Patchwork [v2] check-qjson: More thorough testing of UTF-8 in strings

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Submitter Markus Armbruster
Date Feb. 5, 2013, 8:30 a.m.
Message ID <1360053055-26312-1-git-send-email-armbru@redhat.com>
Download mbox | patch
Permalink /patch/218173/
State New
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Markus Armbruster - Feb. 5, 2013, 8:30 a.m.
Test cases are scraped from Markus Kuhn's UTF-8 decoder capability and
stress test at
http://www.cl.cam.ac.uk/~mgk25/ucs/examples/UTF-8-test.txt

Unfortunately, both JSON parser and formatter misbehave right now.
This test expects current, incorrect results.  They're all clearly
marked, and are to be replaced by correct ones as the bugs get fixed.
See comments in new utf8_string() for details.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 tests/check-qjson.c | 664 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 664 insertions(+)

v2: long lines wrapped, a few comments improved
Luiz Capitulino - Feb. 6, 2013, 12:10 p.m.
On Tue,  5 Feb 2013 09:30:55 +0100
Markus Armbruster <armbru@redhat.com> wrote:

> Test cases are scraped from Markus Kuhn's UTF-8 decoder capability and
> stress test at
> http://www.cl.cam.ac.uk/~mgk25/ucs/examples/UTF-8-test.txt
> 
> Unfortunately, both JSON parser and formatter misbehave right now.
> This test expects current, incorrect results.  They're all clearly
> marked, and are to be replaced by correct ones as the bugs get fixed.
> See comments in new utf8_string() for details.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>

Applied to the qmp-next branch, thanks.

> ---
>  tests/check-qjson.c | 664 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 664 insertions(+)
> 
> v2: long lines wrapped, a few comments improved
> 
> diff --git a/tests/check-qjson.c b/tests/check-qjson.c
> index 32ffb43..ec85a0c 100644
> --- a/tests/check-qjson.c
> +++ b/tests/check-qjson.c
> @@ -1,8 +1,10 @@
>  /*
>   * Copyright IBM, Corp. 2009
> + * Copyright (c) 2013 Red Hat Inc.
>   *
>   * Authors:
>   *  Anthony Liguori   <aliguori@us.ibm.com>
> + *  Markus Armbruster <armbru@redhat.com>,
>   *
>   * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
>   * See the COPYING.LIB file in the top-level directory.
> @@ -131,6 +133,667 @@ static void single_quote_string(void)
>      }
>  }
>  
> +static void utf8_string(void)
> +{
> +    /*
> +     * FIXME Current behavior for invalid UTF-8 sequences is
> +     * incorrect.  This test expects current, incorrect results.
> +     * They're all marked "bug:" below, and are to be replaced by
> +     * correct ones as the bugs get fixed.
> +     *
> +     * The JSON parser rejects some invalid sequences, but accepts
> +     * others without correcting the problem.
> +     *
> +     * The JSON formatter replaces some invalid sequences by U+FFFF (a
> +     * noncharacter), and goes wonky for others.
> +     *
> +     * For both directions, we should either reject all invalid
> +     * sequences, or minimize overlong sequences and replace all other
> +     * invalid sequences by a suitable replacement character.  A
> +     * common choice for replacement is U+FFFD.
> +     *
> +     * Problem: we can't easily deal with embedded U+0000.  Parsing
> +     * the JSON string "this \\u0000" is fun" yields "this \0 is fun",
> +     * which gets misinterpreted as NUL-terminated "this ".  We should
> +     * consider using overlong encoding \xC0\x80 for U+0000 ("modified
> +     * UTF-8").
> +     *
> +     * Test cases are scraped from Markus Kuhn's UTF-8 decoder
> +     * capability and stress test at
> +     * http://www.cl.cam.ac.uk/~mgk25/ucs/examples/UTF-8-test.txt
> +     */
> +    static const struct {
> +        const char *json_in;
> +        const char *utf8_out;
> +        const char *json_out;   /* defaults to @json_in */
> +        const char *utf8_in;    /* defaults to @utf8_out */
> +    } test_cases[] = {
> +        /*
> +         * Bug markers used here:
> +         * - bug: not corrected
> +         *   JSON parser fails to correct invalid sequence(s)
> +         * - bug: rejected
> +         *   JSON parser rejects invalid sequence(s)
> +         *   We may choose to define this as feature
> +         * - bug: want "\"...\""
> +         *   JSON formatter produces incorrect result, this is the
> +         *   correct one, assuming replacement character U+FFFF
> +         * - bug: want "..." (no \")
> +         *   JSON parser produces incorrect result, this is the
> +         *   correct one, assuming replacement character U+FFFF
> +         *   We may choose to reject instead of replace
> +         * Not marked explicitly, but trivial to find:
> +         * - JSON formatter replacing invalid sequence by \\uFFFF is a
> +         *   bug if we want it to fail for invalid sequences.
