feat:add AddYear func (#96)

Co-authored-by: leitao <leitao@kezaihui.com>

datetime/datetime.go

@@ -72,6 +72,10 @@ func AddDay(t time.Time, day int64) time.Time {
 	return t.Add(24 * time.Hour * time.Duration(day))
 }
 
+func AddYear(t time.Time, year int64) time.Time {
+	return t.Add(365 * 24 * time.Hour * time.Duration(year))
+}
+
 // GetNowDate return format yyyy-mm-dd of current date.
 // Play: https://go.dev/play/p/PvfkPpcpBBf
 func GetNowDate() string {

datetime/datetime_example_test.go

@@ -57,6 +57,23 @@ func ExampleAddMinute() {
 	// -2m0s
 }
 
+func ExampleAddYear() {
+	now := time.Now()
+
+	after1Year := AddYear(now, 1)
+	diff1 := after1Year.Sub(now)
+
+	before1Year := AddYear(now, -1)
+	diff2 := before1Year.Sub(now)
+
+	fmt.Println(diff1)
+	fmt.Println(diff2)
+
+	// Output:
+	// 8760h0m0s
+	// -8760h0m0s
+}
+
 func ExampleGetNowDate() {
 	result := GetNowDate()
 

datetime/datetime_test.go

@@ -7,6 +7,19 @@ import (
 	"github.com/duke-git/lancet/v2/internal"
 )
 
+func TestAddYear(t *testing.T) {
+	assert := internal.NewAssert(t, "TestAddDay")
+
+	now := time.Now()
+	after2Years := AddYear(now, 1)
+	diff1 := after2Years.Sub(now)
+	assert.Equal(float64(8760), diff1.Hours())
+
+	before2Years := AddYear(now, -1)
+	diff2 := before2Years.Sub(now)
+	assert.Equal(float64(-8760), diff2.Hours())
+}
+
 func TestAddDay(t *testing.T) {
 	assert := internal.NewAssert(t, "TestAddDay")