Cell cfs = r.createCell(3, Cell.CELL_TYPE_FORMULA);
cfs.setCellFormula("B1");
FormulaEvaluator fe = wb.getCreationHelper().createFormulaEvaluator();
assertEquals(Cell.CELL_TYPE_NUMERIC, fe.evaluate(cfn).getCellType());
assertEquals(Cell.CELL_TYPE_STRING, fe.evaluate(cfs).getCellType());
fe.evaluateFormulaCell(cfn);
fe.evaluateFormulaCell(cfs);
// Now test
assertEquals(Cell.CELL_TYPE_NUMERIC, cn.getCellType());