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/*
* Copyright (C) 2010, Google Inc. and others
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0 which is available at
* https://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.eclipse.jgit.diff;
import static org.junit.Assert.assertEquals;
import org.junit.Test;
public class HistogramDiffTest extends AbstractDiffTestCase {
@Override
protected HistogramDiff algorithm() {
HistogramDiff hd = new HistogramDiff();
hd.setFallbackAlgorithm(null);
return hd;
}
@Test
public void testEdit_NoUniqueMiddleSide_FlipBlocks() {
EditList r = diff(t("aRRSSz"), t("aSSRRz"));
assertEquals(2, r.size());
assertEquals(new Edit(1, 3, 1, 1), r.get(0)); // DELETE "RR"
assertEquals(new Edit(5, 5, 3, 5), r.get(1)); // INSERT "RR
}
@Test
public void testEdit_NoUniqueMiddleSide_Insert2() {
EditList r = diff(t("aRSz"), t("aRRSSz"));
assertEquals(1, r.size());
assertEquals(new Edit(2, 2, 2, 4), r.get(0));
}
@Test
public void testEdit_NoUniqueMiddleSide_FlipAndExpand() {
EditList r = diff(t("aRSz"), t("aSSRRz"));
assertEquals(2, r.size());
assertEquals(new Edit(1, 2, 1, 1), r.get(0)); // DELETE "R"
assertEquals(new Edit(3, 3, 2, 5), r.get(1)); // INSERT "SRR"
}
@Test
public void testEdit_LcsContainsUnique() {
EditList r = diff(t("nqnjrnjsnm"), t("AnqnjrnjsnjTnmZ"));
assertEquals(new Edit(0, 0, 0, 1), r.get(0)); // INSERT "A";
assertEquals(new Edit(9, 9, 10, 13), r.get(1)); // INSERT "jTn";
assertEquals(new Edit(10, 10, 14, 15), r.get(2)); // INSERT "Z";
assertEquals(3, r.size());
}
@Test
public void testExceedsChainLength_DuringScanOfA() {
HistogramDiff hd = new HistogramDiff();
hd.setFallbackAlgorithm(null);
hd.setMaxChainLength(3);
SequenceComparator<RawText> cmp = new SequenceComparator<>() {
@Override
public boolean equals(RawText a, int ai, RawText b, int bi) {
return RawTextComparator.DEFAULT.equals(a, ai, b, bi);
}
@Override
public int hash(RawText a, int ai) {
return 1;
}
};
EditList r = hd.diff(cmp, t("RabS"), t("QabT"));
assertEquals(1, r.size());
assertEquals(new Edit(0, 4, 0, 4), r.get(0));
}
@Test
public void testExceedsChainLength_DuringScanOfB() {
HistogramDiff hd = new HistogramDiff();
hd.setFallbackAlgorithm(null);
hd.setMaxChainLength(1);
EditList r = hd.diff(RawTextComparator.DEFAULT, t("RaaS"), t("QaaT"));
assertEquals(1, r.size());
assertEquals(new Edit(0, 4, 0, 4), r.get(0));
}
@Test
public void testFallbackToMyersDiff() {
HistogramDiff hd = new HistogramDiff();
hd.setMaxChainLength(4);
RawTextComparator cmp = RawTextComparator.DEFAULT;
RawText ac = t("bbbbb");
RawText bc = t("AbCbDbEFbZ");
EditList r;
// Without fallback our results are limited due to collisions.
hd.setFallbackAlgorithm(null);
r = hd.diff(cmp, ac, bc);
assertEquals(1, r.size());
// Results go up when we add a fallback for the high collision regions.
hd.setFallbackAlgorithm(MyersDiff.INSTANCE);
r = hd.diff(cmp, ac, bc);
assertEquals(5, r.size());
}
}
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