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.google.common.base.Joiner;
11 import com.google.common.base.Splitter;
12 import difflib.DiffUtils;
14 import java.util.List;
17 * Utility to create diff of text.
19 * @author Michael Vorburger
21 // package-local: no need to expose this, consider it an implementation detail; public API is the AssertDataObjects
22 final class DiffUtil {
24 // Configuration which we could tune as we use this more
25 private static final int MAX_DIFFS = 1;
26 private static final int CONTEXT_LINES = 3; // number of lines of context output around each difference
28 private static final Splitter SPLITTER = Splitter.on(System.getProperty("line.separator"));
29 private static final Joiner JOINER = Joiner.on(System.getProperty("line.separator"));
31 public static String diff(String expectedText, String actualText) {
32 List<String> originalLines = SPLITTER.splitToList(expectedText);
33 List<String> revisedLines = SPLITTER.splitToList(actualText);
34 Patch<String> patch = DiffUtils.diff(originalLines, revisedLines);
35 List<String> diff = DiffUtils.generateUnifiedDiff("expected", "actual", originalLines, patch, CONTEXT_LINES);
38 int deltas = patch.getDeltas().size();
39 if (deltas > MAX_DIFFS) {
40 header = String.format("(Too many differences (%d); only showing first %d)%n", deltas, MAX_DIFFS);
41 diff = diff.subList(0, MAX_DIFFS);
43 return header + JOINER.join(diff);
46 private DiffUtil() { }