Ensure that time conversion for 0 returns nil timestamps or Time where IsZero returns true

internal/internal.go

@@ -53,5 +53,9 @@ func UnixNanoToTimestamp(u pdata.TimestampUnixNano) *timestamp.Timestamp {
 }
 
 func UnixNanoToTime(u pdata.TimestampUnixNano) time.Time {
+	// 0 is a special case and want to make sure we return a time that IsZero() returns true.
+	if u == 0 {
+		return time.Time{}
+	}
 	return time.Unix(0, int64(u)).UTC()
 }

internal/internal_test.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package internal_test
+package internal
 
 import (
 	"testing"
@@ -22,25 +22,30 @@ import (
 	"github.com/stretchr/testify/assert"
 
 	"go.opentelemetry.io/collector/consumer/pdata"
-	"go.opentelemetry.io/collector/internal"
 )
 
 func TestTimeConverters(t *testing.T) {
 	// Ensure that we nanoseconds but that they are also preserved.
 	t1 := time.Date(2018, 10, 31, 19, 43, 35, 789, time.UTC)
 
 	assert.EqualValues(t, int64(1541015015000000789), t1.UnixNano())
-	tp := internal.TimeToTimestamp(t1)
+	tp := TimeToTimestamp(t1)
 	assert.EqualValues(t, &timestamp.Timestamp{Seconds: 1541015015, Nanos: 789}, tp)
-	assert.EqualValues(t, int64(1541015015000000789), internal.TimestampToTime(tp).UnixNano())
+	assert.EqualValues(t, int64(1541015015000000789), TimestampToTime(tp).UnixNano())
 }
 
 func TestUnixNanosConverters(t *testing.T) {
 	t1 := time.Date(2020, 03, 24, 1, 13, 23, 789, time.UTC)
 	tun := pdata.TimestampUnixNano(t1.UnixNano())
 
 	assert.EqualValues(t, uint64(1585012403000000789), tun)
-	tp := internal.UnixNanoToTimestamp(tun)
+	tp := UnixNanoToTimestamp(tun)
 	assert.EqualValues(t, &timestamp.Timestamp{Seconds: 1585012403, Nanos: 789}, tp)
-	assert.EqualValues(t, tun, internal.TimestampToUnixNano(tp))
+	assert.EqualValues(t, tun, TimestampToUnixNano(tp))
+}
+
+func TestZeroTimestamps(t *testing.T) {
+	assert.Nil(t, TimeToTimestamp(time.Time{}))
+	assert.Nil(t, UnixNanoToTimestamp(0))
+	assert.True(t, UnixNanoToTime(0).IsZero())
 }