diff --git a/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java b/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
index ed80a96..9f5cd16 100644
--- a/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
+++ b/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
@@ -105,6 +105,9 @@
     /** Whether to support dynamically updating the dictionary */
     private final boolean mIsUpdatable;
 
+    /** Dictionary file */
+    private final File mDictFile;
+
     // TODO: remove, once dynamic operations is serialized
     /** Controls updating the shared binary dictionary file across multiple instances. */
     private final DictionaryUpdateController mDictNameDictionaryUpdateController;
@@ -146,7 +149,7 @@
     }
 
     private File getDictFile() {
-        return new File(mContext.getFilesDir(), mDictName + DICT_FILE_EXTENSION);
+        return mDictFile;
     }
 
     /**
@@ -200,11 +203,20 @@
      */
     public ExpandableBinaryDictionary(final Context context, final String dictName,
             final Locale locale, final String dictType, final boolean isUpdatable) {
+        this(context, dictName, locale, dictType, isUpdatable,
+                new File(context.getFilesDir(), dictName + DICT_FILE_EXTENSION));
+    }
+
+    // Creates an instance that uses a given dictionary file.
+    public ExpandableBinaryDictionary(final Context context, final String dictName,
+            final Locale locale, final String dictType, final boolean isUpdatable,
+            final File dictFile) {
         super(dictType);
         mDictName = dictName;
         mContext = context;
         mLocale = locale;
         mIsUpdatable = isUpdatable;
+        mDictFile = dictFile;
         mBinaryDictionary = null;
         mDictNameDictionaryUpdateController = getDictionaryUpdateController(dictName);
         // Currently, only dynamic personalization dictionary is updatable.
diff --git a/java/src/com/android/inputmethod/latin/personalization/DecayingExpandableBinaryDictionaryBase.java b/java/src/com/android/inputmethod/latin/personalization/DecayingExpandableBinaryDictionaryBase.java
index ceec3e1..296733f 100644
--- a/java/src/com/android/inputmethod/latin/personalization/DecayingExpandableBinaryDictionaryBase.java
+++ b/java/src/com/android/inputmethod/latin/personalization/DecayingExpandableBinaryDictionaryBase.java
@@ -70,6 +70,19 @@
         }
     }
 
+    // Creates an instance that uses a given dictionary file for testing.
+    @UsedForTesting
+    /* package */ DecayingExpandableBinaryDictionaryBase(final Context context,
+            final Locale locale, final String dictionaryType, final String dictName,
+            final File dictFile) {
+        super(context, dictName, locale, dictionaryType, true, dictFile);
+        mLocale = locale;
+        mDictName = dictName;
+        if (mLocale != null && mLocale.toString().length() > 1) {
+            reloadDictionaryIfRequired();
+        }
+    }
+
     @Override
     public void close() {
         if (DBG_DUMP_ON_CLOSE) {
diff --git a/java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionary.java b/java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionary.java
index b1ec76f..596562f 100644
--- a/java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionary.java
+++ b/java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionary.java
@@ -16,9 +16,11 @@
 
 package com.android.inputmethod.latin.personalization;
 
+import com.android.inputmethod.annotations.UsedForTesting;
 import com.android.inputmethod.latin.Dictionary;
 import com.android.inputmethod.latin.utils.CollectionUtils;
 
+import java.io.File;
 import java.util.ArrayList;
 import java.util.Locale;
 
@@ -35,6 +37,14 @@
                 getDictNameWithLocale(NAME, locale));
     }
 
+    // Creates an instance that uses a given dictionary file for testing.
+    @UsedForTesting
+    public PersonalizationDictionary(final Context context, final Locale locale,
+            final File dictFile) {
+        super(context, locale, Dictionary.TYPE_PERSONALIZATION, getDictNameWithLocale(NAME, locale),
+                dictFile);
+    }
+
     public void registerUpdateSession(PersonalizationDictionaryUpdateSession session) {
         session.setPredictionDictionary(this);
         mSessions.add(session);
diff --git a/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java b/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java
index 3f03de0..868f21c 100644
--- a/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java
+++ b/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java
@@ -16,8 +16,10 @@
 
 package com.android.inputmethod.latin.personalization;
 
+import com.android.inputmethod.annotations.UsedForTesting;
 import com.android.inputmethod.latin.Dictionary;
 
+import java.io.File;
 import java.util.Locale;
 
 import android.content.Context;
@@ -33,6 +35,14 @@
         super(context, locale, Dictionary.TYPE_USER_HISTORY, getDictNameWithLocale(NAME, locale));
     }
 
+    // Creates an instance that uses a given dictionary file for testing.
+    @UsedForTesting
+    public UserHistoryDictionary(final Context context, final Locale locale,
+            final File dictFile) {
+        super(context, locale, Dictionary.TYPE_USER_HISTORY, getDictNameWithLocale(NAME, locale),
+                dictFile);
+    }
+
     public void cancelAddingUserHistory(final String word0, final String word1) {
         removeBigramDynamically(word0, word1);
     }