time: fix JSON-related methods

Author: gbrlsnchs

time.go

@@ -17,32 +17,27 @@ func NumericDate(tt time.Time) *Time {
 	if tt.Before(internal.Epoch) {
 		tt = internal.Epoch
 	}
-	return &Time{time.Unix(tt.Unix(), 0)}
-}
-
-// IsZero checks whether no seconds have elapsed since epoch.
-func (t *Time) IsZero() bool {
-	return t == nil || t.Before(internal.Epoch) || t.Equal(internal.Epoch)
+	return &Time{time.Unix(tt.Unix(), 0)} // set time using Unix time
 }
 
 // MarshalJSON implements a marshaling function for time-related claims.
-func (t *Time) MarshalJSON() ([]byte, error) {
-	if t.IsZero() {
+func (t Time) MarshalJSON() ([]byte, error) {
+	if t.Before(internal.Epoch) {
 		return json.Marshal(0)
 	}
 	return json.Marshal(t.Unix())
 }
 
 // UnmarshalJSON implements an unmarshaling function for time-related claims.
 func (t *Time) UnmarshalJSON(b []byte) error {
-	var unix int64
+	var unix *int64
 	if err := json.Unmarshal(b, &unix); err != nil {
 		return err
 	}
-	if unix <= 0 {
+	if unix == nil {
 		return nil
 	}
-	tt := time.Unix(unix, 0)
+	tt := time.Unix(*unix, 0)
 	if tt.Before(internal.Epoch) {
 		tt = internal.Epoch
 	}

time_test.go

@@ -18,6 +18,7 @@ func TestTimeMarshalJSON(t *testing.T) {
 		{jwt.Time{}, 0},
 		{jwt.Time{now}, now.Unix()},
 		{jwt.Time{now.Add(24 * time.Hour)}, now.Add(24 * time.Hour).Unix()},
+		{jwt.Time{now.Add(24 * 30 * 12 * time.Hour)}, now.Add(24 * 30 * 12 * time.Hour).Unix()},
 	}
 	for _, tc := range testCases {
 		t.Run("", func(t *testing.T) {
@@ -39,17 +40,23 @@ func TestTimeMarshalJSON(t *testing.T) {
 func TestTimeUnmarshalJSON(t *testing.T) {
 	now := time.Now()
 	testCases := []struct {
-		n    int64
-		want jwt.Time
+		n     int64
+		want  jwt.Time
+		isNil bool
 	}{
-		{now.Unix(), jwt.Time{now}},
-		{internal.Epoch.Unix() - 1337, jwt.Time{}},
-		{internal.Epoch.Unix(), jwt.Time{}},
-		{internal.Epoch.Unix() + 1337, jwt.Time{internal.Epoch.Add(1337 * time.Second)}},
+		{now.Unix(), jwt.Time{now}, false},
+		{internal.Epoch.Unix() - 1337, jwt.Time{internal.Epoch}, false},
+		{internal.Epoch.Unix(), jwt.Time{internal.Epoch}, false},
+		{internal.Epoch.Unix() + 1337, jwt.Time{internal.Epoch.Add(1337 * time.Second)}, false},
+		{0, jwt.Time{}, true},
 	}
 	for _, tc := range testCases {
 		t.Run("", func(t *testing.T) {
-			b, err := json.Marshal(tc.n)
+			var n *int64
+			if !tc.isNil {
+				n = &tc.n
+			}
+			b, err := json.Marshal(n)
 			if err != nil {
 				t.Fatal(err)
 			}