diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFDataFormat.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFDataFormat.java
index ba89baed3d..63faef0c91 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFDataFormat.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFDataFormat.java
@@ -31,6 +31,7 @@ import org.apache.poi.ss.usermodel.CellStyle;
 import org.apache.poi.ss.usermodel.DataFormat;
 import org.apache.poi.ss.usermodel.DataFormatter;
 import org.apache.poi.ss.usermodel.FormulaEvaluator;
+import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.usermodel.Workbook;
 import org.apache.poi.ss.util.CellReference;
 import org.apache.poi.xssf.XSSFITestDataProvider;
@@ -148,7 +149,7 @@ public final class TestXSSFDataFormat extends BaseTestDataFormat {
             assertEquals("TRUE", df.formatCellValue(cell));
 
             CellStyle cellStyle = wb.createCellStyle();
-            cellStyle.setDataFormat((short)14);
+            cellStyle.setDataFormat((short) 14);
             cell.setCellStyle(cellStyle);
             cell.setCellValue(new Date(234092383));
             assertEquals("1/3/70", df.formatCellValue(cell));
@@ -159,5 +160,19 @@ public final class TestXSSFDataFormat extends BaseTestDataFormat {
             */
         }
     }
-    
+
+    @Test
+    public void testGitHub650() throws IOException {
+        // https://github.com/apache/poi/pull/650
+        DataFormatter df = new DataFormatter();
+
+        try (Workbook wb = _testDataProvider.openSampleWorkbook("decimal-format.xlsx")) {
+            Sheet sheet = wb.getSheetAt(0);
+            Cell cell1 = sheet.getRow(0).getCell(0);
+            assertEquals("1.01", df.formatCellValue(cell1));
+            Cell cell2 = sheet.getRow(1).getCell(0);
+            assertEquals("1.00", df.formatCellValue(cell2));
+        }
+    }
+
 }
diff --git a/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestDataFormat.java b/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestDataFormat.java
index 77ac9154d7..e037b83f98 100644
--- a/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestDataFormat.java
+++ b/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestDataFormat.java
@@ -38,7 +38,7 @@ public abstract class BaseTestDataFormat {
 
     protected static final String POUND_FMT = "\"\u00a3\"#,##0;[Red]\\-\"\u00a3\"#,##0";
 
-    private final ITestDataProvider _testDataProvider;
+    protected final ITestDataProvider _testDataProvider;
 
     protected BaseTestDataFormat(ITestDataProvider testDataProvider) {
         _testDataProvider = testDataProvider;
diff --git a/test-data/spreadsheet/decimal-format.xlsx b/test-data/spreadsheet/decimal-format.xlsx
new file mode 100644
index 0000000000..72484c9c31
Binary files /dev/null and b/test-data/spreadsheet/decimal-format.xlsx differ