diff --git a/package.json b/package.json
index d6d80fed..280dc4ff 100644
--- a/package.json
+++ b/package.json
@@ -31,7 +31,7 @@
   },
   "devDependencies": {
     "browserify": "^6.3.2",
-    "chai": "^1.10.0",
+    "chai": "^3.2.0",
     "coveralls": "^2.11.2",
     "event-stream": "^3.1.7",
     "gulp": "^3.8.10",
diff --git a/test/dict/CharacterDefinitionTest.js b/test/dict/CharacterDefinitionTest.js
index c47fbc8c..efc6fb99 100644
--- a/test/dict/CharacterDefinitionTest.js
+++ b/test/dict/CharacterDefinitionTest.js
@@ -71,43 +71,43 @@ describe("CharacterDefinition from char.def", function () {
     });
 
     it("SPACE class definition of INVOKE: false, GROUP: true, LENGTH: 0", function () {
-        expect(char_def.lookup(" ").is_always_invoke).to.be.false();
-        expect(char_def.lookup(" ").is_grouping).to.be.true();
+        expect(char_def.lookup(" ").is_always_invoke).to.be.false;
+        expect(char_def.lookup(" ").is_grouping).to.be.true;
         expect(char_def.lookup(" ").max_length).to.be.equal(0);
     });
     it("KANJI class definition of INVOKE: false, GROUP: false, LENGTH: 2", function () {
-        expect(char_def.lookup("日").is_always_invoke).to.be.false();
-        expect(char_def.lookup("日").is_grouping).to.be.false();
+        expect(char_def.lookup("日").is_always_invoke).to.be.false;
+        expect(char_def.lookup("日").is_grouping).to.be.false;
         expect(char_def.lookup("日").max_length).to.be.equal(2);
     });
     it("SYMBOL class definition of INVOKE: true, GROUP: true, LENGTH: 0", function () {
-        expect(char_def.lookup("!").is_always_invoke).to.be.true();
-        expect(char_def.lookup("!").is_grouping).to.be.true();
+        expect(char_def.lookup("!").is_always_invoke).to.be.true;
+        expect(char_def.lookup("!").is_grouping).to.be.true;
         expect(char_def.lookup("!").max_length).to.be.equal(0);
     });
     it("NUMERIC class definition of INVOKE: true, GROUP: true, LENGTH: 0", function () {
-        expect(char_def.lookup("1").is_always_invoke).to.be.true();
-        expect(char_def.lookup("1").is_grouping).to.be.true();
+        expect(char_def.lookup("1").is_always_invoke).to.be.true;
+        expect(char_def.lookup("1").is_grouping).to.be.true;
         expect(char_def.lookup("1").max_length).to.be.equal(0);
     });
     it("ALPHA class definition of INVOKE: true, GROUP: true, LENGTH: 0", function () {
-        expect(char_def.lookup("A").is_always_invoke).to.be.true();
-        expect(char_def.lookup("A").is_grouping).to.be.true();
+        expect(char_def.lookup("A").is_always_invoke).to.be.true;
+        expect(char_def.lookup("A").is_grouping).to.be.true;
         expect(char_def.lookup("A").max_length).to.be.equal(0);
     });
     it("HIRAGANA class definition of INVOKE: false, GROUP: true, LENGTH: 2", function () {
-        expect(char_def.lookup("あ").is_always_invoke).to.be.false();
-        expect(char_def.lookup("あ").is_grouping).to.be.true();
+        expect(char_def.lookup("あ").is_always_invoke).to.be.false;
+        expect(char_def.lookup("あ").is_grouping).to.be.true;
         expect(char_def.lookup("あ").max_length).to.be.equal(2);
     });
     it("KATAKANA class definition of INVOKE: true, GROUP: true, LENGTH: 2", function () {
-        expect(char_def.lookup("ア").is_always_invoke).to.be.true();
-        expect(char_def.lookup("ア").is_grouping).to.be.true();
+        expect(char_def.lookup("ア").is_always_invoke).to.be.true;
+        expect(char_def.lookup("ア").is_grouping).to.be.true;
         expect(char_def.lookup("ア").max_length).to.be.equal(2);
     });
     it("KANJINUMERIC class definition of INVOKE: true, GROUP: true, LENGTH: 0", function () {
-        expect(char_def.lookup("一").is_always_invoke).to.be.true();
-        expect(char_def.lookup("一").is_grouping).to.be.true();
+        expect(char_def.lookup("一").is_always_invoke).to.be.true;
+        expect(char_def.lookup("一").is_grouping).to.be.true;
         expect(char_def.lookup("一").max_length).to.be.equal(0);
     });
     it("Save and load", function () {
diff --git a/test/util/DictionaryBuilderTest.js b/test/util/DictionaryBuilderTest.js
index 9647d293..4551977f 100644
--- a/test/util/DictionaryBuilderTest.js
+++ b/test/util/DictionaryBuilderTest.js
@@ -74,20 +74,20 @@ describe("DictionaryBuilder", function () {
     });
 
     it("Dictionary not to be null", function () {
-        expect(kuromoji_dic).not.to.be.null();
+        expect(kuromoji_dic).not.to.be.null;
     });
     it("TokenInfoDictionary not to be null", function () {
-        expect(kuromoji_dic.token_info_dictionary).not.to.be.null();
+        expect(kuromoji_dic.token_info_dictionary).not.to.be.null;
     });
     it("TokenInfoDictionary", function () {
         // expect(kuromoji_dic.token_info_dictionary.getFeatures("1467000")).to.have.length.above(1);
         expect(kuromoji_dic.token_info_dictionary.dictionary.buffer).to.have.length.above(1);
     });
     it("DoubleArray not to be null", function () {
-        expect(kuromoji_dic.trie).not.to.be.null();
+        expect(kuromoji_dic.trie).not.to.be.null;
     });
     it("ConnectionCosts not to be null", function () {
-        expect(kuromoji_dic.connection_costs).not.to.be.null();
+        expect(kuromoji_dic.connection_costs).not.to.be.null;
     });
     it("Tokenize simple test", function () {
         var tokenizer = new Tokenizer(kuromoji_dic);