add clock

utils/clock/clock.go

@@ -0,0 +1,54 @@
+package clock
+
+import (
+	"sync"
+	"time"
+)
+
+const (
+	BangkokTZ = "Asia/Bangkok"
+
+	DateTimeFormat = "2006-01-02 15:04:05"
+	DateFormat     = "2006-01-02"
+)
+
+var (
+	instance = time.Now
+	lock     = sync.Mutex{}
+)
+
+// NowBKK returns current time in BKK timezone
+func NowBKK() time.Time {
+	loc, _ := time.LoadLocation(BangkokTZ)
+	return Now().In(loc)
+}
+
+// Now returns current time
+func Now() time.Time {
+	return instance()
+}
+
+// ToString returns date time in string format
+func ToString(n time.Time) string {
+	return n.Format(DateTimeFormat)
+}
+
+// ToDateString returns date in string format
+func ToDateString(n time.Time) string {
+	return n.Format(DateFormat)
+}
+
+// Freeze sets the instance of time
+func Freeze(fn func() time.Time) {
+	lock.Lock()
+	defer lock.Unlock()
+	instance = fn
+}
+
+// UnFreeze removes all applied time
+func UnFreeze() {
+	lock.Lock()
+	defer lock.Unlock()
+
+	instance = time.Now
+}

utils/clock/clock_test.go

@@ -0,0 +1,66 @@
+package clock_test
+
+import (
+	"github.com/hokkung/go-groceries/utils/clock"
+	"github.com/stretchr/testify/assert"
+	"testing"
+	"time"
+)
+
+var mockInstance = func() time.Time {
+	return time.Date(2024, 01, 01, 10, 0, 0, 0, time.UTC)
+}
+
+func TestMain(m *testing.M) {
+	clock.Freeze(mockInstance)
+	m.Run()
+	clock.UnFreeze()
+}
+
+func TestNow(t *testing.T) {
+	exp := mockInstance()
+	act := clock.Now()
+
+	assert.Equal(t, exp, act)
+}
+
+func TestNowBKK(t *testing.T) {
+	loc, _ := time.LoadLocation(clock.BangkokTZ)
+	exp := mockInstance().In(loc)
+
+	act := clock.NowBKK()
+
+	assert.Equal(t, exp, act)
+}
+
+func TestToString(t *testing.T) {
+	tt := mockInstance()
+	exp := "2024-01-01 10:00:00"
+
+	act := clock.ToString(tt)
+
+	assert.Equal(t, exp, act)
+}
+
+func TestToDateString(t *testing.T) {
+	tt := mockInstance()
+	exp := "2024-01-01"
+
+	act := clock.ToDateString(tt)
+
+	assert.Equal(t, exp, act)
+}
+
+func TestUnFreeze(t *testing.T) {
+	exp := mockInstance()
+
+	act := clock.Now()
+
+	assert.Equal(t, exp, act)
+
+	clock.UnFreeze()
+
+	act2 := clock.Now()
+
+	assert.True(t, act.Before(act2))
+}