @Test
    public void testIsNumver() throws Exception {
        assertFalse(StringUtil.isNumber(null));
        assertTrue(StringUtil.isNumber("0123456789"));
        assertFalse(StringUtil.isNumber("aaaBBBccc"));
        assertFalse(StringUtil.isNumber("０１２３４５６７８９"));
        assertFalse(StringUtil.isNumber(""));
        assertFalse(StringUtil.isNumber("01234abcdef"));
        assertFalse(StringUtil.isNumber("abcdef01234"));

    }

    /**
     * @throws Exception
     */
    @Test
    public void testGetIntField() throws Exception {
        final Field field = getClass().getField("intField");
        final int testData = 1234567890;
        FieldUtil.set(field, this, Integer.valueOf(testData));
        assertThat(FieldUtil.getInt(field, this), is(testData));
    }

    /**
     * @throws Exception
     */
    @Test

        @Test
        @DisplayName("Test expiration property")
        void testExpirationProperty() {
            assertNull(testBlock.getExpiration());
            testBlock.setExpiration(123456789L);
            assertEquals(123456789L, testBlock.getExpiration());
        }
    }

    @Nested
    @DisplayName("DFS Resolution Tests")
    class DFSResolutionTests {

        @BeforeEach
        void setup() {

import java.net.URL;

import org.codelibs.core.net.URLUtil;
import org.junit.Test;

/**
 * @author koichik
 */
public class CopyUtilTest {

    static byte[] srcBytes = new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };

    static String srcString = "ABCDEFGHIJKLMN";

    static String urlString = "あいうえお";

    InputStream is = new ByteArrayInputStream(srcBytes);

    }

    /**
     * Array of hexadecimal digit characters used for converting binary data to hex representation.
     */
    public static final char[] HEX_DIGITS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

    /**
     * This is an alternative to the <code>java.lang.Integer.toHexString</code>
     * method. It is an efficient relative that also will pad the left side so

    // Test all non-escaped ASCII characters.
    String s =
        "!@#$%^*()_+=-/?\\|]}[{,.;:"
            + "abcdefghijklmnopqrstuvwxyz"
            + "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
            + "1234567890";
    assertEquals(s, xmlEscaper.escape(s));

    // Test ASCII control characters.
    for (char ch = 0; ch < 0x20; ch++) {
      if (ch == '\t' || ch == '\n' || ch == '\r') {

    }

    // Edge/null/empty: message-only constructor should propagate message and set unsuccessful status
    @ParameterizedTest
    @NullSource
    @ValueSource(strings = { "", " ", "simple", "with unicode Ω≈ç√", "long-0123456789-abcdefghijklmnopqrstuvwxyz" })
    @DisplayName("Message-only ctor: propagates message and unsuccessful status")
    void messageOnlyConstructor_setsMessage_andUnsuccessfulStatus(String msg) {
        // Arrange & Act

    doTestAllMatches(forPredicate(Predicates.equalTo('c')), "ccc");
    doTestAllMatches(CharMatcher.digit(), "0123456789\u0ED0\u1B59");
    doTestAllMatches(CharMatcher.javaDigit(), "0123456789");
    doTestAllMatches(CharMatcher.digit().and(CharMatcher.ascii()), "0123456789");
    doTestAllMatches(CharMatcher.singleWidth(), "\t0123ABCdef~\u00A0\u2111");
  }

/** Tests for {@code Hashing}. */
@GwtCompatible
@NullMarked
public class HashingTest extends TestCase {
  public void testSmear() {
    assertEquals(1459320713, smear(754102528));
    assertEquals(-160560296, smear(1234567890));
    assertEquals(-1017931171, smear(1));
    assertEquals(-1350072884, smear(-2000000000));
    assertEquals(-809843551, smear(2000000000));
    assertEquals(-309370926, smear(-1155484576));

        assertEquals("FFFFFFFFFFFFFFFF", Hexdump.toHexString(-1L, 16));

        // Test different sizes
        assertEquals("00000000", Hexdump.toHexString(0L, 8));
        assertEquals("12345678", Hexdump.toHexString(0x12345678L, 8));
    }

    @Test
    @DisplayName("Should handle special byte values correctly")
    void testSpecialByteValues() {
        // Test boundary values