@Test
  // Test string literal to string column comparison
  public void testStringScalarCompareStringCol() throws HiveException {
    VectorizedRowBatch batch = makeStringBatch();
    VectorExpression expr;
    expr = new FilterStringScalarEqualStringGroupColumn(red2, 0);
    expr.evaluate(batch);

    // only red qualifies, and it's in entry 0
    Assert.assertTrue(batch.size == 1);
    Assert.assertTrue(batch.selected[0] == 0);

    batch = makeStringBatch();
    expr = new FilterStringScalarGreaterStringGroupColumn(red2, 0);
    expr.evaluate(batch);

    // only green qualifies, and it's in entry 1
    Assert.assertTrue(batch.size == 1);
    Assert.assertTrue(batch.selected[0] == 1);

    batch = makeStringBatch();
    expr = new FilterStringScalarLessEqualStringGroupColumn(green, 0);
    expr.evaluate(batch);

    // green and red qualify
    Assert.assertTrue(batch.size == 2);
    Assert.assertTrue(batch.selected[0] == 0);
    Assert.assertTrue(batch.selected[1] == 1);
  }
Test vectorized expression and filter evaluation for strings.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/expressions/TestVectorStringExpressions.java