tests/check-qjson: fix a leak

Spotted by ASAN:
=================================================================
==11893==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 1120 byte(s) in 28 object(s) allocated from:
    #0 0x7fd0515b0c48 in malloc (/lib64/libasan.so.5+0xeec48)
    #1 0x7fd050ffa3c5 in g_malloc (/lib64/libglib-2.0.so.0+0x523c5)
    #2 0x559e708b56a4 in qstring_from_str /home/elmarco/src/qq/qobject/qstring.c:66
    qemu#3 0x559e708b4fe0 in qstring_new /home/elmarco/src/qq/qobject/qstring.c:23
    qemu#4 0x559e708bda7d in parse_string /home/elmarco/src/qq/qobject/json-parser.c:143
    qemu#5 0x559e708c1009 in parse_literal /home/elmarco/src/qq/qobject/json-parser.c:484
    qemu#6 0x559e708c1627 in parse_value /home/elmarco/src/qq/qobject/json-parser.c:547
    qemu#7 0x559e708c1c67 in json_parser_parse /home/elmarco/src/qq/qobject/json-parser.c:573
    qemu#8 0x559e708bc0ff in json_message_process_token /home/elmarco/src/qq/qobject/json-streamer.c:92
    qemu#9 0x559e708d1655 in json_lexer_feed_char /home/elmarco/src/qq/qobject/json-lexer.c:292
    qemu#10 0x559e708d1fe1 in json_lexer_feed /home/elmarco/src/qq/qobject/json-lexer.c:339
    qemu#11 0x559e708bc856 in json_message_parser_feed /home/elmarco/src/qq/qobject/json-streamer.c:121
    qemu#12 0x559e708b8b4b in qobject_from_jsonv /home/elmarco/src/qq/qobject/qjson.c:69
    qemu#13 0x559e708b8d02 in qobject_from_json /home/elmarco/src/qq/qobject/qjson.c:83
    qemu#14 0x559e708a74ae in from_json_str /home/elmarco/src/qq/tests/check-qjson.c:30
    qemu#15 0x559e708a9f83 in utf8_string /home/elmarco/src/qq/tests/check-qjson.c:781
    qemu#16 0x7fd05101bc49 in test_case_run gtestutils.c:2255
    qemu#17 0x7fd05101bc49 in g_test_run_suite_internal gtestutils.c:2339

Signed-off-by: Marc-André Lureau <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Markus Armbruster <[email protected]>
Signed-off-by: Markus Armbruster <[email protected]>

Author: elmarco

tests/check-qjson.c

@@ -780,6 +780,7 @@ static void utf8_string(void)
             if (!strstr(json_out, "\\uFFFD")) {
                 str = from_json_str(json_out, j, &error_abort);
                 g_assert_cmpstr(qstring_get_try_str(str), ==, utf8_in);
+                qobject_unref(str);
             }
         }
     }