@Override
  protected Set<StepField> getUsedFields( ExcelInputMeta meta ) {
    Set<StepField> usedFields = new HashSet<>();
    if ( meta.isAcceptingFilenames() && StringUtils.isNotEmpty( meta.getAcceptingStepName() ) ) {
      StepField stepField = new StepField( meta.getAcceptingStepName(), meta.getAcceptingField() );
      usedFields.add( stepField );
    }
    return usedFields;
  }
@Test
  public void testGetUsedFields_fileNameFromField() throws Exception {
    lenient().when( meta.isAcceptingFilenames() ).thenReturn( true );
    lenient().when( meta.getAcceptingField() ).thenReturn( "filename" );
    lenient().when( meta.getAcceptingStepName() ).thenReturn( "previousStep" );
    Set<StepField> usedFields = analyzer.getUsedFields( meta );
    assertNotNull( usedFields );
    assertEquals( 1, usedFields.size() );
    StepField used = usedFields.iterator().next();
    assertEquals( "previousStep", used.getStepName() );
    assertEquals( "filename", used.getFieldName() );
  }