Merge "Fix dicttool build" am: a92d0f9262

am: 438a303732

Change-Id: If8b5ba833fa6872fcaeb43dbd7b0b0c9a5c65986

4 files changed, 1169 insertions, 0 deletions

diff --git a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderEncoderTests.java b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderEncoderTests.java
new file mode 100644
index 000000000..39da9fcd6
--- /dev/null
+++ b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderEncoderTests.java
@@ -0,0 +1,677 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * 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 com.android.inputmethod.latin.makedict;
+
+import android.test.AndroidTestCase;
+import android.test.suitebuilder.annotation.LargeTest;
+import android.util.Log;
+import android.util.Pair;
+import android.util.SparseArray;
+
+import com.android.inputmethod.latin.BinaryDictionary;
+import com.android.inputmethod.latin.common.CodePointUtils;
+import com.android.inputmethod.latin.makedict.BinaryDictDecoderUtils.CharEncoding;
+import com.android.inputmethod.latin.makedict.BinaryDictDecoderUtils.DictBuffer;
+import com.android.inputmethod.latin.makedict.FormatSpec.FormatOptions;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNode;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
+import com.android.inputmethod.latin.utils.BinaryDictionaryUtils;
+import com.android.inputmethod.latin.utils.ByteArrayDictBuffer;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map.Entry;
+import java.util.Random;
+import java.util.Set;
+import java.util.TreeMap;
+
+/**
+ * Unit tests for BinaryDictDecoderUtils and BinaryDictEncoderUtils.
+ */
+@LargeTest
+public class BinaryDictDecoderEncoderTests extends AndroidTestCase {
+    private static final String TAG = BinaryDictDecoderEncoderTests.class.getSimpleName();
+    private static final int DEFAULT_MAX_UNIGRAMS = 300;
+    private static final int DEFAULT_CODE_POINT_SET_SIZE = 50;
+    private static final int LARGE_CODE_POINT_SET_SIZE = 300;
+    private static final int UNIGRAM_FREQ = 10;
+    private static final int BIGRAM_FREQ = 50;
+    private static final int TOLERANCE_OF_BIGRAM_FREQ = 5;
+
+    private static final ArrayList<String> sWords = new ArrayList<>();
+    private static final ArrayList<String> sWordsWithVariousCodePoints = new ArrayList<>();
+    private static final SparseArray<List<Integer>> sEmptyBigrams = new SparseArray<>();
+    private static final SparseArray<List<Integer>> sStarBigrams = new SparseArray<>();
+    private static final SparseArray<List<Integer>> sChainBigrams = new SparseArray<>();
+
+    final Random mRandom;
+
+    public BinaryDictDecoderEncoderTests() {
+        this(System.currentTimeMillis(), DEFAULT_MAX_UNIGRAMS);
+    }
+
+    public BinaryDictDecoderEncoderTests(final long seed, final int maxUnigrams) {
+        super();
+        BinaryDictionaryUtils.setCurrentTimeForTest(0);
+        Log.e(TAG, "Testing dictionary: seed is " + seed);
+        mRandom = new Random(seed);
+        sWords.clear();
+        sWordsWithVariousCodePoints.clear();
+        generateWords(maxUnigrams, mRandom);
+
+        for (int i = 0; i < sWords.size(); ++i) {
+            sChainBigrams.put(i, new ArrayList<Integer>());
+            if (i > 0) {
+                sChainBigrams.get(i - 1).add(i);
+            }
+        }
+
+        sStarBigrams.put(0, new ArrayList<Integer>());
+        // MAX - 1 because we added one above already
+        final int maxBigrams = Math.min(sWords.size(), FormatSpec.MAX_BIGRAMS_IN_A_PTNODE - 1);
+        for (int i = 1; i < maxBigrams; ++i) {
+            sStarBigrams.get(0).add(i);
+        }
+    }
+
+    @Override
+    protected void setUp() throws Exception {
+        super.setUp();
+        BinaryDictionaryUtils.setCurrentTimeForTest(0);
+    }
+
+    @Override
+    protected void tearDown() throws Exception {
+        // Quit test mode.
+        BinaryDictionaryUtils.setCurrentTimeForTest(-1);
+        super.tearDown();
+    }
+
+    private static void generateWords(final int number, final Random random) {
+        final int[] codePointSet = CodePointUtils.generateCodePointSet(DEFAULT_CODE_POINT_SET_SIZE,
+                random);
+        final Set<String> wordSet = new HashSet<>();
+        while (wordSet.size() < number) {
+            wordSet.add(CodePointUtils.generateWord(random, codePointSet));
+        }
+        sWords.addAll(wordSet);
+
+        final int[] largeCodePointSet = CodePointUtils.generateCodePointSet(
+                LARGE_CODE_POINT_SET_SIZE, random);
+        wordSet.clear();
+        while (wordSet.size() < number) {
+            wordSet.add(CodePointUtils.generateWord(random, largeCodePointSet));
+        }
+        sWordsWithVariousCodePoints.addAll(wordSet);
+    }
+
+    /**
+     * Adds unigrams to the dictionary.
+     */
+    private static void addUnigrams(final int number, final FusionDictionary dict,
+            final List<String> words) {
+        for (int i = 0; i < number; ++i) {
+            final String word = words.get(i);
+            final ArrayList<WeightedString> shortcuts = new ArrayList<>();
+            dict.add(word, new ProbabilityInfo(UNIGRAM_FREQ), false /* isNotAWord */,
+                    false /* isPossiblyOffensive */);
+        }
+    }
+
+    private static void addBigrams(final FusionDictionary dict,
+            final List<String> words,
+            final SparseArray<List<Integer>> bigrams) {
+        for (int i = 0; i < bigrams.size(); ++i) {
+            final int w1 = bigrams.keyAt(i);
+            for (int w2 : bigrams.valueAt(i)) {
+                dict.setBigram(words.get(w1), words.get(w2), new ProbabilityInfo(BIGRAM_FREQ));
+            }
+        }
+    }
+
+//    The following is useful to dump the dictionary into a textual file, but it can't compile
+//    on-device, so it's commented out.
