@Test
 public void testZSS502_NonExistingSheet2007() {
   Book book = Util.loadBook(this, "book/blank.xlsx");
   Sheet sheet = book.getSheetAt(0);
   Range cell = Ranges.range(sheet, "A1");
   cell.setCellEditText("=nonExisted!B1");
   assertEquals("=nonExisted!B1", cell.getCellEditText());
   assertEquals(ErrorConstants.getText(ErrorConstants.ERROR_REF), cell.getCellFormatText());
 }
  @Test
  public void testZSS502_2007() {
    Book book = Util.loadBook(this, "book/502-crossSheetReference.xlsx");
    Sheet sheet = book.getSheet("cell-reference");
    Range referencingCell = Ranges.range(sheet, "C4");
    assertEquals("=row!A1", referencingCell.getCellEditText());
    assertEquals("The first row is freezed.", referencingCell.getCellFormatText());

    Ranges.range(book.getSheet("row")).deleteSheet();

    assertEquals("='#REF'!A1", referencingCell.getCellEditText());
    assertEquals(
        ErrorConstants.getText(ErrorConstants.ERROR_REF), referencingCell.getCellFormatText());
  }
 // 20120117, [email protected]: return extern book in book index
 // ZSS-81 Cannot input formula with proper external book name
 @Override
 public String toInternalFormulaString(FormulaRenderingWorkbook book) {
   return ExternSheetNameResolver.prependInternalSheetName(
       book, field_1_index_extern_sheet, ErrorConstants.getText(ErrorConstants.ERROR_REF));
 }