> +         */
> +
> +        /* 1  Some correct UTF-8 text */
> +        {
> +            /* a bit of German */
> +            "\"Falsches \xC3\x9C" "ben von Xylophonmusik qu\xC3\xA4lt"
> +            " jeden gr\xC3\xB6\xC3\x9F" "eren Zwerg.\"",
> +            "Falsches \xC3\x9C" "ben von Xylophonmusik qu\xC3\xA4lt"
> +            " jeden gr\xC3\xB6\xC3\x9F" "eren Zwerg.",
> +            "\"Falsches \\u00DCben von Xylophonmusik qu\\u00E4lt"
> +            " jeden gr\\u00F6\\u00DFeren Zwerg.\"",
> +        },
> +        {
> +            /* a bit of Greek */
> +            "\"\xCE\xBA\xE1\xBD\xB9\xCF\x83\xCE\xBC\xCE\xB5\"",
> +            "\xCE\xBA\xE1\xBD\xB9\xCF\x83\xCE\xBC\xCE\xB5",
> +            "\"\\u03BA\\u1F79\\u03C3\\u03BC\\u03B5\"",
> +        },
> +        /* 2  Boundary condition test cases */
> +        /* 2.1  First possible sequence of a certain length */
> +        /* 2.1.1  1 byte U+0000 */
> +        {
> +            "\"\\u0000\"",
> +            "",                 /* bug: want overlong "\xC0\x80" */
> +            "\"\"",             /* bug: want "\"\\u0000\"" */
> +        },
> +        /* 2.1.2  2 bytes U+0080 */
> +        {
> +            "\"\xC2\x80\"",
> +            "\xC2\x80",
> +            "\"\\u0080\"",
> +        },
> +        /* 2.1.3  3 bytes U+0800 */
> +        {
> +            "\"\xE0\xA0\x80\"",
> +            "\xE0\xA0\x80",
> +            "\"\\u0800\"",
> +        },
> +        /* 2.1.4  4 bytes U+10000 */
> +        {
> +            "\"\xF0\x90\x80\x80\"",
> +            "\xF0\x90\x80\x80",
> +            "\"\\u0400\\uFFFF\"", /* bug: want "\"\\uD800\\uDC00\"" */
> +        },
> +        /* 2.1.5  5 bytes U+200000 */
> +        {
> +            "\"\xF8\x88\x80\x80\x80\"",
> +            NULL,                        /* bug: rejected */
> +            "\"\\u8200\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +            "\xF8\x88\x80\x80\x80",
> +        },
> +        /* 2.1.6  6 bytes U+4000000 */
> +        {
> +            "\"\xFC\x84\x80\x80\x80\x80\"",
> +            NULL,                               /* bug: rejected */
> +            "\"\\uC100\\uFFFF\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +            "\xFC\x84\x80\x80\x80\x80",
> +        },
> +        /* 2.2  Last possible sequence of a certain length */
> +        /* 2.2.1  1 byte U+007F */
> +        {
> +            "\"\x7F\"",
> +            "\x7F",
> +            "\"\177\"",
> +        },
> +        /* 2.2.2  2 bytes U+07FF */
> +        {
> +            "\"\xDF\xBF\"",
> +            "\xDF\xBF",
> +            "\"\\u07FF\"",
> +        },
> +        /* 2.2.3  3 bytes U+FFFF */
> +        {
> +            "\"\xEF\xBF\xBF\"",
> +            "\xEF\xBF\xBF",
> +            "\"\\uFFFF\"",
> +        },
> +        /* 2.2.4  4 bytes U+1FFFFF */
> +        {
> +            "\"\xF7\xBF\xBF\xBF\"",
> +            NULL,                 /* bug: rejected */
> +            "\"\\u7FFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +            "\xF7\xBF\xBF\xBF",
> +        },
> +        /* 2.2.5  5 bytes U+3FFFFFF */
> +        {
> +            "\"\xFB\xBF\xBF\xBF\xBF\"",
> +            NULL,                        /* bug: rejected */
> +            "\"\\uBFFF\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +            "\xFB\xBF\xBF\xBF\xBF",
> +        },
> +        /* 2.2.6  6 bytes U+7FFFFFFF */
> +        {
> +            "\"\xFD\xBF\xBF\xBF\xBF\xBF\"",
> +            NULL,                               /* bug: rejected */
> +            "\"\\uDFFF\\uFFFF\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +            "\xFD\xBF\xBF\xBF\xBF\xBF",
> +        },
> +        /* 2.3  Other boundary conditions */
> +        {
> +            /* U+D7FF */
> +            "\"\xED\x9F\xBF\"",
> +            "\xED\x9F\xBF",
> +            "\"\\uD7FF\"",
> +        },
> +        {
> +            /* U+E000 */
> +            "\"\xEE\x80\x80\"",
> +            "\xEE\x80\x80",
> +            "\"\\uE000\"",
> +        },
> +        {
> +            /* U+FFFD */
> +            "\"\xEF\xBF\xBD\"",
> +            "\xEF\xBF\xBD",
> +            "\"\\uFFFD\"",
> +        },
> +        {
> +            /* U+10FFFF */
> +            "\"\xF4\x8F\xBF\xBF\"",
> +            "\xF4\x8F\xBF\xBF",
> +            "\"\\u43FF\\uFFFF\"", /* bug: want "\"\\uDBFF\\uDFFF\"" */
> +        },
> +        {
> +            /* U+110000 */
> +            "\"\xF4\x90\x80\x80\"",
> +            "\xF4\x90\x80\x80",
> +            "\"\\u4400\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +        },
> +        /* 3  Malformed sequences */
> +        /* 3.1  Unexpected continuation bytes */
> +        /* 3.1.1  First continuation byte */
> +        {
> +            "\"\x80\"",
> +            "\x80",             /* bug: not corrected */
> +            "\"\\uFFFF\"",
> +        },
> +        /* 3.1.2  Last continuation byte */
> +        {
> +            "\"\xBF\"",
> +            "\xBF",             /* bug: not corrected */
> +            "\"\\uFFFF\"",
> +        },
> +        /* 3.1.3  2 continuation bytes */
> +        {
> +            "\"\x80\xBF\"",
> +            "\x80\xBF",         /* bug: not corrected */
> +            "\"\\uFFFF\\uFFFF\"",
> +        },
> +        /* 3.1.4  3 continuation bytes */
> +        {
> +            "\"\x80\xBF\x80\"",
> +            "\x80\xBF\x80",     /* bug: not corrected */
> +            "\"\\uFFFF\\uFFFF\\uFFFF\"",
> +        },
> +        /* 3.1.5  4 continuation bytes */
> +        {
> +            "\"\x80\xBF\x80\xBF\"",
> +            "\x80\xBF\x80\xBF", /* bug: not corrected */
> +            "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\"",
> +        },
> +        /* 3.1.6  5 continuation bytes */
> +        {
> +            "\"\x80\xBF\x80\xBF\x80\"",
> +            "\x80\xBF\x80\xBF\x80", /* bug: not corrected */
