allow overridden built-in formats in XSSFCellStyle, see Bugzilla 49928

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1005726 13f79535-47bb-0310-9956-ffa450edef68

src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFDataFormat.java

      * @return string represented at index of format or null if there is not a  format at that index
      */
     public String getFormat(short index) {
-        String fmt = BuiltinFormats.getBuiltinFormat(index);
-        if(fmt == null) fmt = stylesSource.getNumberFormatAt(index);
+        String fmt = stylesSource.getNumberFormatAt(index);
+        if(fmt == null) fmt = BuiltinFormats.getBuiltinFormat(index);
         return fmt;
     }
 }

src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFDataFormat.java

 package org.apache.poi.xssf.usermodel;
 
 import org.apache.poi.ss.usermodel.BaseTestDataFormat;
+import org.apache.poi.ss.usermodel.BuiltinFormats;
+import org.apache.poi.ss.usermodel.DataFormatter;
 import org.apache.poi.xssf.XSSFITestDataProvider;
+import org.apache.poi.xssf.XSSFTestDataSamples;
 
 /**
  * Tests for {@link XSSFDataFormat}
 	public TestXSSFDataFormat() {
 		super(XSSFITestDataProvider.instance);
 	}
+
+    /**
+     * [Bug 49928] formatCellValue returns incorrect value for \u00a3 formatted cells
+     */
+    public void test49928(){
+        XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("49928.xlsx");
+        DataFormatter df = new DataFormatter();
+
+        XSSFSheet sheet = wb.getSheetAt(0);
+        XSSFCell cell = sheet.getRow(0).getCell(0);
+        XSSFCellStyle style = cell.getCellStyle();
+
+        String poundFmt = "\"\u00a3\"#,##0;[Red]\\-\"\u00a3\"#,##0";
+        // not expected normally, id of a custom format should be gerater 
+        // than BuiltinFormats.FIRST_USER_DEFINED_FORMAT_INDEX
+        short  poundFmtIdx = 6;
+
+        assertEquals(poundFmt, style.getDataFormatString());
+        assertEquals(poundFmtIdx, style.getDataFormat());
+        assertEquals("\u00a31", df.formatCellValue(cell));
+
+
+        XSSFDataFormat dataFormat = wb.createDataFormat();
+        assertEquals(poundFmtIdx, dataFormat.getFormat(poundFmt));
+        assertEquals(poundFmt, dataFormat.getFormat(poundFmtIdx));
+
+        // an attempt to register an existing format returns its index
+        assertEquals(poundFmtIdx, wb.getStylesSource().putNumberFormat(poundFmt));
+
+        // now create a custom format with Pound (\u00a3)
+        short customFmtIdx = dataFormat.getFormat("\u00a3##.00[Yellow]");
+        assertTrue(customFmtIdx > BuiltinFormats.FIRST_USER_DEFINED_FORMAT_INDEX );
+        assertEquals("\u00a3##.00[Yellow]", dataFormat.getFormat(customFmtIdx));
+
+    }
 }