001package org.junit.experimental.max;
002
003import java.io.File;
004import java.io.FileInputStream;
005import java.io.FileOutputStream;
006import java.io.IOException;
007import java.io.ObjectInputStream;
008import java.io.ObjectOutputStream;
009import java.io.Serializable;
010import java.util.Comparator;
011import java.util.HashMap;
012import java.util.Map;
013
014import org.junit.runner.Description;
015import org.junit.runner.Result;
016import org.junit.runner.notification.Failure;
017import org.junit.runner.notification.RunListener;
018
019/**
020 * Stores a subset of the history of each test:
021 * <ul>
022 * <li>Last failure timestamp
023 * <li>Duration of last execution
024 * </ul>
025 */
026public class MaxHistory implements Serializable {
027    private static final long serialVersionUID = 1L;
028
029    /**
030     * Loads a {@link MaxHistory} from {@code file}, or generates a new one that
031     * will be saved to {@code file}.
032     */
033    public static MaxHistory forFolder(File file) {
034        if (file.exists()) {
035            try {
036                return readHistory(file);
037            } catch (CouldNotReadCoreException e) {
038                e.printStackTrace();
039                file.delete();
040            }
041        }
042        return new MaxHistory(file);
043    }
044
045    private static MaxHistory readHistory(File storedResults)
046            throws CouldNotReadCoreException {
047        try {
048            FileInputStream file = new FileInputStream(storedResults);
049            try {
050                ObjectInputStream stream = new ObjectInputStream(file);
051                try {
052                    return (MaxHistory) stream.readObject();
053                } finally {
054                    stream.close();
055                }
056            } finally {
057                file.close();
058            }
059        } catch (Exception e) {
060            throw new CouldNotReadCoreException(e);
061        }
062    }
063
064    /*
065     * We have to use the f prefix until the next major release to ensure
066     * serialization compatibility. 
067     * See https://github.com/junit-team/junit/issues/976
068     */
069    private final Map<String, Long> fDurations = new HashMap<String, Long>();
070    private final Map<String, Long> fFailureTimestamps = new HashMap<String, Long>();
071    private final File fHistoryStore;
072
073    private MaxHistory(File storedResults) {
074        fHistoryStore = storedResults;
075    }
076
077    private void save() throws IOException {
078        ObjectOutputStream stream = new ObjectOutputStream(new FileOutputStream(
079                fHistoryStore));
080        stream.writeObject(this);
081        stream.close();
082    }
083
084    Long getFailureTimestamp(Description key) {
085        return fFailureTimestamps.get(key.toString());
086    }
087
088    void putTestFailureTimestamp(Description key, long end) {
089        fFailureTimestamps.put(key.toString(), end);
090    }
091
092    boolean isNewTest(Description key) {
093        return !fDurations.containsKey(key.toString());
094    }
095
096    Long getTestDuration(Description key) {
097        return fDurations.get(key.toString());
098    }
099
100    void putTestDuration(Description description, long duration) {
101        fDurations.put(description.toString(), duration);
102    }
103
104    private final class RememberingListener extends RunListener {
105        private long overallStart = System.currentTimeMillis();
106
107        private Map<Description, Long> starts = new HashMap<Description, Long>();
108
109        @Override
110        public void testStarted(Description description) throws Exception {
111            starts.put(description, System.nanoTime()); // Get most accurate
112            // possible time
113        }
114
115        @Override
116        public void testFinished(Description description) throws Exception {
117            long end = System.nanoTime();
118            long start = starts.get(description);
119            putTestDuration(description, end - start);
120        }
121
122        @Override
123        public void testFailure(Failure failure) throws Exception {
124            putTestFailureTimestamp(failure.getDescription(), overallStart);
125        }
126
127        @Override
128        public void testRunFinished(Result result) throws Exception {
129            save();
130        }
131    }
132
133    private class TestComparator implements Comparator<Description> {
134        public int compare(Description o1, Description o2) {
135            // Always prefer new tests
136            if (isNewTest(o1)) {
137                return -1;
138            }
139            if (isNewTest(o2)) {
140                return 1;
141            }
142            // Then most recently failed first
143            int result = getFailure(o2).compareTo(getFailure(o1));
144            return result != 0 ? result
145                    // Then shorter tests first
146                    : getTestDuration(o1).compareTo(getTestDuration(o2));
147        }
148
149        private Long getFailure(Description key) {
150            Long result = getFailureTimestamp(key);
151            if (result == null) {
152                return 0L; // 0 = "never failed (that I know about)"
153            }
154            return result;
155        }
156    }
157
158    /**
159     * @return a listener that will update this history based on the test
160     *         results reported.
161     */
162    public RunListener listener() {
163        return new RememberingListener();
164    }
165
166    /**
167     * @return a comparator that ranks tests based on the JUnit Max sorting
168     *         rules, as described in the {@link MaxCore} class comment.
169     */
170    public Comparator<Description> testComparator() {
171        return new TestComparator();
172    }
173}