+//    private void dumpToCombinedFileForDebug(final FusionDictionary dict, final String filename)
+//            throws IOException {
+//        com.android.inputmethod.latin.dicttool.CombinedInputOutput.writeDictionaryCombined(
+//                new java.io.FileWriter(new File(filename)), dict);
+//    }
+
+    private static long timeWritingDictToFile(final File file, final FusionDictionary dict,
+            final FormatSpec.FormatOptions formatOptions) {
+
+        long now = -1, diff = -1;
+
+        try {
+            final DictEncoder dictEncoder = BinaryDictUtils.getDictEncoder(file, formatOptions);
+
+            now = System.currentTimeMillis();
+            // If you need to dump the dict to a textual file, uncomment the line below and the
+            // function above
+            // dumpToCombinedFileForDebug(file, "/tmp/foo");
+            dictEncoder.writeDictionary(dict, formatOptions);
+            diff = System.currentTimeMillis() - now;
+        } catch (IOException e) {
+            Log.e(TAG, "IO exception while writing file", e);
+        } catch (UnsupportedFormatException e) {
+            Log.e(TAG, "UnsupportedFormatException", e);
+        }
+
+        return diff;
+    }
+
+    private static void checkDictionary(final FusionDictionary dict, final List<String> words,
+            final SparseArray<List<Integer>> bigrams) {
+        assertNotNull(dict);
+
+        // check unigram
+        for (final String word : words) {
+            final PtNode ptNode = FusionDictionary.findWordInTree(dict.mRootNodeArray, word);
+            assertNotNull(ptNode);
+        }
+
+        // check bigram
+        for (int i = 0; i < bigrams.size(); ++i) {
+            final int w1 = bigrams.keyAt(i);
+            for (final int w2 : bigrams.valueAt(i)) {
+                final PtNode ptNode = FusionDictionary.findWordInTree(dict.mRootNodeArray,
+                        words.get(w1));
+                assertNotNull(words.get(w1) + "," + words.get(w2), ptNode.getBigram(words.get(w2)));
+            }
+        }
+    }
+
+    private static String outputOptions(final int bufferType,
+            final FormatSpec.FormatOptions formatOptions) {
+        final String result = " : buffer type = "
+                + ((bufferType == BinaryDictUtils.USE_BYTE_BUFFER) ? "byte buffer" : "byte array");
+        return result + " : version = " + formatOptions.mVersion;
+    }
+
+    // Tests for readDictionaryBinary and writeDictionaryBinary
+
+    private static long timeReadingAndCheckDict(final File file, final List<String> words,
+            final SparseArray<List<Integer>> bigrams, final int bufferType) {
+        long now, diff = -1;
+
+        FusionDictionary dict = null;
+        try {
+            final DictDecoder dictDecoder = BinaryDictIOUtils.getDictDecoder(file, 0, file.length(),
+                    bufferType);
+            now = System.currentTimeMillis();
+            dict = dictDecoder.readDictionaryBinary(false /* deleteDictIfBroken */);
+            diff  = System.currentTimeMillis() - now;
+        } catch (IOException e) {
+            Log.e(TAG, "IOException while reading dictionary", e);
+        } catch (UnsupportedFormatException e) {
+            Log.e(TAG, "Unsupported format", e);
+        }
+
+        checkDictionary(dict, words, bigrams);
+        return diff;
+    }
+
+    // Tests for readDictionaryBinary and writeDictionaryBinary
+    private String runReadAndWrite(final List<String> words,
+            final SparseArray<List<Integer>> bigrams,
+            final int bufferType, final FormatSpec.FormatOptions formatOptions,
+            final String message) {
+
+        final String dictName = "runReadAndWrite";
+        final String dictVersion = Long.toString(System.currentTimeMillis());
+        final File file = BinaryDictUtils.getDictFile(dictName, dictVersion, formatOptions,
+                getContext().getCacheDir());
+
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
+                BinaryDictUtils.makeDictionaryOptions(dictName, dictVersion, formatOptions));
+        addUnigrams(words.size(), dict, words);
+        addBigrams(dict, words, bigrams);
+        checkDictionary(dict, words, bigrams);
+
+        final long write = timeWritingDictToFile(file, dict, formatOptions);
+        final long read = timeReadingAndCheckDict(file, words, bigrams, bufferType);
+
+        return "PROF: read=" + read + "ms, write=" + write + "ms :" + message
+                + " : " + outputOptions(bufferType, formatOptions);
+    }
+
+    private void runReadAndWriteTests(final List<String> results, final int bufferType,
+            final FormatSpec.FormatOptions formatOptions) {
+        results.add(runReadAndWrite(sWords, sEmptyBigrams, bufferType,
+                formatOptions, "unigram"));
+        results.add(runReadAndWrite(sWords, sChainBigrams, bufferType,
+                formatOptions, "chain"));
+        results.add(runReadAndWrite(sWords, sStarBigrams, bufferType,
+                formatOptions, "star"));
+        results.add(runReadAndWrite(sWords, sEmptyBigrams, bufferType, formatOptions,
+                "unigram with shortcuts"));
+        results.add(runReadAndWrite(sWords, sChainBigrams, bufferType, formatOptions,
+                "chain with shortcuts"));
+        results.add(runReadAndWrite(sWords, sStarBigrams, bufferType, formatOptions,
+                "star with shortcuts"));
+        results.add(runReadAndWrite(sWordsWithVariousCodePoints, sEmptyBigrams,
+                bufferType, formatOptions,
+                "unigram with various code points"));
+    }
+
+    public void testCharacterTableIsPresent() throws IOException, UnsupportedFormatException {
+        final String[] wordSource = {"words", "used", "for", "testing", "a", "code point", "table"};
+        final List<String> words = Arrays.asList(wordSource);
+        final String correctCodePointTable = "toesdrniawuplgfcb ";
+        final String dictName = "codePointTableTest";
+        final String dictVersion = Long.toString(System.currentTimeMillis());
+        final String codePointTableAttribute = DictionaryHeader.CODE_POINT_TABLE_KEY;
+        final File file = BinaryDictUtils.getDictFile(dictName, dictVersion,
+                BinaryDictUtils.STATIC_OPTIONS, getContext().getCacheDir());
+
+        // Write a test dictionary
+        final DictEncoder dictEncoder = new Ver2DictEncoder(file,
+                Ver2DictEncoder.CODE_POINT_TABLE_ON);
+        final FormatSpec.FormatOptions formatOptions =
+                new FormatSpec.FormatOptions(
+                        FormatSpec.MINIMUM_SUPPORTED_STATIC_VERSION);
+        final FusionDictionary sourcedict = new FusionDictionary(new PtNodeArray(),
+                BinaryDictUtils.makeDictionaryOptions(dictName, dictVersion, formatOptions));
+        addUnigrams(words.size(), sourcedict, words);
+        dictEncoder.writeDictionary(sourcedict, formatOptions);
+
+        // Read the dictionary
+        final DictDecoder dictDecoder = BinaryDictIOUtils.getDictDecoder(file, 0, file.length(),
+                DictDecoder.USE_BYTEARRAY);
+        final DictionaryHeader fileHeader = dictDecoder.readHeader();
+        // Check if codePointTable is present
+        assertTrue("codePointTable is not present",
+                fileHeader.mDictionaryOptions.mAttributes.containsKey(codePointTableAttribute));
+        final String codePointTable =
+                fileHeader.mDictionaryOptions.mAttributes.get(codePointTableAttribute);
+        // Check if codePointTable is correct
+        assertEquals("codePointTable is incorrect", codePointTable, correctCodePointTable);
+    }
+
+    // Unit test for CharEncoding.readString and CharEncoding.writeString.
