src/test/java/com/yahoo/sketches/pig/frequencies/FrequentStringsSketchToEstimatesTest.java

/*
 * Copyright 2016, Yahoo! Inc.
 * Licensed under the terms of the Apache License 2.0. See LICENSE file at the project root for terms.
 */
package com.yahoo.sketches.pig.frequencies;

import java.util.Iterator;

import org.apache.pig.EvalFunc;
import org.apache.pig.data.DataBag;
import org.apache.pig.data.DataByteArray;
import org.apache.pig.data.DataType;
import org.apache.pig.data.Tuple;
import org.apache.pig.data.TupleFactory;
import org.apache.pig.impl.logicalLayer.schema.Schema;

import org.testng.Assert;
import org.testng.annotations.Test;

import com.yahoo.sketches.ArrayOfStringsSerDe;
import com.yahoo.sketches.frequencies.ItemsSketch;
import com.yahoo.sketches.pig.tuple.PigUtil;

public class FrequentStringsSketchToEstimatesTest {
  @Test
  public void nullInput() throws Exception {
    EvalFunc<DataBag> func = new FrequentStringsSketchToEstimates();
    DataBag bag = func.exec(null);
    Assert.assertNull(bag);
  }

  @Test
  public void emptyInput() throws Exception {
    EvalFunc<DataBag> func = new FrequentStringsSketchToEstimates();
    DataBag bag = func.exec(TupleFactory.getInstance().newTuple());
    Assert.assertNull(bag);
  }

  @Test
  public void emptySketch() throws Exception {
    EvalFunc<DataBag> func = new FrequentStringsSketchToEstimates();
    ItemsSketch<String> sketch = new ItemsSketch<String>(8);
    Tuple inputTuple = PigUtil.objectsToTuple(new DataByteArray(sketch.toByteArray(new ArrayOfStringsSerDe())));
    DataBag bag = func.exec(inputTuple);
    Assert.assertNotNull(bag);
    Assert.assertEquals(bag.size(), 0);
  }

  @Test
  public void exact() throws Exception {
    EvalFunc<DataBag> func = new FrequentStringsSketchToEstimates();
    ItemsSketch<String> sketch = new ItemsSketch<String>(8);
    sketch.update("a");
    sketch.update("a");
    sketch.update("b");
    Tuple inputTuple = PigUtil.objectsToTuple(new DataByteArray(sketch.toByteArray(new ArrayOfStringsSerDe())));
    DataBag bag = func.exec(inputTuple);
    Assert.assertNotNull(bag);
    Assert.assertEquals(bag.size(), 2);

    Iterator<Tuple> it = bag.iterator();
    Tuple tuple1 = it.next();
    Assert.assertEquals(tuple1.size(), 4);
    Assert.assertEquals((String)tuple1.get(0), "a");
    Assert.assertEquals((long)tuple1.get(1), 2L);
    Assert.assertEquals((long)tuple1.get(2), 2L);
    Assert.assertEquals((long)tuple1.get(3), 2L);

    Tuple tuple2 = it.next();
    Assert.assertEquals(tuple2.size(), 4);
    Assert.assertEquals((String)tuple2.get(0), "b");
    Assert.assertEquals((long)tuple2.get(1), 1L);
    Assert.assertEquals((long)tuple2.get(2), 1L);
    Assert.assertEquals((long)tuple2.get(3), 1L);
  }

  @Test
  public void estimation() throws Exception {
    ItemsSketch<String> sketch = new ItemsSketch<String>(8);
    sketch.update("1", 1000);
    sketch.update("2", 500);
    sketch.update("3", 200);
    sketch.update("4", 100);
    sketch.update("5", 50);
    sketch.update("6", 20);
    sketch.update("7", 10);
    sketch.update("8", 5);
    sketch.update("9", 2);
    sketch.update("10");
    Tuple inputTuple = PigUtil.objectsToTuple(new DataByteArray(sketch.toByteArray(new ArrayOfStringsSerDe())));

    EvalFunc<DataBag> func1 = new FrequentStringsSketchToEstimates("NO_FALSE_POSITIVES");
    DataBag bag1 = func1.exec(inputTuple);
    Assert.assertNotNull(bag1);
    Assert.assertTrue(bag1.size() < 10);

    EvalFunc<DataBag> func2 = new FrequentStringsSketchToEstimates("NO_FALSE_NEGATIVES");
    DataBag bag2 = func2.exec(inputTuple);
    Assert.assertNotNull(bag2);
    Assert.assertTrue(bag2.size() < 10);

    Assert.assertTrue(bag1.size() < bag2.size());
  }

  @Test
  public void schema() throws Exception {
    EvalFunc<DataBag> func = new FrequentStringsSketchToEstimates();
    Schema schema = func.outputSchema(null);
    Assert.assertNotNull(schema);
    Assert.assertEquals(schema.size(), 1);
    Assert.assertEquals(schema.getField(0).type, DataType.BAG);
    Assert.assertEquals(schema.getField(0).schema.size(), 1);
    Assert.assertEquals(schema.getField(0).schema.getField(0).type, DataType.TUPLE);
    Assert.assertEquals(schema.getField(0).schema.getField(0).schema.size(), 4);
    Assert.assertEquals(schema.getField(0).schema.getField(0).schema.getField(0).type, DataType.CHARARRAY);
    Assert.assertEquals(schema.getField(0).schema.getField(0).schema.getField(1).type, DataType.LONG);
    Assert.assertEquals(schema.getField(0).schema.getField(0).schema.getField(2).type, DataType.LONG);
    Assert.assertEquals(schema.getField(0).schema.getField(0).schema.getField(3).type, DataType.LONG);
  }
}