> +            "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\"",
> +        },
> +        /* 3.1.7  6 continuation bytes */
> +        {
> +            "\"\x80\xBF\x80\xBF\x80\xBF\"",
> +            "\x80\xBF\x80\xBF\x80\xBF", /* bug: not corrected */
> +            "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\"",
> +        },
> +        /* 3.1.8  7 continuation bytes */
> +        {
> +            "\"\x80\xBF\x80\xBF\x80\xBF\x80\"",
> +            "\x80\xBF\x80\xBF\x80\xBF\x80", /* bug: not corrected */
> +            "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\"",
> +        },
> +        /* 3.1.9  Sequence of all 64 possible continuation bytes */
> +        {
> +            "\"\x80\x81\x82\x83\x84\x85\x86\x87"
> +            "\x88\x89\x8A\x8B\x8C\x8D\x8E\x8F"
> +            "\x90\x91\x92\x93\x94\x95\x96\x97"
> +            "\x98\x99\x9A\x9B\x9C\x9D\x9E\x9F"
> +            "\xA0\xA1\xA2\xA3\xA4\xA5\xA6\xA7"
> +            "\xA8\xA9\xAA\xAB\xAC\xAD\xAE\xAF"
> +            "\xB0\xB1\xB2\xB3\xB4\xB5\xB6\xB7"
> +            "\xB8\xB9\xBA\xBB\xBC\xBD\xBE\xBF\"",
> +             /* bug: not corrected */
> +            "\x80\x81\x82\x83\x84\x85\x86\x87"
> +            "\x88\x89\x8A\x8B\x8C\x8D\x8E\x8F"
> +            "\x90\x91\x92\x93\x94\x95\x96\x97"
> +            "\x98\x99\x9A\x9B\x9C\x9D\x9E\x9F"
> +            "\xA0\xA1\xA2\xA3\xA4\xA5\xA6\xA7"
> +            "\xA8\xA9\xAA\xAB\xAC\xAD\xAE\xAF"
> +            "\xB0\xB1\xB2\xB3\xB4\xB5\xB6\xB7"
> +            "\xB8\xB9\xBA\xBB\xBC\xBD\xBE\xBF",
> +            "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
> +            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
> +            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
> +            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
> +            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
> +            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
> +            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
> +            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\""
> +        },
> +        /* 3.2  Lonely start characters */
> +        /* 3.2.1  All 32 first bytes of 2-byte sequences, followed by space */
> +        {
> +            "\"\xC0 \xC1 \xC2 \xC3 \xC4 \xC5 \xC6 \xC7 "
> +            "\xC8 \xC9 \xCA \xCB \xCC \xCD \xCE \xCF "
> +            "\xD0 \xD1 \xD2 \xD3 \xD4 \xD5 \xD6 \xD7 "
> +            "\xD8 \xD9 \xDA \xDB \xDC \xDD \xDE \xDF \"",
> +            NULL,               /* bug: rejected */
> +            "\"\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF "
> +            "\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF "
> +            "\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF "
> +            "\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \"",
> +            "\xC0 \xC1 \xC2 \xC3 \xC4 \xC5 \xC6 \xC7 "
> +            "\xC8 \xC9 \xCA \xCB \xCC \xCD \xCE \xCF "
> +            "\xD0 \xD1 \xD2 \xD3 \xD4 \xD5 \xD6 \xD7 "
> +            "\xD8 \xD9 \xDA \xDB \xDC \xDD \xDE \xDF ",
> +        },
> +        /* 3.2.2  All 16 first bytes of 3-byte sequences, followed by space */
> +        {
> +            "\"\xE0 \xE1 \xE2 \xE3 \xE4 \xE5 \xE6 \xE7 "
> +            "\xE8 \xE9 \xEA \xEB \xEC \xED \xEE \xEF \"",
> +            /* bug: not corrected */
> +            "\xE0 \xE1 \xE2 \xE3 \xE4 \xE5 \xE6 \xE7 "
> +            "\xE8 \xE9 \xEA \xEB \xEC \xED \xEE \xEF ",
> +            "\"\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF "
> +            "\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \"",
> +        },
> +        /* 3.2.3  All 8 first bytes of 4-byte sequences, followed by space */
> +        {
> +            "\"\xF0 \xF1 \xF2 \xF3 \xF4 \xF5 \xF6 \xF7 \"",
> +            NULL,               /* bug: rejected */
> +            "\"\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \"",
> +            "\xF0 \xF1 \xF2 \xF3 \xF4 \xF5 \xF6 \xF7 ",
> +        },
> +        /* 3.2.4  All 4 first bytes of 5-byte sequences, followed by space */
> +        {
> +            "\"\xF8 \xF9 \xFA \xFB \"",
> +            NULL,               /* bug: rejected */
> +            "\"\\uFFFF \\uFFFF \\uFFFF \\uFFFF \"",
> +            "\xF8 \xF9 \xFA \xFB ",
> +        },
> +        /* 3.2.5  All 2 first bytes of 6-byte sequences, followed by space */
> +        {
> +            "\"\xFC \xFD \"",
> +            NULL,               /* bug: rejected */
> +            "\"\\uFFFF \\uFFFF \"",
> +            "\xFC \xFD ",
> +        },
> +        /* 3.3  Sequences with last continuation byte missing */
> +        /* 3.3.1  2-byte sequence with last byte missing (U+0000) */
> +        {
> +            "\"\xC0\"",
> +            NULL,               /* bug: rejected */
> +            "\"\\uFFFF\"",
> +            "\xC0",
> +        },
> +        /* 3.3.2  3-byte sequence with last byte missing (U+0000) */
> +        {
> +            "\"\xE0\x80\"",
> +            "\xE0\x80",           /* bug: not corrected */
> +            "\"\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +        },
> +        /* 3.3.3  4-byte sequence with last byte missing (U+0000) */
> +        {
> +            "\"\xF0\x80\x80\"",
> +            "\xF0\x80\x80",     /* bug: not corrected */
> +            "\"\\u0000\"",      /* bug: want "\"\\uFFFF\"" */
> +        },
> +        /* 3.3.4  5-byte sequence with last byte missing (U+0000) */
> +        {
> +            /* invalid */
> +            "\"\xF8\x80\x80\x80\"", /* bug: not corrected */
> +            NULL,                   /* bug: rejected */
> +            "\"\\u8000\\uFFFF\"",   /* bug: want "\"\\uFFFF\"" */
> +            "\xF8\x80\x80\x80",
> +        },
> +        /* 3.3.5  6-byte sequence with last byte missing (U+0000) */
> +        {
> +            "\"\xFC\x80\x80\x80\x80\"",
> +            NULL,                        /* bug: rejected */
