add test case

utils_test.go

@@ -1,6 +1,8 @@
 package godns
 
 import (
+	"os"
+	"strings"
 	"testing"
 )
 
@@ -47,3 +49,28 @@ func TestCheckSettings(t *testing.T) {
 		t.Error("HE setting without password, should be faild")
 	}
 }
+
+func TestSaveCurrentIP(t *testing.T) {
+	SaveCurrentIP("1.2.3.4")
+
+	if _, err := os.Stat("./.current_ip"); os.IsNotExist(err) {
+		t.Error(".current_ip file should exists")
+	}
+
+	savedIP := LoadCurrentIP()
+
+	if strings.TrimRight(savedIP, "\n") != "1.2.3.4" {
+		t.Error("saved IP should be equal to 1.2.3.4")
+	}
+
+	//Cleanup
+	os.Remove("./.current_ip")
+}
+
+func TestLoadCurrentIP(t *testing.T) {
+	ip := LoadCurrentIP()
+
+	if ip != "" {
+		t.Error("current ip file should be empth")
+	}
+}