diff --git a/vlib/json/json_test.v b/vlib/json/json_test.v
index 39444c0d67..75407d8b04 100644
--- a/vlib/json/json_test.v
+++ b/vlib/json/json_test.v
@@ -59,6 +59,7 @@ struct SomeGame {
 }
 
 fn test_encode_decode_sumtype() ? {
+	t := time.now()
 	game := SomeGame{
 		title: 'Super Mega Game'
 		player: Human{'Monke'}
@@ -67,7 +68,7 @@ fn test_encode_decode_sumtype() ? {
 			Item{'Cookie'},
 			Animal.cat,
 			'Stool',
-			time.now(),
+			t,
 		]
 	}
 	eprintln('Game: $game')
@@ -75,8 +76,9 @@ fn test_encode_decode_sumtype() ? {
 	enc := json.encode(game)
 	eprintln('Encoded Game: $enc')
 
-	dec := json.decode(SomeGame, enc) ?
+	assert enc == '{"title":"Super Mega Game","player":{"name":"Monke","_type":"Human"},"other":[{"tag":"Pen","_type":"Item"},{"tag":"Cookie","_type":"Item"},1,"Stool",{"_type":"Time","value":$t.unix_time()}]}'
 
+	dec := json.decode(SomeGame, enc) ?
 	eprintln('Decoded Game: $dec')
 
 	assert game.title == dec.title