+    public void testCharEncoding() {
+        // the max length of a word in sWords is less than 50.
+        // See generateWords.
+        final byte[] buffer = new byte[50 * 3];
+        final DictBuffer dictBuffer = new ByteArrayDictBuffer(buffer);
+        for (final String word : sWords) {
+            Arrays.fill(buffer, (byte) 0);
+            CharEncoding.writeString(buffer, 0, word, null);
+            dictBuffer.position(0);
+            final String str = CharEncoding.readString(dictBuffer);
+            assertEquals(word, str);
+        }
+    }
+
+    public void testReadAndWriteWithByteBuffer() {
+        final List<String> results = new ArrayList<>();
+
+        runReadAndWriteTests(results, BinaryDictUtils.USE_BYTE_BUFFER,
+                BinaryDictUtils.STATIC_OPTIONS);
+        runReadAndWriteTests(results, BinaryDictUtils.USE_BYTE_BUFFER,
+                BinaryDictUtils.DYNAMIC_OPTIONS_WITHOUT_TIMESTAMP);
+        runReadAndWriteTests(results, BinaryDictUtils.USE_BYTE_BUFFER,
+                BinaryDictUtils.DYNAMIC_OPTIONS_WITH_TIMESTAMP);
+        for (final String result : results) {
+            Log.d(TAG, result);
+        }
+    }
+
+    public void testReadAndWriteWithByteArray() {
+        final List<String> results = new ArrayList<>();
+
+        runReadAndWriteTests(results, BinaryDictUtils.USE_BYTE_ARRAY,
+                BinaryDictUtils.STATIC_OPTIONS);
+        runReadAndWriteTests(results, BinaryDictUtils.USE_BYTE_ARRAY,
+                BinaryDictUtils.DYNAMIC_OPTIONS_WITHOUT_TIMESTAMP);
+        runReadAndWriteTests(results, BinaryDictUtils.USE_BYTE_ARRAY,
+                BinaryDictUtils.DYNAMIC_OPTIONS_WITH_TIMESTAMP);
+
+        for (final String result : results) {
+            Log.d(TAG, result);
+        }
+    }
+
+    // Tests for readUnigramsAndBigramsBinary
+
+    private static void checkWordMap(final List<String> expectedWords,
+            final SparseArray<List<Integer>> expectedBigrams,
+            final TreeMap<Integer, String> resultWords,
+            final TreeMap<Integer, Integer> resultFrequencies,
+            final TreeMap<Integer, ArrayList<PendingAttribute>> resultBigrams,
+            final boolean checkProbability) {
+        // check unigrams
+        final Set<String> actualWordsSet = new HashSet<>(resultWords.values());
+        final Set<String> expectedWordsSet = new HashSet<>(expectedWords);
+        assertEquals(actualWordsSet, expectedWordsSet);
+        if (checkProbability) {
+            for (int freq : resultFrequencies.values()) {
+                assertEquals(freq, UNIGRAM_FREQ);
+            }
+        }
+
+        // check bigrams
+        final HashMap<String, Set<String>> expBigrams = new HashMap<>();
+        for (int i = 0; i < expectedBigrams.size(); ++i) {
+            final String word1 = expectedWords.get(expectedBigrams.keyAt(i));
+            for (int w2 : expectedBigrams.valueAt(i)) {
+                if (expBigrams.get(word1) == null) {
+                    expBigrams.put(word1, new HashSet<String>());
+                }
+                expBigrams.get(word1).add(expectedWords.get(w2));
+            }
+        }
+
+        final HashMap<String, Set<String>> actBigrams = new HashMap<>();
+        for (Entry<Integer, ArrayList<PendingAttribute>> entry : resultBigrams.entrySet()) {
+            final String word1 = resultWords.get(entry.getKey());
+            final int unigramFreq = resultFrequencies.get(entry.getKey());
+            for (PendingAttribute attr : entry.getValue()) {
+                final String word2 = resultWords.get(attr.mAddress);
+                if (actBigrams.get(word1) == null) {
+                    actBigrams.put(word1, new HashSet<String>());
+                }
+                actBigrams.get(word1).add(word2);
+
+                if (checkProbability) {
+                    final int bigramFreq = BinaryDictIOUtils.reconstructBigramFrequency(
+                            unigramFreq, attr.mFrequency);
+                    assertTrue(Math.abs(bigramFreq - BIGRAM_FREQ) < TOLERANCE_OF_BIGRAM_FREQ);
+                }
+            }
+        }
+        assertEquals(actBigrams, expBigrams);
+    }
+
+    private static long timeAndCheckReadUnigramsAndBigramsBinary(final File file,
+            final List<String> words, final SparseArray<List<Integer>> bigrams,
+            final int bufferType, final boolean checkProbability) {
+        final TreeMap<Integer, String> resultWords = new TreeMap<>();
+        final TreeMap<Integer, ArrayList<PendingAttribute>> resultBigrams = new TreeMap<>();
+        final TreeMap<Integer, Integer> resultFreqs = new TreeMap<>();
+
+        long now = -1, diff = -1;
+        try {
+            final DictDecoder dictDecoder = BinaryDictIOUtils.getDictDecoder(file, 0, file.length(),
+                    bufferType);
+            now = System.currentTimeMillis();
+            dictDecoder.readUnigramsAndBigramsBinary(resultWords, resultFreqs, resultBigrams);
+            diff = System.currentTimeMillis() - now;
+        } catch (IOException e) {
+            Log.e(TAG, "IOException", e);
+        } catch (UnsupportedFormatException e) {
+            Log.e(TAG, "UnsupportedFormatException", e);
+        }
+
+        checkWordMap(words, bigrams, resultWords, resultFreqs, resultBigrams, checkProbability);
+        return diff;
+    }
+
+    private String runReadUnigramsAndBigramsBinary(final ArrayList<String> words,
+            final SparseArray<List<Integer>> bigrams, final int bufferType,
+            final FormatSpec.FormatOptions formatOptions, final String message) {
+        final String dictName = "runReadUnigrams";
+        final String dictVersion = Long.toString(System.currentTimeMillis());
+        final File file = BinaryDictUtils.getDictFile(dictName, dictVersion, formatOptions,
+                getContext().getCacheDir());
+
+        // making the dictionary from lists of words.
