How to make json_encode fail

Question

Trying to test a method that is doing a json_encode and throwing an exception if the encode fails. However, whatever I throw at json_encode it successfully encodes. Any idea what would be something simple to have it fail?

Answer 1

I think the smallest values to fail json_encode would be:

json_encode(NAN);
json_encode(INF);

Other candidate:

$a = array(&$a);
json_encode($a);

Answer 2

$text = "\xB1\x31";

$json  = json_encode($text);

For checking errors you can use json_last_error().