> +            "\"\\uC000\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +            "\xFC\x80\x80\x80\x80",
> +        },
> +        /* 3.3.6  2-byte sequence with last byte missing (U+07FF) */
> +        {
> +            "\"\xDF\"",
> +            "\xDF",             /* bug: not corrected */
> +            "\"\\uFFFF\"",
> +        },
> +        /* 3.3.7  3-byte sequence with last byte missing (U+FFFF) */
> +        {
> +            "\"\xEF\xBF\"",
> +            "\xEF\xBF",           /* bug: not corrected */
> +            "\"\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +        },
> +        /* 3.3.8  4-byte sequence with last byte missing (U+1FFFFF) */
> +        {
> +            "\"\xF7\xBF\xBF\"",
> +            NULL,               /* bug: rejected */
> +            "\"\\u7FFF\"",      /* bug: want "\"\\uFFFF\"" */
> +            "\xF7\xBF\xBF",
> +        },
> +        /* 3.3.9  5-byte sequence with last byte missing (U+3FFFFFF) */
> +        {
> +            "\"\xFB\xBF\xBF\xBF\"",
> +            NULL,                 /* bug: rejected */
> +            "\"\\uBFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +            "\xFB\xBF\xBF\xBF",
> +        },
> +        /* 3.3.10  6-byte sequence with last byte missing (U+7FFFFFFF) */
> +        {
> +            "\"\xFD\xBF\xBF\xBF\xBF\"",
> +            NULL,                        /* bug: rejected */
> +            "\"\\uDFFF\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"", */
> +            "\xFD\xBF\xBF\xBF\xBF",
> +        },
> +        /* 3.4  Concatenation of incomplete sequences */
> +        {
> +            "\"\xC0\xE0\x80\xF0\x80\x80\xF8\x80\x80\x80\xFC\x80\x80\x80\x80"
> +            "\xDF\xEF\xBF\xF7\xBF\xBF\xFB\xBF\xBF\xBF\xFD\xBF\xBF\xBF\xBF\"",
> +            NULL,               /* bug: rejected */
> +            /* bug: want "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
> +               "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\"" */
> +            "\"\\u0020\\uFFFF\\u0000\\u8000\\uFFFF\\uC000\\uFFFF\\uFFFF"
> +            "\\u07EF\\uFFFF\\u7FFF\\uBFFF\\uFFFF\\uDFFF\\uFFFF\\uFFFF\"",
> +            "\xC0\xE0\x80\xF0\x80\x80\xF8\x80\x80\x80\xFC\x80\x80\x80\x80"
> +            "\xDF\xEF\xBF\xF7\xBF\xBF\xFB\xBF\xBF\xBF\xFD\xBF\xBF\xBF\xBF",
> +        },
> +        /* 3.5  Impossible bytes */
> +        {
> +            "\"\xFE\"",
> +            NULL,               /* bug: rejected */
> +            "\"\\uFFFF\"",
> +            "\xFE",
> +        },
> +        {
> +            "\"\xFF\"",
> +            NULL,               /* bug: rejected */
> +            "\"\\uFFFF\"",
> +            "\xFF",
> +        },
> +        {
> +            "\"\xFE\xFE\xFF\xFF\"",
> +            NULL,                 /* bug: rejected */
> +            /* bug: want "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\"" */
> +            "\"\\uEFBF\\uFFFF\"",
> +            "\xFE\xFE\xFF\xFF",
> +        },
> +        /* 4  Overlong sequences */
> +        /* 4.1  Overlong '/' */
> +        {
> +            "\"\xC0\xAF\"",
> +            NULL,               /* bug: rejected */
> +            "\"\\u002F\"",      /* bug: want "\"/\"" */
> +            "\xC0\xAF",
> +        },
> +        {
> +            "\"\xE0\x80\xAF\"",
> +            "\xE0\x80\xAF",     /* bug: not corrected */
> +            "\"\\u002F\"",      /* bug: want "\"/\"" */
> +        },
> +        {
> +            "\"\xF0\x80\x80\xAF\"",
> +            "\xF0\x80\x80\xAF",  /* bug: not corrected */
> +            "\"\\u0000\\uFFFF\"" /* bug: want "\"/\"" */
> +        },
> +        {
> +            "\"\xF8\x80\x80\x80\xAF\"",
> +            NULL,                        /* bug: rejected */
> +            "\"\\u8000\\uFFFF\\uFFFF\"", /* bug: want "\"/\"" */
> +            "\xF8\x80\x80\x80\xAF",
> +        },
> +        {
> +            "\"\xFC\x80\x80\x80\x80\xAF\"",
> +            NULL,                               /* bug: rejected */
> +            "\"\\uC000\\uFFFF\\uFFFF\\uFFFF\"", /* bug: want "\"/\"" */
> +            "\xFC\x80\x80\x80\x80\xAF",
> +        },
> +        /* 4.2  Maximum overlong sequences */
> +        {
> +            /* \U+007F */
> +            "\"\xC1\xBF\"",
> +            NULL,               /* bug: rejected */
> +            "\"\\u007F\"",      /* bug: want "\"\177\"" */
> +            "\xC1\xBF",
> +        },
> +        {
> +            /* \U+07FF */
> +            "\"\xE0\x9F\xBF\"",
> +            "\xE0\x9F\xBF",     /* bug: not corrected */
> +            "\"\\u07FF\"",
> +        },
> +        {
> +            /* \U+FFFF */
> +            "\"\xF0\x8F\xBF\xBF\"",
> +            "\xF0\x8F\xBF\xBF",   /* bug: not corrected */
> +            "\"\\u03FF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+1FFFFF */
> +            "\"\xF8\x87\xBF\xBF\xBF\"",
> +            NULL,                        /* bug: rejected */
> +            "\"\\u81FF\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +            "\xF8\x87\xBF\xBF\xBF",
> +        },
> +        {
> +            /* \U+3FFFFFF */
> +            "\"\xFC\x83\xBF\xBF\xBF\xBF\"",
> +            NULL,                               /* bug: rejected */
> +            "\"\\uC0FF\\uFFFF\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
> +            "\xFC\x83\xBF\xBF\xBF\xBF",
> +        },
> +        /* 4.3  Overlong representation of the NUL character */
> +        {
> +            /* \U+0000 */
> +            "\"\xC0\x80\"",
> +            NULL,               /* bug: rejected */
> +            "\"\\u0000\"",
> +            "\xC0\x80",
> +        },
> +        {
> +            /* \U+0000 */
> +            "\"\xE0\x80\x80\"",
> +            "\xE0\x80\x80",     /* bug: not corrected */
> +            "\"\\u0000\"",
> +        },
> +        {
> +            /* \U+0000 */
> +            "\"\xF0\x80\x80\x80\"",