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
+                BinaryDictUtils.makeDictionaryOptions(dictName, dictVersion, formatOptions));
+        addUnigrams(words.size(), dict, words);
+        addBigrams(dict, words, bigrams);
+
+        timeWritingDictToFile(file, dict, formatOptions);
+
+        // Caveat: Currently, the Java code to read a v4 dictionary doesn't calculate the
+        // probability when there's a timestamp for the entry.
+        // TODO: Abandon the Java code, and implement the v4 dictionary reading code in native.
+        long wordMap = timeAndCheckReadUnigramsAndBigramsBinary(file, words, bigrams, bufferType,
+                !formatOptions.mHasTimestamp /* checkProbability */);
+        long fullReading = timeReadingAndCheckDict(file, words, bigrams,
+                bufferType);
+
+        return "readDictionaryBinary=" + fullReading + ", readUnigramsAndBigramsBinary=" + wordMap
+                + " : " + message + " : " + outputOptions(bufferType, formatOptions);
+    }
+
+    private void runReadUnigramsAndBigramsTests(final ArrayList<String> results,
+            final int bufferType, final FormatSpec.FormatOptions formatOptions) {
+        results.add(runReadUnigramsAndBigramsBinary(sWords, sEmptyBigrams, bufferType,
+                formatOptions, "unigram"));
+        results.add(runReadUnigramsAndBigramsBinary(sWords, sChainBigrams, bufferType,
+                formatOptions, "chain"));
+        results.add(runReadUnigramsAndBigramsBinary(sWords, sStarBigrams, bufferType,
+                formatOptions, "star"));
+    }
+
+    public void testReadUnigramsAndBigramsBinaryWithByteBuffer() {
+        final ArrayList<String> results = new ArrayList<>();
+
+        runReadUnigramsAndBigramsTests(results, BinaryDictUtils.USE_BYTE_BUFFER,
+                BinaryDictUtils.STATIC_OPTIONS);
+
+        for (final String result : results) {
+            Log.d(TAG, result);
+        }
+    }
+
+    public void testReadUnigramsAndBigramsBinaryWithByteArray() {
+        final ArrayList<String> results = new ArrayList<>();
+
+        runReadUnigramsAndBigramsTests(results, BinaryDictUtils.USE_BYTE_ARRAY,
+                BinaryDictUtils.STATIC_OPTIONS);
+
+        for (final String result : results) {
+            Log.d(TAG, result);
+        }
+    }
+
+    // Tests for getTerminalPosition
+    private static String getWordFromBinary(final DictDecoder dictDecoder, final int address) {
+        if (dictDecoder.getPosition() != 0) dictDecoder.setPosition(0);
+
+        DictionaryHeader fileHeader = null;
+        try {
+            fileHeader = dictDecoder.readHeader();
+        } catch (IOException e) {
+            return null;
+        } catch (UnsupportedFormatException e) {
+            return null;
+        }
+        if (fileHeader == null) return null;
+        return BinaryDictDecoderUtils.getWordAtPosition(dictDecoder, fileHeader.mBodyOffset,
+                address).mWord;
+    }
+
+    private static long checkGetTerminalPosition(final DictDecoder dictDecoder, final String word,
+            final boolean contained) {
+        long diff = -1;
+        int position = -1;
+        try {
+            final long now = System.nanoTime();
+            position = dictDecoder.getTerminalPosition(word);
+            diff = System.nanoTime() - now;
+        } catch (IOException e) {
+            Log.e(TAG, "IOException while getTerminalPosition", e);
+        } catch (UnsupportedFormatException e) {
+            Log.e(TAG, "UnsupportedFormatException while getTerminalPosition", e);
+        }
+
+        assertEquals(FormatSpec.NOT_VALID_WORD != position, contained);
+        if (contained) assertEquals(getWordFromBinary(dictDecoder, position), word);
+        return diff;
+    }
+
+    private void runGetTerminalPosition(final ArrayList<String> words,
+            final SparseArray<List<Integer>> bigrams, final int bufferType,
+            final FormatOptions formatOptions, final String message) {
+        final String dictName = "testGetTerminalPosition";
+        final String dictVersion = Long.toString(System.currentTimeMillis());
+        final File file = BinaryDictUtils.getDictFile(dictName, dictVersion, formatOptions,
+                getContext().getCacheDir());
+
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
+                BinaryDictUtils.makeDictionaryOptions(dictName, dictVersion, formatOptions));
+        addUnigrams(sWords.size(), dict, sWords);
+        addBigrams(dict, words, bigrams);
+        timeWritingDictToFile(file, dict, formatOptions);
+
+        final DictDecoder dictDecoder = BinaryDictIOUtils.getDictDecoder(file, 0, file.length(),
+                DictDecoder.USE_BYTEARRAY);
+        try {
+            dictDecoder.openDictBuffer();
+        } catch (IOException e) {
+            Log.e(TAG, "IOException while opening the buffer", e);
+        } catch (UnsupportedFormatException e) {
+            Log.e(TAG, "IOException while opening the buffer", e);
+        }
+        assertTrue("Can't get the buffer", dictDecoder.isDictBufferOpen());
+
+        try {
+            // too long word
+            final String longWord = "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz";
+            assertEquals(FormatSpec.NOT_VALID_WORD, dictDecoder.getTerminalPosition(longWord));
+
+            // null
+            assertEquals(FormatSpec.NOT_VALID_WORD, dictDecoder.getTerminalPosition(null));
+
+            // empty string
+            assertEquals(FormatSpec.NOT_VALID_WORD, dictDecoder.getTerminalPosition(""));
+        } catch (IOException e) {
+        } catch (UnsupportedFormatException e) {
+        }
+
+        // Test a word that is contained within the dictionary.
+        long sum = 0;
+        for (int i = 0; i < sWords.size(); ++i) {
+            final long time = checkGetTerminalPosition(dictDecoder, sWords.get(i), true);
+            sum += time == -1 ? 0 : time;
+        }
+        Log.d(TAG, "per search : " + (((double)sum) / sWords.size() / 1000000) + " : " + message
+                + " : " + outputOptions(bufferType, formatOptions));
+
+        // Test a word that isn't contained within the dictionary.
