2 * Copyright (c) 2016 Red Hat, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.mdsal.binding.testutils;
10 import com.github.difflib.DiffUtils;
11 import com.github.difflib.UnifiedDiffUtils;
12 import com.github.difflib.algorithm.DiffException;
13 import com.github.difflib.patch.Patch;
14 import com.google.common.base.Joiner;
15 import com.google.common.base.Splitter;
16 import java.util.List;
19 * Utility to create diff of text.
21 * @author Michael Vorburger
23 // package-local: no need to expose this, consider it an implementation detail; public API is the AssertDataObjects
24 final class DiffUtil {
26 // Configuration which we could tune as we use this more
27 private static final int MAX_DIFFS = 1;
28 // number of lines of context output around each difference
29 private static final int CONTEXT_LINES = 3;
31 private static final Splitter SPLITTER = Splitter.on(System.getProperty("line.separator"));
32 private static final Joiner JOINER = Joiner.on(System.getProperty("line.separator"));
34 public static String diff(String expectedText, String actualText) throws DiffException {
35 List<String> originalLines = SPLITTER.splitToList(expectedText);
36 List<String> revisedLines = SPLITTER.splitToList(actualText);
37 Patch<String> patch = DiffUtils.diff(originalLines, revisedLines);
39 UnifiedDiffUtils.generateUnifiedDiff("expected", "actual", originalLines, patch, CONTEXT_LINES);
42 int deltas = patch.getDeltas().size();
43 if (deltas > MAX_DIFFS) {
44 header = String.format("(Too many differences (%d); only showing first %d)%n", deltas, MAX_DIFFS);
45 diff = diff.subList(0, MAX_DIFFS);
47 return header + JOINER.join(diff);