@Test
  public void testStringScalarCompareStringColProjection() throws HiveException {
    VectorizedRowBatch batch = makeStringBatch();
    VectorExpression expr;

    expr = new StringScalarEqualStringGroupColumn(red2, 0, 2);
    expr.evaluate(batch);
    Assert.assertEquals(3, batch.size);
    LongColumnVector outVector = (LongColumnVector) batch.cols[2];
    Assert.assertEquals(1, outVector.vector[0]);
    Assert.assertEquals(0, outVector.vector[1]);
    Assert.assertEquals(0, outVector.vector[2]);

    batch = makeStringBatch();
    expr = new StringScalarEqualStringGroupColumn(green, 0, 2);
    expr.evaluate(batch);
    Assert.assertEquals(3, batch.size);
    outVector = (LongColumnVector) batch.cols[2];
    Assert.assertEquals(0, outVector.vector[0]);
    Assert.assertEquals(1, outVector.vector[1]);
    Assert.assertEquals(0, outVector.vector[2]);
  }
Test vectorized expression and filter evaluation for strings.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/expressions/TestVectorStringExpressions.java