+        final int[] codePointSet = CodePointUtils.generateCodePointSet(DEFAULT_CODE_POINT_SET_SIZE,
+                mRandom);
+        for (int i = 0; i < 1000; ++i) {
+            final String word = CodePointUtils.generateWord(mRandom, codePointSet);
+            if (sWords.indexOf(word) != -1) continue;
+            checkGetTerminalPosition(dictDecoder, word, false);
+        }
+    }
+
+    private void runGetTerminalPositionTests(final int bufferType,
+            final FormatOptions formatOptions) {
+        runGetTerminalPosition(sWords, sEmptyBigrams, bufferType, formatOptions, "unigram");
+    }
+
+    public void testGetTerminalPosition() {
+        final ArrayList<String> results = new ArrayList<>();
+
+        runGetTerminalPositionTests(BinaryDictUtils.USE_BYTE_ARRAY,
+                BinaryDictUtils.STATIC_OPTIONS);
+        runGetTerminalPositionTests(BinaryDictUtils.USE_BYTE_BUFFER,
+                BinaryDictUtils.STATIC_OPTIONS);
+
+        for (final String result : results) {
+            Log.d(TAG, result);
+        }
+    }
+
+    public void testVer2DictGetWordProperty() {
+        final FormatOptions formatOptions = BinaryDictUtils.STATIC_OPTIONS;
+        final ArrayList<String> words = sWords;
+        final String dictName = "testGetWordProperty";
+        final String dictVersion = Long.toString(System.currentTimeMillis());
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
+                BinaryDictUtils.makeDictionaryOptions(dictName, dictVersion, formatOptions));
+        addUnigrams(words.size(), dict, words);
+        addBigrams(dict, words, sEmptyBigrams);
+        final File file = BinaryDictUtils.getDictFile(dictName, dictVersion, formatOptions,
+                getContext().getCacheDir());
+        file.delete();
+        timeWritingDictToFile(file, dict, formatOptions);
+        final BinaryDictionary binaryDictionary = new BinaryDictionary(file.getAbsolutePath(),
+                0 /* offset */, file.length(), true /* useFullEditDistance */,
+                Locale.ENGLISH, dictName, false /* isUpdatable */);
+        for (final String word : words) {
+            final WordProperty wordProperty = binaryDictionary.getWordProperty(word,
+                    false /* isBeginningOfSentence */);
+            assertEquals(word, wordProperty.mWord);
+            assertEquals(UNIGRAM_FREQ, wordProperty.getProbability());
+        }
+    }
+
+    public void testVer2DictIteration() {
+        final FormatOptions formatOptions = BinaryDictUtils.STATIC_OPTIONS;
+        final ArrayList<String> words = sWords;
+        final SparseArray<List<Integer>> bigrams = sEmptyBigrams;
+        final String dictName = "testGetWordProperty";
+        final String dictVersion = Long.toString(System.currentTimeMillis());
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
+                BinaryDictUtils.makeDictionaryOptions(dictName, dictVersion, formatOptions));
+        addUnigrams(words.size(), dict, words);
+        addBigrams(dict, words, bigrams);
+        final File file = BinaryDictUtils.getDictFile(dictName, dictVersion, formatOptions,
+                getContext().getCacheDir());
+        timeWritingDictToFile(file, dict, formatOptions);
+        Log.d(TAG, file.getAbsolutePath());
+        final BinaryDictionary binaryDictionary = new BinaryDictionary(file.getAbsolutePath(),
+                0 /* offset */, file.length(), true /* useFullEditDistance */,
+                Locale.ENGLISH, dictName, false /* isUpdatable */);
+
+        final HashSet<String> wordSet = new HashSet<>(words);
+        final HashSet<Pair<String, String>> bigramSet = new HashSet<>();
+
+        for (int i = 0; i < words.size(); i++) {
+            final List<Integer> bigramList = bigrams.get(i);
+            if (bigramList != null) {
+                for (final Integer word1Index : bigramList) {
+                    final String word1 = words.get(word1Index);
+                    bigramSet.add(new Pair<>(words.get(i), word1));
+                }
+            }
+        }
+        int token = 0;
+        do {
+            final BinaryDictionary.GetNextWordPropertyResult result =
+                    binaryDictionary.getNextWordProperty(token);
+            final WordProperty wordProperty = result.mWordProperty;
+            final String word0 = wordProperty.mWord;
+            assertEquals(UNIGRAM_FREQ, wordProperty.mProbabilityInfo.mProbability);
+            wordSet.remove(word0);
+            if (wordProperty.mHasNgrams) {
+                for (final WeightedString bigramTarget : wordProperty.getBigrams()) {
+                    final String word1 = bigramTarget.mWord;
+                    final Pair<String, String> bigram = new Pair<>(word0, word1);
+                    assertTrue(bigramSet.contains(bigram));
+                    bigramSet.remove(bigram);
+                }
+            }
+            token = result.mNextToken;
+        } while (token != 0);
+        assertTrue(wordSet.isEmpty());
+        assertTrue(bigramSet.isEmpty());
+    }
+}
diff --git a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictUtils.java b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictUtils.java
new file mode 100644
index 000000000..9c1e4cf84
--- /dev/null
+++ b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictUtils.java
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * 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 com.android.inputmethod.latin.makedict;
+
+import com.android.inputmethod.latin.makedict.FormatSpec.DictionaryOptions;
+import com.android.inputmethod.latin.makedict.FormatSpec.FormatOptions;
+
+import java.io.File;
+import java.util.HashMap;
+
+public class BinaryDictUtils {
+    public static final int USE_BYTE_ARRAY = 1;
+    public static final int USE_BYTE_BUFFER = 2;
+
+    public static final String TEST_DICT_FILE_EXTENSION = ".testDict";
+
+    public static final FormatSpec.FormatOptions STATIC_OPTIONS =
+            new FormatSpec.FormatOptions(FormatSpec.VERSION202);
+    public static final FormatSpec.FormatOptions DYNAMIC_OPTIONS_WITHOUT_TIMESTAMP =
+            new FormatSpec.FormatOptions(FormatSpec.VERSION4, false /* hasTimestamp */);
+    public static final FormatSpec.FormatOptions DYNAMIC_OPTIONS_WITH_TIMESTAMP =
+            new FormatSpec.FormatOptions(FormatSpec.VERSION4, true /* hasTimestamp */);
+
+    public static DictionaryOptions makeDictionaryOptions(final String id, final String version,
+            final FormatSpec.FormatOptions formatOptions) {
+        final DictionaryOptions options = new DictionaryOptions(new HashMap<String, String>());
+        options.mAttributes.put(DictionaryHeader.DICTIONARY_LOCALE_KEY, "en_US");