> +            "\xF0\x80\x80\x80",   /* bug: not corrected */
> +            "\"\\u0000\\uFFFF\"", /* bug: want "\"\\u0000\"" */
> +        },
> +        {
> +            /* \U+0000 */
> +            "\"\xF8\x80\x80\x80\x80\"",
> +            NULL,                        /* bug: rejected */
> +            "\"\\u8000\\uFFFF\\uFFFF\"", /* bug: want "\"\\u0000\"" */
> +            "\xF8\x80\x80\x80\x80",
> +        },
> +        {
> +            /* \U+0000 */
> +            "\"\xFC\x80\x80\x80\x80\x80\"",
> +            NULL,                               /* bug: rejected */
> +            "\"\\uC000\\uFFFF\\uFFFF\\uFFFF\"", /* bug: want "\"\\u0000\"" */
> +            "\xFC\x80\x80\x80\x80\x80",
> +        },
> +        /* 5  Illegal code positions */
> +        /* 5.1  Single UTF-16 surrogates */
> +        {
> +            /* \U+D800 */
> +            "\"\xED\xA0\x80\"",
> +            "\xED\xA0\x80",     /* bug: not corrected */
> +            "\"\\uD800\"",      /* bug: want "\"\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+DB7F */
> +            "\"\xED\xAD\xBF\"",
> +            "\xED\xAD\xBF",     /* bug: not corrected */
> +            "\"\\uDB7F\"",      /* bug: want "\"\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+DB80 */
> +            "\"\xED\xAE\x80\"",
> +            "\xED\xAE\x80",     /* bug: not corrected */
> +            "\"\\uDB80\"",      /* bug: want "\"\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+DBFF */
> +            "\"\xED\xAF\xBF\"",
> +            "\xED\xAF\xBF",     /* bug: not corrected */
> +            "\"\\uDBFF\"",      /* bug: want "\"\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+DC00 */
> +            "\"\xED\xB0\x80\"",
> +            "\xED\xB0\x80",     /* bug: not corrected */
> +            "\"\\uDC00\"",      /* bug: want "\"\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+DF80 */
> +            "\"\xED\xBE\x80\"",
> +            "\xED\xBE\x80",     /* bug: not corrected */
> +            "\"\\uDF80\"",      /* bug: want "\"\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+DFFF */
> +            "\"\xED\xBF\xBF\"",
> +            "\xED\xBF\xBF",     /* bug: not corrected */
> +            "\"\\uDFFF\"",      /* bug: want "\"\\uFFFF\"" */
> +        },
> +        /* 5.2  Paired UTF-16 surrogates */
> +        {
> +            /* \U+D800\U+DC00 */
> +            "\"\xED\xA0\x80\xED\xB0\x80\"",
> +            "\xED\xA0\x80\xED\xB0\x80", /* bug: not corrected */
> +            "\"\\uD800\\uDC00\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+D800\U+DFFF */
> +            "\"\xED\xA0\x80\xED\xBF\xBF\"",
> +            "\xED\xA0\x80\xED\xBF\xBF", /* bug: not corrected */
> +            "\"\\uD800\\uDFFF\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+DB7F\U+DC00 */
> +            "\"\xED\xAD\xBF\xED\xB0\x80\"",
> +            "\xED\xAD\xBF\xED\xB0\x80", /* bug: not corrected */
> +            "\"\\uDB7F\\uDC00\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+DB7F\U+DFFF */
> +            "\"\xED\xAD\xBF\xED\xBF\xBF\"",
> +            "\xED\xAD\xBF\xED\xBF\xBF", /* bug: not corrected */
> +            "\"\\uDB7F\\uDFFF\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+DB80\U+DC00 */
> +            "\"\xED\xAE\x80\xED\xB0\x80\"",
> +            "\xED\xAE\x80\xED\xB0\x80", /* bug: not corrected */
> +            "\"\\uDB80\\uDC00\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+DB80\U+DFFF */
> +            "\"\xED\xAE\x80\xED\xBF\xBF\"",
> +            "\xED\xAE\x80\xED\xBF\xBF", /* bug: not corrected */
> +            "\"\\uDB80\\uDFFF\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+DBFF\U+DC00 */
> +            "\"\xED\xAF\xBF\xED\xB0\x80\"",
> +            "\xED\xAF\xBF\xED\xB0\x80", /* bug: not corrected */
> +            "\"\\uDBFF\\uDC00\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
> +        },
> +        {
> +            /* \U+DBFF\U+DFFF */
> +            "\"\xED\xAF\xBF\xED\xBF\xBF\"",
> +            "\xED\xAF\xBF\xED\xBF\xBF", /* bug: not corrected */
> +            "\"\\uDBFF\\uDFFF\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
> +        },
> +        /* 5.3  Other illegal code positions */
> +        {
> +            /* \U+FFFE */
> +            "\"\xEF\xBF\xBE\"",
> +            "\xEF\xBF\xBE",     /* bug: not corrected */
> +            "\"\\uFFFE\"",      /* bug: not corrected */
> +        },
> +        {
> +            /* \U+FFFF */
> +            "\"\xEF\xBF\xBF\"",
> +            "\xEF\xBF\xBF",     /* bug: not corrected */
> +            "\"\\uFFFF\"",      /* bug: not corrected */
> +        },
> +        {}
> +    };
> +    int i;
> +    QObject *obj;
> +    QString *str;
> +    const char *json_in, *utf8_out, *utf8_in, *json_out;
> +
> +    for (i = 0; test_cases[i].json_in; i++) {
> +        json_in = test_cases[i].json_in;
> +        utf8_out = test_cases[i].utf8_out;
> +        utf8_in = test_cases[i].utf8_in ?: test_cases[i].utf8_out;
> +        json_out = test_cases[i].json_out ?: test_cases[i].json_in;
> +
> +        obj = qobject_from_json(json_in);
> +        if (utf8_out) {
> +            g_assert(obj);
> +            g_assert(qobject_type(obj) == QTYPE_QSTRING);
> +            str = qobject_to_qstring(obj);
> +            g_assert_cmpstr(qstring_get_str(str), ==, utf8_out);
> +        } else {
> +            g_assert(!obj);
> +        }
> +        qobject_decref(obj);
> +
> +        obj = QOBJECT(qstring_from_str(utf8_in));
> +        str = qobject_to_json(obj);
> +        if (json_out) {
> +            g_assert(str);
> +            g_assert_cmpstr(qstring_get_str(str), ==, json_out);
> +        } else {
> +            g_assert(!str);
> +        }
> +        QDECREF(str);
> +        qobject_decref(obj);
> +
> +        /*
> +         * Disabled, because json_out currently contains the crap
> +         * qobject_to_json() produces.
