如何在Spring Batch Junit测试中模拟编写器？

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.springframework.batch.item.ItemWriter;
import org.springframework.batch.test.MetaDataInstanceFactory;
import org.springframework.batch.test.StepScopeTestExecutionListener;
import org.springframework.batch.test.context.SpringBatchTest;
import org.springframework.batch.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.batch.test.step.StepScopeTestUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.TestExecutionListeners;
import org.springframework.test.context.junit4.AbstractTransactionalJUnit4SpringContextTests;
import org.springframework.test.context.junit4.SpringRunner;

import java.util.ArrayList;
import java.util.List;

import static org.mockito.Mockito.*;

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBatchTest
@SpringBootTest
public class MyJobTest {

    @Autowired
    private MyJob myJob;

    @Mock
    private ItemWriter<String> itemWriter;

    @Before
    public void setUp() {
        MockitoAnnotations.initMocks(this);
    }

    @Test
    public void testJob() throws Exception {
        List<String> items = new ArrayList<>();
        items.add("item1");
        items.add("item2");

        StepScopeTestUtils.doInStepScope(MetaDataInstanceFactory.createStepExecution(), () -> {
            when(itemWriter.write(items)).thenReturn(null);

            myJob.execute();

            verify(itemWriter, times(1)).write(items);

            return null;
        });
    }
}