+        options.mAttributes.put(DictionaryHeader.DICTIONARY_ID_KEY, id);
+        options.mAttributes.put(DictionaryHeader.DICTIONARY_VERSION_KEY, version);
+        if (formatOptions.mHasTimestamp) {
+            options.mAttributes.put(DictionaryHeader.HAS_HISTORICAL_INFO_KEY,
+                    DictionaryHeader.ATTRIBUTE_VALUE_TRUE);
+            options.mAttributes.put(DictionaryHeader.USES_FORGETTING_CURVE_KEY,
+                    DictionaryHeader.ATTRIBUTE_VALUE_TRUE);
+        }
+        return options;
+    }
+
+    public static File getDictFile(final String name, final String version,
+            final FormatOptions formatOptions, final File directory) {
+        if (formatOptions.mVersion == FormatSpec.VERSION2
+                || formatOptions.mVersion == FormatSpec.VERSION201
+                || formatOptions.mVersion == FormatSpec.VERSION202) {
+            return new File(directory, name + "." + version + TEST_DICT_FILE_EXTENSION);
+        } else if (formatOptions.mVersion == FormatSpec.VERSION4) {
+            return new File(directory, name + "." + version);
+        } else {
+            throw new RuntimeException("the format option has a wrong version : "
+                    + formatOptions.mVersion);
+        }
+    }
+
+    public static DictEncoder getDictEncoder(final File file, final FormatOptions formatOptions) {
+        if (formatOptions.mVersion == FormatSpec.VERSION4) {
+            if (!file.isDirectory()) {
+                file.mkdir();
+            }
+            return new Ver4DictEncoder(file);
+        } else if (formatOptions.mVersion == FormatSpec.VERSION202) {
+            return new Ver2DictEncoder(file, Ver2DictEncoder.CODE_POINT_TABLE_OFF);
+        } else {
+            throw new RuntimeException("The format option has a wrong version : "
+                    + formatOptions.mVersion);
+        }
+    }
+}
diff --git a/tests/src/com/android/inputmethod/latin/makedict/Ver2DictEncoder.java b/tests/src/com/android/inputmethod/latin/makedict/Ver2DictEncoder.java
new file mode 100644
index 000000000..c63b972eb
--- /dev/null
+++ b/tests/src/com/android/inputmethod/latin/makedict/Ver2DictEncoder.java
@@ -0,0 +1,279 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * 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 com.android.inputmethod.latin.makedict;
+
+import com.android.inputmethod.annotations.UsedForTesting;
+import com.android.inputmethod.latin.makedict.BinaryDictDecoderUtils.CharEncoding;
+import com.android.inputmethod.latin.makedict.BinaryDictEncoderUtils.CodePointTable;
+import com.android.inputmethod.latin.makedict.FormatSpec.FormatOptions;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNode;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map.Entry;
+
+/**
+ * An implementation of DictEncoder for version 2 binary dictionary.
+ */
+@UsedForTesting
+public class Ver2DictEncoder implements DictEncoder {
+
+    private final File mDictFile;
+    private OutputStream mOutStream;
+    private byte[] mBuffer;
+    private int mPosition;
+    private final int mCodePointTableMode;
+    public static final int CODE_POINT_TABLE_OFF = 0;
+    public static final int CODE_POINT_TABLE_ON = 1;
+
+    @UsedForTesting
+    public Ver2DictEncoder(final File dictFile, final int codePointTableMode) {
+        mDictFile = dictFile;
+        mOutStream = null;
+        mBuffer = null;
+        mCodePointTableMode = codePointTableMode;
+    }
+
+    // This constructor is used only by BinaryDictOffdeviceUtilsTests.
+    // If you want to use this in the production code, you should consider keeping consistency of
+    // the interface of Ver3DictDecoder by using factory.
+    @UsedForTesting
+    public Ver2DictEncoder(final OutputStream outStream) {
+        mDictFile = null;
+        mOutStream = outStream;
+        mCodePointTableMode = CODE_POINT_TABLE_OFF;
+    }
+
+    private void openStream() throws FileNotFoundException {
+        mOutStream = new FileOutputStream(mDictFile);
+    }
+
+    private void close() throws IOException {
+        if (mOutStream != null) {
+            mOutStream.close();
+            mOutStream = null;
+        }
+    }
+
+    // Package for testing
+    static CodePointTable makeCodePointTable(final FusionDictionary dict) {
+        final HashMap<Integer, Integer> codePointOccurrenceCounts = new HashMap<>();
+        for (final WordProperty word : dict) {
+            // Store per code point occurrence
+            final String wordString = word.mWord;
+            for (int i = 0; i < wordString.length(); ++i) {
+                final int codePoint = Character.codePointAt(wordString, i);
+                if (codePointOccurrenceCounts.containsKey(codePoint)) {
+                    codePointOccurrenceCounts.put(codePoint,
+                            codePointOccurrenceCounts.get(codePoint) + 1);
+                } else {
+                    codePointOccurrenceCounts.put(codePoint, 1);
+                }
+            }
+        }
+        final ArrayList<Entry<Integer, Integer>> codePointOccurrenceArray =
+                new ArrayList<>(codePointOccurrenceCounts.entrySet());
+        // Descending order sort by occurrence (value side)
+        Collections.sort(codePointOccurrenceArray, new Comparator<Entry<Integer, Integer>>() {
+            @Override
+            public int compare(final Entry<Integer, Integer> a, final Entry<Integer, Integer> b) {
+                if (a.getValue() != b.getValue()) {
+                    return b.getValue().compareTo(a.getValue());
+                }
+                return b.getKey().compareTo(a.getKey());
+            }
+        });
+        int currentCodePointTableIndex = FormatSpec.MINIMAL_ONE_BYTE_CHARACTER_VALUE;
+        // Temporary map for writing of nodes
+        final HashMap<Integer, Integer> codePointToOneByteCodeMap = new HashMap<>();
+        for (final Entry<Integer, Integer> entry : codePointOccurrenceArray) {
+            // Put a relation from the original code point to the one byte code.
+            codePointToOneByteCodeMap.put(entry.getKey(), currentCodePointTableIndex);
+            if (FormatSpec.MAXIMAL_ONE_BYTE_CHARACTER_VALUE < ++currentCodePointTableIndex) {
+                break;
+            }
+        }
+        // codePointToOneByteCodeMap for writing the trie
+        // codePointOccurrenceArray for writing the header
+        return new CodePointTable(codePointToOneByteCodeMap, codePointOccurrenceArray);
+    }
+
+    @Override
+    public void writeDictionary(final FusionDictionary dict, final FormatOptions formatOptions)
+            throws IOException, UnsupportedFormatException {
+        // We no longer support anything but the latest version of v2.