> +         * FIXME Enable once these bugs have been fixed.
> +         */
> +        if (0 && json_out != json_in) {
> +            obj = qobject_from_json(json_out);
> +            g_assert(obj);
> +            g_assert(qobject_type(obj) == QTYPE_QSTRING);
> +            str = qobject_to_qstring(obj);
> +            g_assert_cmpstr(qstring_get_str(str), ==, utf8_out);
> +        }
> +    }
> +}
> +
>  static void vararg_string(void)
>  {
>      int i;
> @@ -748,6 +1411,7 @@ int main(int argc, char **argv)
>  
>      g_test_add_func("/literals/string/simple", simple_string);
>      g_test_add_func("/literals/string/escaped", escaped_string);
> +    g_test_add_func("/literals/string/utf8", utf8_string);
>      g_test_add_func("/literals/string/single_quote", single_quote_string);
>      g_test_add_func("/literals/string/vararg", vararg_string);
>

Patch

diff --git a/tests/check-qjson.c b/tests/check-qjson.c
index 32ffb43..ec85a0c 100644
--- a/tests/check-qjson.c
+++ b/tests/check-qjson.c
@@ -1,8 +1,10 @@ 
 /*
  * Copyright IBM, Corp. 2009
+ * Copyright (c) 2013 Red Hat Inc.
  *
  * Authors:
  *  Anthony Liguori   <aliguori@us.ibm.com>
+ *  Markus Armbruster <armbru@redhat.com>,
  *
  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
  * See the COPYING.LIB file in the top-level directory.
@@ -131,6 +133,667 @@  static void single_quote_string(void)
     }
 }
 
+static void utf8_string(void)
+{
+    /*
+     * FIXME Current behavior for invalid UTF-8 sequences is
+     * incorrect.  This test expects current, incorrect results.
+     * They're all marked "bug:" below, and are to be replaced by
+     * correct ones as the bugs get fixed.
+     *
+     * The JSON parser rejects some invalid sequences, but accepts
+     * others without correcting the problem.
+     *
+     * The JSON formatter replaces some invalid sequences by U+FFFF (a
+     * noncharacter), and goes wonky for others.
+     *
+     * For both directions, we should either reject all invalid
+     * sequences, or minimize overlong sequences and replace all other
+     * invalid sequences by a suitable replacement character.  A
+     * common choice for replacement is U+FFFD.
+     *
+     * Problem: we can't easily deal with embedded U+0000.  Parsing
+     * the JSON string "this \\u0000" is fun" yields "this \0 is fun",
+     * which gets misinterpreted as NUL-terminated "this ".  We should
+     * consider using overlong encoding \xC0\x80 for U+0000 ("modified
+     * UTF-8").
+     *
+     * Test cases are scraped from Markus Kuhn's UTF-8 decoder
+     * capability and stress test at
+     * http://www.cl.cam.ac.uk/~mgk25/ucs/examples/UTF-8-test.txt
+     */
+    static const struct {
+        const char *json_in;
+        const char *utf8_out;
+        const char *json_out;   /* defaults to @json_in */
+        const char *utf8_in;    /* defaults to @utf8_out */
+    } test_cases[] = {
+        /*
+         * Bug markers used here:
+         * - bug: not corrected
+         *   JSON parser fails to correct invalid sequence(s)
+         * - bug: rejected
+         *   JSON parser rejects invalid sequence(s)
+         *   We may choose to define this as feature
+         * - bug: want "\"...\""
+         *   JSON formatter produces incorrect result, this is the
+         *   correct one, assuming replacement character U+FFFF
+         * - bug: want "..." (no \")
+         *   JSON parser produces incorrect result, this is the
+         *   correct one, assuming replacement character U+FFFF
+         *   We may choose to reject instead of replace
+         * Not marked explicitly, but trivial to find:
+         * - JSON formatter replacing invalid sequence by \\uFFFF is a
+         *   bug if we want it to fail for invalid sequences.
