diff --git a/dictionary/dictionary.go b/dictionary/dictionary.go
index 7fa7625..083d072 100644
--- a/dictionary/dictionary.go
+++ b/dictionary/dictionary.go
@@ -16,6 +16,10 @@ type Dictionary struct {
 	sync.RWMutex
 }
 
+func New() *Dictionary {
+	return &Dictionary{freqMap: make(map[string]float64)}
+}
+
 func (d *Dictionary) addToken(token Token) {
 	d.freqMap[token.text] = token.frequency
 	d.total += token.frequency
@@ -84,6 +88,8 @@ func (d *Dictionary) loadDictionary(fileName string, isUserDictionary bool) erro
 
 	if !isUserDictionary && len(d.freqMap) > 0 {
 		d.freqMap = make(map[string]float64)
+		d.total = 0.0
+		d.logTotal = 0.0
 	}
 	for scanner.Scan() {
 		line = scanner.Text()
diff --git a/dictionary/dictionary_test.go b/dictionary/dictionary_test.go
new file mode 100644
index 0000000..1bd82af
--- /dev/null
+++ b/dictionary/dictionary_test.go
@@ -0,0 +1,45 @@
+package dictionary
+
+import (
+	"math"
+	"testing"
+)
+
+var d *Dictionary
+
+func init() {
+	d = New()
+}
+
+func TestLoadDictionary(t *testing.T) {
+	if err := d.LoadDictionary("../dict.txt"); err != nil {
+		t.Fatalf("Failed to load dict.txt, err = %s", err)
+	}
+	n := len(d.freqMap)
+
+	d.LoadDictionary("../foobar.txt")
+	if len(d.freqMap) == n {
+		t.Fatalf("Failed to load foobar.txt")
+	}
+}
+
+func TestLoadUserDictionary(t *testing.T) {
+	err := d.LoadUserDictionary("../userdict.txt")
+	if err != nil {
+		t.Fatalf("Failed to load userdict.txt, err = %s", err)
+	}
+	if f, _ := d.Frequency("八一双鹿"); f != 3.0 {
+		t.Fatalf("Wrong frequency for word \"八一双鹿\", expect 3.0, got %f", f)
+	}
+}
+
+func TestTotal(t *testing.T) {
+	d.LoadDictionary("../userdict.txt")
+
+	if d.Total() != 319.0 {
+		t.Fatalf("Wrong total for userdict.txt, expect 319.0, got %f", d.Total())
+	}
+	if d.LogTotal() != math.Log(319.0) {
+		t.Fatalf("Wrong total for userdict.txt, expect %f, got %f", math.Log(319.0), d.LogTotal())
+	}
+}