@Test(expected=ExceptionFromTest.class)
public void txn_exception_01() {

    Txn.executeWrite(counter, counter::inc) ;
    
    Txn.executeWrite(counter, () -> {
        counter.inc() ;
        assertEquals("In W, value()", 1, counter.value()) ;
        assertEquals("In W, get()",2, counter.get()) ;
        throw new ExceptionFromTest() ;
    }) ;
}