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];

            when(mockConfig.isRequireSecureNegotiate()).thenReturn(true);
            when(mockDigest.verify(buffer, 0, 100, 0, response)).thenReturn(false);

            boolean result = response.verifySignature(buffer, 0, 100);

            assertTrue(result);
            verify(mockDigest).verify(buffer, 0, 100, 0, response);
        }
    }

    @Nested
    @DisplayName("Expiration Tests")
    class ExpirationTests {

            testGuid[i] = (byte) (i + 1);
        }
        System.arraycopy(testGuid, 0, buffer, bufferIndex + 4, 16);

        // Set security mode (2 bytes)
        int testSecurityMode = 0x0003;
        SMBUtil.writeInt2(testSecurityMode, buffer, bufferIndex + 20);

        // Set dialect (2 bytes)
        int testDialect = 0x0311;
        SMBUtil.writeInt2(testDialect, buffer, bufferIndex + 22);

     */
    @Test
    void testPipeTypeTransact() {
        assertEquals(0x0200, SmbPipeResource.PIPE_TYPE_TRANSACT, "PIPE_TYPE_TRANSACT should be 0x0200");
    }

    /**
     * Test if the PIPE_TYPE_DCE_TRANSACT constant has the correct value.
     */
    @Test
    void testPipeTypeDceTransact() {
        assertEquals(0x0200 | 0x0400, SmbPipeResource.PIPE_TYPE_DCE_TRANSACT, "PIPE_TYPE_DCE_TRANSACT should be 0x0600");
    }

            testBlock.setDigest(mockDigest);
            testBlock.setErrorCode(0);
            byte[] buffer = new byte[100];

            when(mockDigest.verify(buffer, 0, 100, 0, testBlock)).thenReturn(false);

            assertTrue(testBlock.verifySignature(buffer, 0, 100));
            assertFalse(testBlock.isVerifyFailed());
        }

        @Test
        @DisplayName("Test verify signature failure")

        });
    }

    @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);

        // Check information level (FS_SIZE_INFO maps to 0x0103)
        int actualInfoLevel = SMBUtil.readInt2(buffer, 0);
        assertEquals(0x0103, actualInfoLevel);
    }

    @DisplayName("Test writeParametersWireFormat with different information levels")
    @ParameterizedTest
    @CsvSource({ "-1, 1", // SMB_INFO_ALLOCATION -> 0x0001
            "3, 259" // FS_SIZE_INFO -> 0x0103
    })

            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);