add Timeconstructor

Author: Hixon10

bson/constructor.go

@@ -15,6 +15,7 @@ import (
 	"github.com/mongodb/mongo-go-driver/bson/decimal"
 	"github.com/mongodb/mongo-go-driver/bson/elements"
 	"github.com/mongodb/mongo-go-driver/bson/objectid"
+	"time"
 )
 
 // EC is a convenience variable provided for access to the ElementConstructor methods.
@@ -325,6 +326,7 @@ func (ElementConstructor) Boolean(key string, b bool) *Element {
 }
 
 // DateTime creates a datetime element with the given key and value.
+// dt represents milliseconds since the Unix epoch
 func (ElementConstructor) DateTime(key string, dt int64) *Element {
 	size := uint32(1 + len(key) + 1 + 8)
 	elem := newElement(0, 1+uint32(len(key))+1)
@@ -338,6 +340,11 @@ func (ElementConstructor) DateTime(key string, dt int64) *Element {
 	return elem
 }
 
+// Time creates a datetime element with the given key and value.
+func (c ElementConstructor) Time(key string, time time.Time) *Element {
+	return c.DateTime(key, time.Unix()*1000)
+}
+
 // Null creates a null element with the given key.
 func (ElementConstructor) Null(key string) *Element {
 	size := uint32(1 + len(key) + 1)

bson/constructor_test.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/mongodb/mongo-go-driver/bson/decimal"
 	"github.com/stretchr/testify/require"
+	"time"
 )
 
 func requireElementsEqual(t *testing.T, expected *Element, actual *Element) {
@@ -271,6 +272,25 @@ func TestConstructor(t *testing.T) {
 			requireElementsEqual(t, expected, actual)
 		})
 
+		t.Run("time", func(t *testing.T) {
+			buf := []byte{
+				// type
+				0x9,
+				// key
+				0x66, 0x6f, 0x6f, 0x0,
+				// value
+				0xC8, 0x6C, 0x3C, 0xAF, 0x60, 0x1, 0x0, 0x0,
+			}
+
+			expected := &Element{&Value{start: 0, offset: 5, data: buf, d: nil}}
+
+			actualTime := EC.Time("foo", time.Date(2018, 1, 1, 1, 1, 1, 1, time.UTC))
+			actualDateTime := EC.DateTime("foo", 1514768461000)
+
+			requireElementsEqual(t, expected, actualTime)
+			requireElementsEqual(t, expected, actualDateTime)
+		})
+
 		t.Run("Null", func(t *testing.T) {
 			buf := []byte{
 				// type