org.gradle.integtests.fixtures.logging.comparison.ExhaustiveLinesSearcher Maven / Gradle / Ivy
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/*
* Copyright 2022 the original author or authors.
*
* 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.gradle.integtests.fixtures.logging.comparison;
import org.apache.commons.lang3.StringUtils;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
public class ExhaustiveLinesSearcher {
private final boolean useUnifiedDiff;
private ExhaustiveLinesSearcher(boolean useUnifiedDiff) {
this.useUnifiedDiff = useUnifiedDiff;
}
/**
* Uses the git diff algorithm for presenting matches.
*
* Enabling this option will only show a single match, regardless of how many potential matches
* containing the same number of matching lines are found.
*
* @return searcher that uses a unified diff output
*/
public static ExhaustiveLinesSearcher useUnifiedDiff() {
return new ExhaustiveLinesSearcher(true);
}
/**
* Uses the LCS (longest common subsequence) algorithm for presenting matches.
*
* @return searcher that uses a unified diff output
*/
public static ExhaustiveLinesSearcher useLcsDiff() {
return new ExhaustiveLinesSearcher(false);
}
public void assertLinesContainedIn(List expectedLines, List actualLines) throws LineSearchFailures.AbstractLineListComparisonFailure {
assert !expectedLines.isEmpty() : "there must be expected text";
assert !actualLines.isEmpty() : "there must be output text";
if (actualLines.size() < expectedLines.size()) {
LineSearchFailures.insufficientSize(expectedLines, actualLines);
}
if (!findFirstCompleteMatch(expectedLines, actualLines).isPresent()) {
exhaustiveSearch(expectedLines, actualLines, useUnifiedDiff);
}
}
/**
* Quickly attempts to find a complete match of the expected lines in the actual lines.
*
* @return the index of the first matching line, or {@link Optional#empty()} if no match was found
*/
private static Optional findFirstCompleteMatch(List expectedLines, List actualLines) {
for (int actualIdx = 0; actualIdx < actualLines.size(); actualIdx++) {
if (isMatchingIndex(expectedLines, actualLines, actualIdx)) {
return Optional.of(actualIdx);
}
}
return Optional.empty();
}
/**
* Checks whether the given actual line matches the expected line at the given actual index.
*
* @return {@code true} if the actual index is a valid potential match position for the given number of expected lines,
* and the actual lines matches the corresponding expected lines beginning at that index
*/
private static boolean isMatchingIndex(List expectedLines, List actualLines, int actualMatchStartIdx) {
for (int expectedIdx = 0; expectedIdx < expectedLines.size(); expectedIdx++) {
int actualIdx = actualMatchStartIdx + expectedIdx;
if (actualIdx >= actualLines.size() || !Objects.equals(expectedLines.get(expectedIdx), actualLines.get(actualIdx))) {
return false;
}
}
return true;
}
/**
* Finds all the lines in the actual line that match any line in the expected list.
*
* @return a map of expected line index to a list of all actual line indices that match the expected line
*/
private static Map> findMatchingLines(List expectedLines, List actualLines) {
Map> result = new HashMap<>(expectedLines.size());
for (int expectedIdx = 0; expectedIdx < expectedLines.size(); expectedIdx++) {
String expectedLine = expectedLines.get(expectedIdx);
for (int actualIdx = 0; actualIdx < actualLines.size(); actualIdx++) {
String actualLine = actualLines.get(actualIdx);
if (Objects.equals(expectedLine, actualLine) && !StringUtils.isEmpty(expectedLine)) {
result.computeIfAbsent(expectedIdx, matches -> new ArrayList<>()).add(actualIdx);
}
}
}
return result;
}
private static void exhaustiveSearch(List expectedLines, List actualLines, boolean useUnifiedDiff) {
Map> matchingLines = findMatchingLines(expectedLines, actualLines);
Set potentialMatches = convertMatchingLines(expectedLines, actualLines, matchingLines);
if (matchingLines.isEmpty()) {
LineSearchFailures.noMatchingLines(expectedLines, actualLines);
} else {
filterLessLikelyMatches(potentialMatches);
LineSearchFailures.potentialMatchesExist(expectedLines, actualLines, potentialMatches, useUnifiedDiff);
}
}
private static void filterLessLikelyMatches(Set potentialMatches) {
final long highestNumMatches = potentialMatches.stream().map(PotentialMatch::getNumMatches).max(Long::compareTo).orElse(0L);
potentialMatches.removeIf(pm -> pm.getNumMatches() < highestNumMatches);
}
private static Set convertMatchingLines(List expectedLines, List actualLines, Map> matchingLines) {
Set potentialMatches = new HashSet<>(matchingLines.size());
for (Map.Entry> entry : matchingLines.entrySet()) {
int expectedIdx = entry.getKey();
for (int actualIdx : entry.getValue()) {
int matchBeginsActualIdx = actualIdx - expectedIdx;
if (PotentialMatch.isPossibleMatchIndex(expectedLines, actualLines, matchBeginsActualIdx)) {
potentialMatches.add(new PotentialMatch(expectedLines, actualLines, matchBeginsActualIdx));
}
}
}
return potentialMatches;
}
}