+        if (formatOptions.mVersion != FormatSpec.VERSION202) {
+            throw new UnsupportedFormatException(
+                    "The given format options has wrong version number : "
+                    + formatOptions.mVersion);
+        }
+
+        if (mOutStream == null) {
+            openStream();
+        }
+
+        // Make code point conversion table ordered by occurrence of code points
+        // Version 201 or later have codePointTable
+        final CodePointTable codePointTable;
+        if (mCodePointTableMode == CODE_POINT_TABLE_OFF || formatOptions.mVersion
+                < FormatSpec.MINIMUM_SUPPORTED_VERSION_OF_CODE_POINT_TABLE) {
+            codePointTable = new CodePointTable();
+        } else {
+            codePointTable = makeCodePointTable(dict);
+        }
+
+        BinaryDictEncoderUtils.writeDictionaryHeader(mOutStream, dict, formatOptions,
+                codePointTable.mCodePointOccurrenceArray);
+
+        // Addresses are limited to 3 bytes, but since addresses can be relative to each node
+        // array, the structure itself is not limited to 16MB. However, if it is over 16MB deciding
+        // the order of the PtNode arrays becomes a quite complicated problem, because though the
+        // dictionary itself does not have a size limit, each node array must still be within 16MB
+        // of all its children and parents. As long as this is ensured, the dictionary file may
+        // grow to any size.
+
+        // Leave the choice of the optimal node order to the flattenTree function.
+        MakedictLog.i("Flattening the tree...");
+        ArrayList<PtNodeArray> flatNodes = BinaryDictEncoderUtils.flattenTree(dict.mRootNodeArray);
+
+        MakedictLog.i("Computing addresses...");
+        BinaryDictEncoderUtils.computeAddresses(dict, flatNodes,
+                codePointTable.mCodePointToOneByteCodeMap);
+        MakedictLog.i("Checking PtNode array...");
+        if (MakedictLog.DBG) BinaryDictEncoderUtils.checkFlatPtNodeArrayList(flatNodes);
+
+        // Create a buffer that matches the final dictionary size.
+        final PtNodeArray lastNodeArray = flatNodes.get(flatNodes.size() - 1);
+        final int bufferSize = lastNodeArray.mCachedAddressAfterUpdate + lastNodeArray.mCachedSize;
+        mBuffer = new byte[bufferSize];
+
+        MakedictLog.i("Writing file...");
+
+        for (PtNodeArray nodeArray : flatNodes) {
+            BinaryDictEncoderUtils.writePlacedPtNodeArray(dict, this, nodeArray,
+                    codePointTable.mCodePointToOneByteCodeMap);
+        }
+        if (MakedictLog.DBG) BinaryDictEncoderUtils.showStatistics(flatNodes);
+        mOutStream.write(mBuffer, 0, mPosition);
+
+        MakedictLog.i("Done");
+        close();
+    }
+
+    @Override
+    public void setPosition(final int position) {
+        if (mBuffer == null || position < 0 || position >= mBuffer.length) return;
+        mPosition = position;
+    }
+
+    @Override
+    public int getPosition() {
+        return mPosition;
+    }
+
+    @Override
+    public void writePtNodeCount(final int ptNodeCount) {
+        final int countSize = BinaryDictIOUtils.getPtNodeCountSize(ptNodeCount);
+        if (countSize != 1 && countSize != 2) {
+            throw new RuntimeException("Strange size from getGroupCountSize : " + countSize);
+        }
+        final int encodedPtNodeCount = (countSize == 2) ?
+                (ptNodeCount | FormatSpec.LARGE_PTNODE_ARRAY_SIZE_FIELD_SIZE_FLAG) : ptNodeCount;
+        mPosition = BinaryDictEncoderUtils.writeUIntToBuffer(mBuffer, mPosition, encodedPtNodeCount,
+                countSize);
+    }
+
+    private void writePtNodeFlags(final PtNode ptNode,
+            final HashMap<Integer, Integer> codePointToOneByteCodeMap) {
+        final int childrenPos = BinaryDictEncoderUtils.getChildrenPosition(ptNode,
+                codePointToOneByteCodeMap);
+        mPosition = BinaryDictEncoderUtils.writeUIntToBuffer(mBuffer, mPosition,
+                BinaryDictEncoderUtils.makePtNodeFlags(ptNode, childrenPos),
+                FormatSpec.PTNODE_FLAGS_SIZE);
+    }
+
+    private void writeCharacters(final int[] codePoints, final boolean hasSeveralChars,
+            final HashMap<Integer, Integer> codePointToOneByteCodeMap) {
+        mPosition = CharEncoding.writeCharArray(codePoints, mBuffer, mPosition,
+                codePointToOneByteCodeMap);
+        if (hasSeveralChars) {
+            mBuffer[mPosition++] = FormatSpec.PTNODE_CHARACTERS_TERMINATOR;
+        }
+    }
+
+    private void writeFrequency(final int frequency) {
+        if (frequency >= 0) {
+            mPosition = BinaryDictEncoderUtils.writeUIntToBuffer(mBuffer, mPosition, frequency,
+                    FormatSpec.PTNODE_FREQUENCY_SIZE);
+        }
+    }
+
+    private void writeChildrenPosition(final PtNode ptNode,
+            final HashMap<Integer, Integer> codePointToOneByteCodeMap) {
+        final int childrenPos = BinaryDictEncoderUtils.getChildrenPosition(ptNode,
+                codePointToOneByteCodeMap);
+        mPosition += BinaryDictEncoderUtils.writeChildrenPosition(mBuffer, mPosition,
+                childrenPos);
+    }
+
+    /**
+     * Write a bigram attributes list to mBuffer.
+     *
+     * @param bigrams the bigram attributes list.
+     * @param dict the dictionary the node array is a part of (for relative offsets).
