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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.searchlib.aggregation.hll;
import com.yahoo.vespa.objects.BufferSerializer;
import org.junit.Test;
import java.util.Arrays;
import java.util.List;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
public class NormalSketchTest {
@Test
public void requireThatSerializationIsCorrectForCompressibleData() {
testSerializationForPrecision(16);
}
@Test
public void requireThatSerializationIsCorrectForIncompressibleData() {
// A sketch of precision 1 contains only two elements and will therefore not be compressible.
testSerializationForPrecision(1);
}
private static void testSerializationForPrecision(int precision) {
NormalSketch from = new NormalSketch(precision); // precision p => 2^p bytes
for (int i = 0; i < from.size(); i++) {
from.data()[i] = (byte) i;
}
NormalSketch to = new NormalSketch(precision);
BufferSerializer buffer = new BufferSerializer();
from.serialize(buffer);
buffer.flip();
to.deserialize(buffer);
assertEquals(from, to);
}
@Test
public void requireThatMergeDoesElementWiseMax() {
NormalSketch s1 = new NormalSketch(2);
setSketchValues(s1, 0, 1, 1, 3);
NormalSketch s2 = new NormalSketch(2);
setSketchValues(s2, 2, 1, 1, 0);
s1.merge(s2);
assertBucketEquals(s1, 0, 2);
assertBucketEquals(s1, 1, 1);
assertBucketEquals(s1, 2, 1);
assertBucketEquals(s1, 3, 3);
}
@Test(expected = IllegalArgumentException.class)
public void requireThatMergingFailsForSketchesOfDifferentSize() {
NormalSketch s1 = new NormalSketch(2);
NormalSketch s2 = new NormalSketch(3);
s1.merge(s2);
}
@Test
public void requireThatEqualsIsCorrect() {
NormalSketch s1 = new NormalSketch(1);
setSketchValues(s1, 42, 127);
NormalSketch s2 = new NormalSketch(1);
setSketchValues(s2, 42, 127);
assertEquals(s1, s2);
}
@Test
public void requireThatSketchBucketsAreCorrectForSingleValues() {
testSingleValueAggregation(0, 0, 23);
testSingleValueAggregation(1, 1, 23);
testSingleValueAggregation(-1, 1023, 1);
testSingleValueAggregation(Integer.MAX_VALUE, 1023, 2);
testSingleValueAggregation(Integer.MIN_VALUE, 0, 1);
testSingleValueAggregation(42, 42, 23);
testSingleValueAggregation(0b00000011_00000000_00000000_11000011, 0b11000011, 7);
}
private static void testSingleValueAggregation(int hashValue, int bucketIndex, int expectedValue) {
NormalSketch sketch = new NormalSketch(10);
sketch.aggregate(hashValue);
assertBucketEquals(sketch, bucketIndex, expectedValue);
for (int i = 0; i < sketch.size(); i++) {
if (i == bucketIndex) {
continue;
}
assertBucketEquals(sketch, i, 0);
}
}
@Test
public void requireThatSketchBucketsAreCorrectForMultipleValues() {
NormalSketch sketch = new NormalSketch(10);
// Aggregate multiple values
sketch.aggregate(Arrays.asList(0, 1, 2, 3, 4, 5, 6, 7, 8, 9));
for (int i = 0; i < 10; i++) {
assertBucketEquals(sketch, i, 23);
}
// Check that the other values are zero.
for (int i = 10; i < 1024; i++) {
assertBucketEquals(sketch, i, 0);
}
}
private static void assertBucketEquals(NormalSketch sketch, int index, int expectedValue) {
assertEquals(expectedValue, sketch.data()[index]);
}
private static void setSketchValues(NormalSketch sketch, Integer... values) {
for (int i = 0; i < values.length; i++) {
sketch.data()[i] = values[i].byteValue();
}
}
}
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