assertEquals("abc", StringUtil.substringToLast("abc", "dddd"));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testToHex() throws Exception {
        assertEquals("010203", StringUtil.toHex(new byte[] { 1, 2, 3 }));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testToHex2() throws Exception {
        assertEquals("0001", StringUtil.toHex(1));

            assertEquals(0x0003, combined, "Combined signing flags should equal 0x0003");
        }
    }

    @Nested
    @DisplayName("Dialect Constants")
    class DialectConstants {

        @Test
        @DisplayName("SMB 2.0.2 dialect should be 0x0202")
        void testDialect0202() {
            assertEquals(0x0202, Smb2Constants.SMB2_DIALECT_0202, "SMB 2.0.2 dialect must be 0x0202");

/**
 * Test class for ValidateNegotiateInfoRequest
 */
class ValidateNegotiateInfoRequestTest {

    private static final int DEFAULT_CAPABILITIES = 0x12345678;
    private static final int DEFAULT_SECURITY_MODE = 0x0003;
    private byte[] defaultClientGuid;
    private int[] defaultDialects;

    @BeforeEach
    void setUp() {
        // Initialize default GUID (16 bytes)
        defaultClientGuid = new byte[16];

  public void testJoin() {
    assertThat(Doubles.join(",", EMPTY)).isEmpty();
    assertThat(Doubles.join(",", ARRAY1)).isEqualTo("1.0");
    assertThat(Doubles.join(",", 1.0, 2.0)).isEqualTo("1.0,2.0");
    assertThat(Doubles.join("", 1.0, 2.0, 3.0)).isEqualTo("1.02.03.0");
  }

  public void testJoinNonTrivialDoubles() {
    assertThat(Doubles.join(",", EMPTY)).isEmpty();
    assertThat(Doubles.join(",", 1.2)).isEqualTo("1.2");

  public void testJoin() {
    assertThat(Doubles.join(",", EMPTY)).isEmpty();
    assertThat(Doubles.join(",", ARRAY1)).isEqualTo("1.0");
    assertThat(Doubles.join(",", 1.0, 2.0)).isEqualTo("1.0,2.0");
    assertThat(Doubles.join("", 1.0, 2.0, 3.0)).isEqualTo("1.02.03.0");
  }

  public void testJoinNonTrivialDoubles() {
    assertThat(Doubles.join(",", EMPTY)).isEmpty();
    assertThat(Doubles.join(",", 1.2)).isEqualTo("1.2");

        });
    }

    @Test
    public void testFileOperationOverflow() throws Exception {
        assertThrows(SmbException.class, () -> {
            validator.validateFileOperation(Long.MAX_VALUE - 100, 200, Long.MAX_VALUE);
        });
    }

    @Test
    public void testValidSmbHeader() throws Exception {
        // SMB1 header
        validator.validateSmbHeader(0x424D53FF, 32, 0x72);

    /**
     * Pipe operations should behave like the <code>TransactNamedPipe</code> Win32 Named Pipe function.
     */

    int PIPE_TYPE_TRANSACT = 0x0200;

    /**
     * Pipe is used for DCE
     */
    int PIPE_TYPE_DCE_TRANSACT = 0x0200 | 0x0400;

    /**
     * Pipe should use it's own exclusive transport connection
     */
    int PIPE_TYPE_UNSHARED = 0x800;

    /**

            assertTrue(result.endsWith(",dc=SERVER123]"));

            // Hexdump.toHexString with size = length * 2 produces 8 uppercase hex chars
            // The hex should be "010203FF"
            assertTrue(result.contains("010203FF"));
        }

        @Test
        @DisplayName("toString with empty challenge array")
        void testToStringWithEmptyChallenge() {
            UniAddress dc = mock(UniAddress.class);

    hasher.putBytes(new byte[] {});
    hasher.putBytes(new byte[] {8});
    hasher.assertBytes(expected);
  }

  public void testShort() {
    TestHasher hasher = new TestHasher();
    hasher.putShort((short) 0x0201);
    hasher.assertBytes(new byte[] {1, 2});
  }

  public void testInt() {
    TestHasher hasher = new TestHasher();
    hasher.putInt(0x04030201);
    hasher.assertBytes(new byte[] {1, 2, 3, 4});
  }

    HashCode unused = sink.hash();
    sink.assertInvariants(8);
    sink.assertBytes(expected);
  }

  public void testShort() {
    Sink sink = new Sink(4);
    sink.putShort((short) 0x0201);
    HashCode unused = sink.hash();
    sink.assertInvariants(2);
    sink.assertBytes(new byte[] {1, 2, 0, 0}); // padded with zeros
  }

  public void testInt() {
    Sink sink = new Sink(4);