@Test
  public void testDecimalScalarSubtractDecimalColumn() throws HiveException {
    VectorizedRowBatch b = getVectorizedRowBatch3DecimalCols();
    HiveDecimal d = HiveDecimal.create(1);
    VectorExpression expr = new DecimalScalarSubtractDecimalColumn(d, 0, 2);

    // test without nulls
    expr.evaluate(b);
    DecimalColumnVector r = (DecimalColumnVector) b.cols[2];
    assertTrue(r.vector[0].getHiveDecimal().equals(HiveDecimal.create("-0.20")));
    assertTrue(r.vector[1].getHiveDecimal().equals(HiveDecimal.create("4.30")));
    assertTrue(r.vector[2].getHiveDecimal().equals(HiveDecimal.create("1")));

    // test that overflow produces null
    b = getVectorizedRowBatch3DecimalCols();
    DecimalColumnVector in = (DecimalColumnVector) b.cols[0];
    in.vector[0].set(HiveDecimal.create("-9999999999999999.99")); // set to min possible value
    expr.evaluate(b);
    r = (DecimalColumnVector) b.cols[2];
    assertFalse(r.noNulls);
    assertTrue(r.isNull[0]);
  }
Unit tests for vectorized arithmetic expressions.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/expressions/TestVectorArithmeticExpressions.java