[bug-64508] add guard for invalid v value

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1879905 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -105,6 +105,7 @@ import org.apache.poi.xssf.model.CalculationChain;
 import org.apache.poi.xssf.streaming.SXSSFWorkbook;
 import org.apache.poi.xssf.usermodel.extensions.XSSFCellFill;
 import org.apache.xmlbeans.XmlException;
+import org.junit.Assert;
 import org.junit.Ignore;
 import org.junit.Test;
 import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTCalcCell;
@@ -3546,4 +3547,17 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             }
         }
     }
+
+    @Test
+    public void testBug64508() throws IOException {
+        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("64508.xlsx")) {
+            int activeSheet = wb.getActiveSheetIndex();
+            Sheet sheet1 = wb.getSheetAt(activeSheet);
+            Row row = sheet1.getRow(1);
+            CellReference aCellReference = new CellReference("E2");
+            Cell aCell = row.getCell(aCellReference.getCol());
+            Assert.assertEquals(CellType.STRING, aCell.getCellType());
+            Assert.assertEquals("", aCell.getStringCellValue());
+        }
+    }
 }