public TestFuncPtg(String name) 
{
        super( name );
}

 public static  void main(String[] args) 
{
        junit.textui.TestRunner.run( TestFuncPtg.class );
}

 public  void testLeftOvers() 
{
        byte[] fakeData = new byte[4];
        fakeData[0] = (byte) 0x41;
        fakeData[1] = (byte) 0x20;  //function index
        fakeData[2] = (byte) 0;
        fakeData[3] = (byte) 8;
        FuncPtg ptg = new FuncPtg( fakeData, 0 );
        assertEquals( "Len formula index is not 32(20H)", (int) 0x20, ptg.getFunctionIndex() );
        assertEquals( "Number of operands in the len formula", 1, ptg.getNumberOfOperands() );
        assertEquals( "Function Name", "LEN", ptg.getName() );
        assertEquals( "Ptg Size", 3, ptg.getSize() );
        //assertEquals("first leftover byte is not 0", (byte)0, ptg.leftOvers[0]);
        //assertEquals("second leftover byte is not 8", (byte)8, ptg.leftOvers[1]);
}

Make sure the left overs are re-serialized on excel file reads to avoid the "Warning: Data may have been lost" prompt in excel.

This ptg represents a LEN function extracted from excel