// Simulate different encode return values
            when(mockChunk1.encode(any(byte[].class), anyInt())).thenReturn(20);
            when(mockChunk2.encode(any(byte[].class), anyInt())).thenReturn(24);
            when(mockChunk3.encode(any(byte[].class), anyInt())).thenReturn(22);

            SrvCopychunkCopy copy = new SrvCopychunkCopy(sourceKey, mockChunk1, mockChunk2, mockChunk3);

        verify(mockDeferredNdrBuffer, times(9)).enc_ndr_long(anyInt()); // 3 enc_ndr_long for each of 3 unicode strings
        verify(mockDeferredNdrBuffer, times(3)).enc_ndr_long(0);
        verify(mockDeferredNdrBuffer, times(3)).advance(anyInt());
        verify(mockDeferredNdrBuffer, times(4)).derive(anyInt()); // 3 for strings + 1 for guid

import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.Mockito.doReturn;
import static org.mockito.Mockito.spy;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;

import org.junit.jupiter.api.BeforeEach;

        assertEquals("Invalid token", ex.getMessage());

        // Ensure mechContext was not engaged due to early failure
        verify(this.mechContext, never()).initSecContext(any(), anyInt(), anyInt());
    }

    @Test
    @DisplayName("initSecContext with null buffer and non-zero len throws NPE")
    void testInitSecContextNullBufferNonZeroLen() throws Exception {

import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.doReturn;
import static org.mockito.Mockito.doThrow;
import static org.mockito.Mockito.lenient;
import static org.mockito.Mockito.spy;

import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import java.net.UnknownHostException;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import java.lang.reflect.Field;

import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import java.util.Properties;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.DisplayName;

            assertTrue(result);
            assertFalse(echoResponse.isVerifyFailed());
            verify(mockDigest, never()).verify(any(), anyInt(), anyInt(), anyInt(), any());
        }
    }

    @Nested
    @DisplayName("Credit Management Tests")
    class CreditManagementTests {

        @Test

import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.ArgumentMatchers.eq;
import static org.mockito.Mockito.inOrder;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.reset;