+         */
+
+        /* 1  Some correct UTF-8 text */
+        {
+            /* a bit of German */
+            "\"Falsches \xC3\x9C" "ben von Xylophonmusik qu\xC3\xA4lt"
+            " jeden gr\xC3\xB6\xC3\x9F" "eren Zwerg.\"",
+            "Falsches \xC3\x9C" "ben von Xylophonmusik qu\xC3\xA4lt"
+            " jeden gr\xC3\xB6\xC3\x9F" "eren Zwerg.",
+            "\"Falsches \\u00DCben von Xylophonmusik qu\\u00E4lt"
+            " jeden gr\\u00F6\\u00DFeren Zwerg.\"",
+        },
+        {
+            /* a bit of Greek */
+            "\"\xCE\xBA\xE1\xBD\xB9\xCF\x83\xCE\xBC\xCE\xB5\"",
+            "\xCE\xBA\xE1\xBD\xB9\xCF\x83\xCE\xBC\xCE\xB5",
+            "\"\\u03BA\\u1F79\\u03C3\\u03BC\\u03B5\"",
+        },
+        /* 2  Boundary condition test cases */
+        /* 2.1  First possible sequence of a certain length */
+        /* 2.1.1  1 byte U+0000 */
+        {
+            "\"\\u0000\"",
+            "",                 /* bug: want overlong "\xC0\x80" */
+            "\"\"",             /* bug: want "\"\\u0000\"" */
+        },
+        /* 2.1.2  2 bytes U+0080 */
+        {
+            "\"\xC2\x80\"",
+            "\xC2\x80",
+            "\"\\u0080\"",
+        },
+        /* 2.1.3  3 bytes U+0800 */
+        {
+            "\"\xE0\xA0\x80\"",
+            "\xE0\xA0\x80",
+            "\"\\u0800\"",
+        },
+        /* 2.1.4  4 bytes U+10000 */
+        {
+            "\"\xF0\x90\x80\x80\"",
+            "\xF0\x90\x80\x80",
+            "\"\\u0400\\uFFFF\"", /* bug: want "\"\\uD800\\uDC00\"" */
+        },
+        /* 2.1.5  5 bytes U+200000 */
+        {
+            "\"\xF8\x88\x80\x80\x80\"",
+            NULL,                        /* bug: rejected */
+            "\"\\u8200\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+            "\xF8\x88\x80\x80\x80",
+        },
+        /* 2.1.6  6 bytes U+4000000 */
+        {
+            "\"\xFC\x84\x80\x80\x80\x80\"",
+            NULL,                               /* bug: rejected */
+            "\"\\uC100\\uFFFF\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+            "\xFC\x84\x80\x80\x80\x80",
+        },
+        /* 2.2  Last possible sequence of a certain length */
+        /* 2.2.1  1 byte U+007F */
+        {
+            "\"\x7F\"",
+            "\x7F",
+            "\"\177\"",
+        },
+        /* 2.2.2  2 bytes U+07FF */
+        {
+            "\"\xDF\xBF\"",
+            "\xDF\xBF",
+            "\"\\u07FF\"",
+        },
+        /* 2.2.3  3 bytes U+FFFF */
+        {
+            "\"\xEF\xBF\xBF\"",
+            "\xEF\xBF\xBF",
+            "\"\\uFFFF\"",
+        },
+        /* 2.2.4  4 bytes U+1FFFFF */
+        {
+            "\"\xF7\xBF\xBF\xBF\"",
+            NULL,                 /* bug: rejected */
+            "\"\\u7FFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+            "\xF7\xBF\xBF\xBF",
+        },
+        /* 2.2.5  5 bytes U+3FFFFFF */
+        {
+            "\"\xFB\xBF\xBF\xBF\xBF\"",
+            NULL,                        /* bug: rejected */
+            "\"\\uBFFF\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+            "\xFB\xBF\xBF\xBF\xBF",
+        },
+        /* 2.2.6  6 bytes U+7FFFFFFF */
+        {
+            "\"\xFD\xBF\xBF\xBF\xBF\xBF\"",
+            NULL,                               /* bug: rejected */
+            "\"\\uDFFF\\uFFFF\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+            "\xFD\xBF\xBF\xBF\xBF\xBF",
+        },
+        /* 2.3  Other boundary conditions */
+        {
+            /* U+D7FF */
+            "\"\xED\x9F\xBF\"",
+            "\xED\x9F\xBF",
+            "\"\\uD7FF\"",
+        },
+        {
+            /* U+E000 */
+            "\"\xEE\x80\x80\"",
+            "\xEE\x80\x80",
+            "\"\\uE000\"",
+        },
+        {
+            /* U+FFFD */
+            "\"\xEF\xBF\xBD\"",
+            "\xEF\xBF\xBD",
+            "\"\\uFFFD\"",
+        },
+        {
+            /* U+10FFFF */
+            "\"\xF4\x8F\xBF\xBF\"",
+            "\xF4\x8F\xBF\xBF",
+            "\"\\u43FF\\uFFFF\"", /* bug: want "\"\\uDBFF\\uDFFF\"" */
+        },
+        {
+            /* U+110000 */
+            "\"\xF4\x90\x80\x80\"",
+            "\xF4\x90\x80\x80",
+            "\"\\u4400\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+        },
+        /* 3  Malformed sequences */
+        /* 3.1  Unexpected continuation bytes */
+        /* 3.1.1  First continuation byte */
+        {
+            "\"\x80\"",
+            "\x80",             /* bug: not corrected */
+            "\"\\uFFFF\"",
+        },
+        /* 3.1.2  Last continuation byte */
+        {
+            "\"\xBF\"",
+            "\xBF",             /* bug: not corrected */
+            "\"\\uFFFF\"",
+        },
+        /* 3.1.3  2 continuation bytes */
+        {
+            "\"\x80\xBF\"",
+            "\x80\xBF",         /* bug: not corrected */
+            "\"\\uFFFF\\uFFFF\"",
+        },
+        /* 3.1.4  3 continuation bytes */
+        {
+            "\"\x80\xBF\x80\"",
+            "\x80\xBF\x80",     /* bug: not corrected */
+            "\"\\uFFFF\\uFFFF\\uFFFF\"",
+        },
+        /* 3.1.5  4 continuation bytes */
+        {
+            "\"\x80\xBF\x80\xBF\"",
+            "\x80\xBF\x80\xBF", /* bug: not corrected */
+            "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\"",
+        },
+        /* 3.1.6  5 continuation bytes */
+        {
+            "\"\x80\xBF\x80\xBF\x80\"",
+            "\x80\xBF\x80\xBF\x80", /* bug: not corrected */
+            "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\"",
+        },
+        /* 3.1.7  6 continuation bytes */
+        {
+            "\"\x80\xBF\x80\xBF\x80\xBF\"",
+            "\x80\xBF\x80\xBF\x80\xBF", /* bug: not corrected */
+            "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\"",
+        },
+        /* 3.1.8  7 continuation bytes */
+        {
+            "\"\x80\xBF\x80\xBF\x80\xBF\x80\"",
