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   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
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       http://www.apache.org/licenses/LICENSE-2.0

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   distributed under the License is distributed on an "AS IS" BASIS,
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   See the License for the specific language governing permissions and
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package org.apache.poi.ss.formula.functions;

import junit.framework.TestCase;
import junit.framework.AssertionFailedError;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.hssf.HSSFTestDataSamples;
import org.apache.poi.ss.usermodel.CellValue;

/**
 * Tests for {@link Npv}
 *
 * @author Marcel May
 * @see <a href="http://office.microsoft.com/en-us/excel-help/npv-HP005209199.aspx">Excel Help</a>
 */
public final class TestNpv extends TestCase {

    public void testEvaluateInSheetExample2() {
        HSSFWorkbook wb = new HSSFWorkbook();
        HSSFSheet sheet = wb.createSheet("Sheet1");
        HSSFRow row = sheet.createRow(0);

        sheet.createRow(1).createCell(0).setCellValue(0.08d);
        sheet.createRow(2).createCell(0).setCellValue(-40000d);
        sheet.createRow(3).createCell(0).setCellValue(8000d);
        sheet.createRow(4).createCell(0).setCellValue(9200d);
        sheet.createRow(5).createCell(0).setCellValue(10000d);
        sheet.createRow(6).createCell(0).setCellValue(12000d);
        sheet.createRow(7).createCell(0).setCellValue(14500d);

        HSSFCell cell = row.createCell(8);
        HSSFFormulaEvaluator fe = new HSSFFormulaEvaluator(wb);

        // Enumeration
        cell.setCellFormula("NPV(A2, A4,A5,A6,A7,A8)+A3");
        fe.clearAllCachedResultValues();
        fe.evaluateFormulaCellEnum(cell);
        double res = cell.getNumericCellValue();
        assertEquals(1922.06d, Math.round(res * 100d) / 100d);

        // Range
        cell.setCellFormula("NPV(A2, A4:A8)+A3");

        fe.clearAllCachedResultValues();
        fe.evaluateFormulaCellEnum(cell);
        res = cell.getNumericCellValue();
        assertEquals(1922.06d, Math.round(res * 100d) / 100d);
    }

    /**
     * evaluate formulas with NPV and compare the result with
     * the cached formula result pre-calculated by Excel
     */
    public void testNpvFromSpreadsheet(){
        HSSFWorkbook wb = HSSFTestDataSamples.openSampleWorkbook("IrrNpvTestCaseData.xls");
        HSSFSheet sheet = wb.getSheet("IRR-NPV");
        HSSFFormulaEvaluator fe = new HSSFFormulaEvaluator(wb);
        StringBuffer failures = new StringBuffer();
        int failureCount = 0;
        // TODO YK: Formulas in rows 16 and 17 operate with ArrayPtg which isn't yet supported
        // FormulaEvaluator as of r1041407 throws "Unexpected ptg class (org.apache.poi.ss.formula.ptg.ArrayPtg)"
        for(int rownum = 9; rownum <= 15; rownum++){
            HSSFRow row = sheet.getRow(rownum);
            HSSFCell cellB = row.getCell(1);
            try {
                CellValue cv = fe.evaluate(cellB);
                assertFormulaResult(cv, cellB);
            } catch (Throwable e){
                if(failures.length() > 0) failures.append('\n');
                failures.append("Row[" + (cellB.getRowIndex() + 1)+ "]: " + cellB.getCellFormula() + " ");
                failures.append(e.getMessage());
                failureCount++;
            }
        }

        if(failures.length() > 0) {
            throw new AssertionFailedError(failureCount + " IRR evaluations failed:\n" + failures.toString());
        }
    }

    private static void assertFormulaResult(CellValue cv, HSSFCell cell){
        double actualValue = cv.getNumberValue();
        double expectedValue = cell.getNumericCellValue(); // cached formula result calculated by Excel
        assertEquals(expectedValue, actualValue, 1E-4); // should agree within 0.01%
    }
}