+     */
+    private void writeBigrams(final ArrayList<WeightedString> bigrams,
+            final FusionDictionary dict) {
+        if (bigrams == null) return;
+
+        final Iterator<WeightedString> bigramIterator = bigrams.iterator();
+        while (bigramIterator.hasNext()) {
+            final WeightedString bigram = bigramIterator.next();
+            final PtNode target =
+                    FusionDictionary.findWordInTree(dict.mRootNodeArray, bigram.mWord);
+            final int addressOfBigram = target.mCachedAddressAfterUpdate;
+            final int unigramFrequencyForThisWord = target.getProbability();
+            final int offset = addressOfBigram
+                    - (mPosition + FormatSpec.PTNODE_ATTRIBUTE_FLAGS_SIZE);
+            final int bigramFlags = BinaryDictEncoderUtils.makeBigramFlags(bigramIterator.hasNext(),
+                    offset, bigram.getProbability(), unigramFrequencyForThisWord, bigram.mWord);
+            mPosition = BinaryDictEncoderUtils.writeUIntToBuffer(mBuffer, mPosition, bigramFlags,
+                    FormatSpec.PTNODE_ATTRIBUTE_FLAGS_SIZE);
+            mPosition += BinaryDictEncoderUtils.writeChildrenPosition(mBuffer, mPosition,
+                    Math.abs(offset));
+        }
+    }
+
+    @Override
+    public void writePtNode(final PtNode ptNode, final FusionDictionary dict,
+            final HashMap<Integer, Integer> codePointToOneByteCodeMap) {
+        writePtNodeFlags(ptNode, codePointToOneByteCodeMap);
+        writeCharacters(ptNode.mChars, ptNode.hasSeveralChars(), codePointToOneByteCodeMap);
+        writeFrequency(ptNode.getProbability());
+        writeChildrenPosition(ptNode, codePointToOneByteCodeMap);
+        writeBigrams(ptNode.mBigrams, dict);
+    }
+}
diff --git a/tests/src/com/android/inputmethod/latin/makedict/Ver4DictEncoder.java b/tests/src/com/android/inputmethod/latin/makedict/Ver4DictEncoder.java
new file mode 100644
index 000000000..6e7b37d54
--- /dev/null
+++ b/tests/src/com/android/inputmethod/latin/makedict/Ver4DictEncoder.java
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * 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 com.android.inputmethod.latin.makedict;
+
+import com.android.inputmethod.annotations.UsedForTesting;
+import com.android.inputmethod.latin.BinaryDictionary;
+import com.android.inputmethod.latin.Dictionary;
+import com.android.inputmethod.latin.NgramContext;
+import com.android.inputmethod.latin.common.LocaleUtils;
+import com.android.inputmethod.latin.makedict.FormatSpec.FormatOptions;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNode;
+import com.android.inputmethod.latin.utils.BinaryDictionaryUtils;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.HashMap;
+
+/**
+ * An implementation of DictEncoder for version 4 binary dictionary.
+ */
+@UsedForTesting
+public class Ver4DictEncoder implements DictEncoder {
+    private final File mDictPlacedDir;
+
+    @UsedForTesting
+    public Ver4DictEncoder(final File dictPlacedDir) {
+        mDictPlacedDir = dictPlacedDir;
+    }
+
+    // TODO: This builds a FusionDictionary first and iterates it to add words to the binary
+    // dictionary. However, it is possible to just add words directly to the binary dictionary
+    // instead.
+    // In the long run, when we stop supporting version 2, FusionDictionary will become deprecated
+    // and we can remove it. Then we'll be able to just call BinaryDictionary directly.
+    @Override
+    public void writeDictionary(FusionDictionary dict, FormatOptions formatOptions)
+            throws IOException, UnsupportedFormatException {
+        if (formatOptions.mVersion != FormatSpec.VERSION4) {
+            throw new UnsupportedFormatException("File header has a wrong version number : "
+                    + formatOptions.mVersion);
+        }
+        if (!mDictPlacedDir.isDirectory()) {
+            throw new UnsupportedFormatException("Given path is not a directory.");
+        }
+        if (!BinaryDictionaryUtils.createEmptyDictFile(mDictPlacedDir.getAbsolutePath(),
+                FormatSpec.VERSION4, LocaleUtils.constructLocaleFromString(
+                dict.mOptions.mAttributes.get(DictionaryHeader.DICTIONARY_LOCALE_KEY)),
+                dict.mOptions.mAttributes)) {
+            throw new IOException("Cannot create dictionary file : "
+                + mDictPlacedDir.getAbsolutePath());
+        }
+        final BinaryDictionary binaryDict = new BinaryDictionary(mDictPlacedDir.getAbsolutePath(),
+                0l, mDictPlacedDir.length(), true /* useFullEditDistance */,
+                LocaleUtils.constructLocaleFromString(dict.mOptions.mAttributes.get(
+                        DictionaryHeader.DICTIONARY_LOCALE_KEY)),
+                Dictionary.TYPE_USER /* Dictionary type. Does not matter for us */,
+                true /* isUpdatable */);
+        if (!binaryDict.isValidDictionary()) {
+            // Somehow createEmptyDictFile returned true, but the file was not created correctly
+            throw new IOException("Cannot create dictionary file");
+        }
+        for (final WordProperty wordProperty : dict) {
+            if (!binaryDict.addUnigramEntry(wordProperty.mWord, wordProperty.getProbability(),
+                    wordProperty.mIsBeginningOfSentence, wordProperty.mIsNotAWord,
+                    wordProperty.mIsPossiblyOffensive, 0 /* timestamp */)) {
+                MakedictLog.e("Cannot add unigram entry for " + wordProperty.mWord);
+            }
+            if (binaryDict.needsToRunGC(true /* mindsBlockByGC */)) {
+                if (!binaryDict.flushWithGC()) {
+                    MakedictLog.e("Cannot flush dict with GC.");
+                    return;
+                }
+            }
+        }
+        for (final WordProperty word0Property : dict) {
+            if (!word0Property.mHasNgrams) continue;
+            // TODO: Support ngram.
+            for (final WeightedString word1 : word0Property.getBigrams()) {
+                final NgramContext ngramContext =
+                        new NgramContext(new NgramContext.WordInfo(word0Property.mWord));
+                if (!binaryDict.addNgramEntry(ngramContext, word1.mWord,
+                        word1.getProbability(), 0 /* timestamp */)) {
+                    MakedictLog.e("Cannot add n-gram entry for "
+                            + ngramContext + " -> " + word1.mWord);
+                    return;
+                }
+                if (binaryDict.needsToRunGC(true /* mindsBlockByGC */)) {
+                    if (!binaryDict.flushWithGC()) {
+                        MakedictLog.e("Cannot flush dict with GC.");
+                        return;
+                    }
+                }
+            }
+        }
+        if (!binaryDict.flushWithGC()) {
+            MakedictLog.e("Cannot flush dict with GC.");
+            return;
+        }
+        binaryDict.close();
+    }
+
+    @Override
+    public void setPosition(int position) {
+    }
+
+    @Override
+    public int getPosition() {
+        return 0;
+    }
+
+    @Override
+    public void writePtNodeCount(int ptNodeCount) {
+    }
+
+    @Override
+    public void writePtNode(PtNode ptNode, FusionDictionary dict,
+            HashMap<Integer, Integer> codePointToOneByteCodeMap) {
+    }
+}