diff --git a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Dicttool.java b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Dicttool.java
index 7b311c3..cacee52 100644
--- a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Dicttool.java
+++ b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Dicttool.java
@@ -72,15 +72,21 @@
         return command;
     }
 
-    private void execute(final String[] arguments) {
+    /**
+     * Executes the specified command with the specified arguments.
+     * @param arguments the arguments passed to dicttool.
+     * @return 0 for success, an error code otherwise (always 1 at the moment)
+     */
+    private int execute(final String[] arguments) {
         final Command command = getCommand(arguments);
         try {
             command.run();
+            return 0;
         } catch (Exception e) {
             System.out.println("Exception while processing command "
                     + command.getClass().getSimpleName() + " : " + e);
             e.printStackTrace();
-            return;
+            return 1;
         }
     }
 
@@ -89,6 +95,7 @@
             help();
             return;
         }
-        new Dicttool().execute(arguments);
+        // Exit with the success/error code from #execute() as status.
+        System.exit(new Dicttool().execute(arguments));
     }
 }
diff --git a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Test.java b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Test.java
index df5ea35..972b6e7 100644
--- a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Test.java
+++ b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Test.java
@@ -16,10 +16,12 @@
 
 package com.android.inputmethod.latin.dicttool;
 
+import com.android.inputmethod.latin.makedict.BinaryDictIOTests;
 import com.android.inputmethod.latin.makedict.BinaryDictIOUtilsTests;
 import com.android.inputmethod.latin.makedict.BinaryDictInputOutputTest;
 import com.android.inputmethod.latin.makedict.FusionDictionaryTest;
 
+import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
@@ -36,7 +38,8 @@
         BinaryDictOffdeviceUtilsTests.class,
         FusionDictionaryTest.class,
         BinaryDictInputOutputTest.class,
-        BinaryDictIOUtilsTests.class
+        BinaryDictIOUtilsTests.class,
+        BinaryDictIOTests.class
     };
     private ArrayList<Method> mAllTestMethods = new ArrayList<Method>();
     private ArrayList<String> mUsedTestMethods = new ArrayList<String>();
@@ -86,12 +89,19 @@
         for (final Method m : mAllTestMethods) {
             final Class<?> declaringClass = m.getDeclaringClass();
             if (!mUsedTestMethods.isEmpty() && !mUsedTestMethods.contains(m.getName())) continue;
-            final Object instance;
-            if (BinaryDictIOUtilsTests.class == declaringClass) {
-                instance = new BinaryDictIOUtilsTests(mSeed, mMaxUnigrams);
-            } else {
-                instance = declaringClass.newInstance();
+            // Some of the test classes expose a two-argument constructor, taking a long as a
+            // seed for Random, and an int for a vocabulary size to test the dictionary with. They
+            // correspond respectively to the -s and -m numerical arguments to this command, which
+            // are stored in mSeed and mMaxUnigrams. If the two-arguments constructor is present,
+            // then invoke it; otherwise, invoke the default constructor.
+            Constructor<?> twoArgsConstructor = null;
+            try {
+                twoArgsConstructor = declaringClass.getDeclaredConstructor(Long.TYPE, Integer.TYPE);
+            } catch (NoSuchMethodException e) {
+                // No constructor with two args
             }
+            final Object instance = null == twoArgsConstructor ? declaringClass.newInstance()
+                    : twoArgsConstructor.newInstance(mSeed, mMaxUnigrams);
             m.invoke(instance);
         }
     }