/**
* Copyright 2010 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.waveprotocol.wave.client.paging;
import junit.framework.TestCase;
import org.waveprotocol.wave.client.paging.Traverser.Point;
import org.waveprotocol.wave.client.paging.Traverser.SimplePoint;
/**
* Tests for {@link Traverser} based on random tree structures and locations.
*
*/
public final class RandomizedTraverserTest extends TestCase {
/** Size of the block tree being tested. */
private int size;
/** Root of tree. */
private Block root;
/**
* Builds the random tree.
*
* @param seed seed for randomizer
* @param size number of blocks to build in the tree
*/
private void setUp(int seed, int size) {
this.size = size;
this.root = RandomTreeBuilder.create().withSeed(seed).withZeroBlockProbability(0.3).build(size);
}
/**
* Runs tests for the four locating methods in {@link Traverser}.
*/
private void doTest() {
// Test an even distribution of 2.size + 2 points over the range:
// [start - E, end + E]
double start = root.getStart() - 20;
double end = root.getEnd() + 20;
int count = size * 2 + 2;
testStartWithin(start, end, count);
testEndWithin(start, end, count);
testStartAfter(start, end, count);
testEndBefore(start, end, count);
}
/**
* For an even distribution of {@code count} positions over the range {@code
* [start, end]}, tests {@link Traverser#locateStartWithin(Block, double)}
* against a trivial brute-force implementation.
*/
private void testStartWithin(double start, double end, double count) {
for (int i = 0; i < count; i++) {
double position = start + i * (end - start) / (count - 1);
Point expected = locateStartWithin(root, position);
Point actual = Traverser.locateStartWithin(root, position);
assertEquals(expected, actual);
}
}
/**
* For an even distribution of {@code count} positions over the range {@code
* [start, end]}, tests {@link Traverser#locateEndWithin(Block, double)}
* against a trivial brute-force implementation.
*/
private void testEndWithin(double start, double end, int count) {
for (int i = 0; i < count; i++) {
double position = start + i * (end - start) / (count - 1);
Point expected = locateEndWithin(root, position);
Point actual = Traverser.locateEndWithin(root, position);
assertEquals(expected, actual);
}
}
/**
* For the cross product of even distributions of {@code count} positions and
* {@code count} points over the range {@code [start, end]}, tests
* {@link Traverser#locateStartAfter(Point, double)} against a trivial
* brute-force implementation.
*/
private void testStartAfter(double start, double end, int count) {
for (int i = 0; i < count; i++) {
double position = start + i * (end - start) / (count - 1);
Point reference = locateEndWithin(root, position);
if (reference != null) {
testStartAfter(reference, start, end, count);
}
}
}
/**
* For the cross product of even distributions of {@code count} positions and
* {@code count} points over the range {@code [start, end]}, tests
* {@link Traverser#locateEndBefore(Point, double)} against a trivial
* brute-force implementation.
*/
private void testEndBefore(double start, double end, int count) {
for (int i = 0; i < count; i++) {
double position = start + i * (end - start) / (count - 1);
Point reference = locateStartWithin(root, position);
if (reference != null) {
testEndBefore(reference, start, end, count);
}
}
}
/**
* For an even distribution of {@code count} points over the range {@code
* [start, end]}, tests {@link Traverser#locateStartAfter(Point, double)}
* against a trivial brute-force implementation.
*/
private void testStartAfter(Point ref, double start, double end, double count) {
for (int i = 0; i < count; i++) {
double position = start + i * (end - start) / (count - 1);
// expected = null means exception expected.
Point expected = ref.absoluteLocation() < position ? locateStartWithin(root, position) : null;
Point actual;
try {
actual = Traverser.locateStartAfter(ref, position);
assertNotNull(actual);
} catch (IllegalArgumentException e) {
actual = null;
}
assertEquals(expected, actual);
}
}
/**
* For an even distribution of {@code count} points over the range {@code
* [start, end]}, tests {@link Traverser#locateEndBefore(Point, double)}
* against a trivial brute-force implementation.
*/
private void testEndBefore(Point ref, double start, double end, double count) {
for (int i = 0; i < count; i++) {
double position = start + i * (end - start) / (count - 1);
// expected = null means exception expected.
Point expected = ref.absoluteLocation() > position ? locateEndWithin(root, position) : null;
Point actual;
try {
actual = Traverser.locateEndBefore(ref, position);
assertNotNull(actual);
} catch (IllegalArgumentException e) {
actual = null;
}
assertEquals(expected, actual);
}
}
/** @return the rightmost point in a tree that is strictly before a position. */
private Point locateStartWithin(Block block, double position) {
return locateStartBefore(SimplePoint.startOf(block), position);
}
/** @return the leftmost point in a tree that is strictly after a position. */
private Point locateEndWithin(Block block, double position) {
return locateEndAfter(SimplePoint.endOf(block), position);
}
/**
* @return the rightmost point in a tree, at or after a reference, that is
* strictly before a position.
*/
private Point locateStartBefore(Point ref, double position) {
SimpleMoveablePoint point = SimpleMoveablePoint.at(ref);
if (point.absoluteLocation() >= position) {
return null;
} else {
while (point.absoluteLocation() < position) {
if (point.hasNext()) {
point.next();
} else {
return point;
}
}
point.previous();
return point;
}
}
/**
* @return the leftmost point in a tree, at or before a reference, that is
* strictly after a position.
*/
private Point locateEndAfter(Point ref, double position) {
SimpleMoveablePoint point = SimpleMoveablePoint.at(ref);
if (point.absoluteLocation() <= position) {
return null;
} else {
while (point.absoluteLocation() > position) {
if (point.hasPrevious()) {
point.previous();
} else {
return point;
}
}
// Backtrack one.
point.next();
return point;
}
}
public void testRandom1() {
setUp(1, 10);
doTest();
}
public void testRandom2() {
setUp(2, 20);
doTest();
}
public void testRandom3() {
setUp(3, 1);
doTest();
}
public void testRandom4() {
setUp(4, 10);
doTest();
}
public void testRandom5() {
setUp(5, 30);
doTest();
}
}