private VectorizedRowBatch getBatchDecimalLong() {
    VectorizedRowBatch b = new VectorizedRowBatch(2);
    DecimalColumnVector dv;
    short scale = 2;
    b.cols[0] = dv = new DecimalColumnVector(18, scale);
    b.cols[1] = new LongColumnVector();

    b.size = 3;

    dv.vector[0].set(HiveDecimal.create("1.1"));
    dv.vector[1].set(HiveDecimal.create("-2.2"));
    dv.vector[2].set(HiveDecimal.create("9999999999999999.00"));

    return b;
  }
Just spot check the basic case because code path is the same as
for cast of decimal to long due to inheritance.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/expressions/TestVectorTypeCasts.java