diff --git a/internal/ngram/ngram_test.go b/internal/ngram/ngram_test.go
index 5852812..0b3c212 100644
--- a/internal/ngram/ngram_test.go
+++ b/internal/ngram/ngram_test.go
@@ -7,10 +7,9 @@ import (
 	"github.com/gslin/go-ir-playground/internal/ngram"
 )
 
-func testBigram(t *testing.T) {
+func TestBigram(t *testing.T) {
 	a := ngram.Bigram("test")
-	assert.Equal(t, len(a), 1)
-	assert.Equal(t, a[0], "test")
+	assert.Equal(t, len(a), 0)
 
 	a = ngram.Bigram("測試")
 	assert.Equal(t, len(a), 1)