+            "\x80\xBF\x80\xBF\x80\xBF\x80", /* bug: not corrected */
+            "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\"",
+        },
+        /* 3.1.9  Sequence of all 64 possible continuation bytes */
+        {
+            "\"\x80\x81\x82\x83\x84\x85\x86\x87"
+            "\x88\x89\x8A\x8B\x8C\x8D\x8E\x8F"
+            "\x90\x91\x92\x93\x94\x95\x96\x97"
+            "\x98\x99\x9A\x9B\x9C\x9D\x9E\x9F"
+            "\xA0\xA1\xA2\xA3\xA4\xA5\xA6\xA7"
+            "\xA8\xA9\xAA\xAB\xAC\xAD\xAE\xAF"
+            "\xB0\xB1\xB2\xB3\xB4\xB5\xB6\xB7"
+            "\xB8\xB9\xBA\xBB\xBC\xBD\xBE\xBF\"",
+             /* bug: not corrected */
+            "\x80\x81\x82\x83\x84\x85\x86\x87"
+            "\x88\x89\x8A\x8B\x8C\x8D\x8E\x8F"
+            "\x90\x91\x92\x93\x94\x95\x96\x97"
+            "\x98\x99\x9A\x9B\x9C\x9D\x9E\x9F"
+            "\xA0\xA1\xA2\xA3\xA4\xA5\xA6\xA7"
+            "\xA8\xA9\xAA\xAB\xAC\xAD\xAE\xAF"
+            "\xB0\xB1\xB2\xB3\xB4\xB5\xB6\xB7"
+            "\xB8\xB9\xBA\xBB\xBC\xBD\xBE\xBF",
+            "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
+            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
+            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
+            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
+            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
+            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
+            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
+            "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\""
+        },
+        /* 3.2  Lonely start characters */
+        /* 3.2.1  All 32 first bytes of 2-byte sequences, followed by space */
+        {
+            "\"\xC0 \xC1 \xC2 \xC3 \xC4 \xC5 \xC6 \xC7 "
+            "\xC8 \xC9 \xCA \xCB \xCC \xCD \xCE \xCF "
+            "\xD0 \xD1 \xD2 \xD3 \xD4 \xD5 \xD6 \xD7 "
+            "\xD8 \xD9 \xDA \xDB \xDC \xDD \xDE \xDF \"",
+            NULL,               /* bug: rejected */
+            "\"\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF "
+            "\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF "
+            "\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF "
+            "\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \"",
+            "\xC0 \xC1 \xC2 \xC3 \xC4 \xC5 \xC6 \xC7 "
+            "\xC8 \xC9 \xCA \xCB \xCC \xCD \xCE \xCF "
+            "\xD0 \xD1 \xD2 \xD3 \xD4 \xD5 \xD6 \xD7 "
+            "\xD8 \xD9 \xDA \xDB \xDC \xDD \xDE \xDF ",
+        },
+        /* 3.2.2  All 16 first bytes of 3-byte sequences, followed by space */
+        {
+            "\"\xE0 \xE1 \xE2 \xE3 \xE4 \xE5 \xE6 \xE7 "
+            "\xE8 \xE9 \xEA \xEB \xEC \xED \xEE \xEF \"",
+            /* bug: not corrected */
+            "\xE0 \xE1 \xE2 \xE3 \xE4 \xE5 \xE6 \xE7 "
+            "\xE8 \xE9 \xEA \xEB \xEC \xED \xEE \xEF ",
+            "\"\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF "
+            "\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \"",
+        },
+        /* 3.2.3  All 8 first bytes of 4-byte sequences, followed by space */
+        {
+            "\"\xF0 \xF1 \xF2 \xF3 \xF4 \xF5 \xF6 \xF7 \"",
+            NULL,               /* bug: rejected */
+            "\"\\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \\uFFFF \"",
+            "\xF0 \xF1 \xF2 \xF3 \xF4 \xF5 \xF6 \xF7 ",
+        },
+        /* 3.2.4  All 4 first bytes of 5-byte sequences, followed by space */
+        {
+            "\"\xF8 \xF9 \xFA \xFB \"",
+            NULL,               /* bug: rejected */
+            "\"\\uFFFF \\uFFFF \\uFFFF \\uFFFF \"",
+            "\xF8 \xF9 \xFA \xFB ",
+        },
+        /* 3.2.5  All 2 first bytes of 6-byte sequences, followed by space */
+        {
+            "\"\xFC \xFD \"",
+            NULL,               /* bug: rejected */
+            "\"\\uFFFF \\uFFFF \"",
+            "\xFC \xFD ",
+        },
+        /* 3.3  Sequences with last continuation byte missing */
+        /* 3.3.1  2-byte sequence with last byte missing (U+0000) */
+        {
+            "\"\xC0\"",
+            NULL,               /* bug: rejected */
+            "\"\\uFFFF\"",
+            "\xC0",
+        },
+        /* 3.3.2  3-byte sequence with last byte missing (U+0000) */
+        {
+            "\"\xE0\x80\"",
+            "\xE0\x80",           /* bug: not corrected */
+            "\"\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+        },
+        /* 3.3.3  4-byte sequence with last byte missing (U+0000) */
+        {
+            "\"\xF0\x80\x80\"",
+            "\xF0\x80\x80",     /* bug: not corrected */
+            "\"\\u0000\"",      /* bug: want "\"\\uFFFF\"" */
+        },
+        /* 3.3.4  5-byte sequence with last byte missing (U+0000) */
+        {
+            /* invalid */
+            "\"\xF8\x80\x80\x80\"", /* bug: not corrected */
+            NULL,                   /* bug: rejected */
+            "\"\\u8000\\uFFFF\"",   /* bug: want "\"\\uFFFF\"" */
+            "\xF8\x80\x80\x80",
+        },
+        /* 3.3.5  6-byte sequence with last byte missing (U+0000) */
+        {
+            "\"\xFC\x80\x80\x80\x80\"",
+            NULL,                        /* bug: rejected */
+            "\"\\uC000\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+            "\xFC\x80\x80\x80\x80",
+        },
+        /* 3.3.6  2-byte sequence with last byte missing (U+07FF) */
+        {
+            "\"\xDF\"",
+            "\xDF",             /* bug: not corrected */
+            "\"\\uFFFF\"",
+        },
+        /* 3.3.7  3-byte sequence with last byte missing (U+FFFF) */
+        {
+            "\"\xEF\xBF\"",
+            "\xEF\xBF",           /* bug: not corrected */
+            "\"\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+        },
+        /* 3.3.8  4-byte sequence with last byte missing (U+1FFFFF) */
+        {
+            "\"\xF7\xBF\xBF\"",
+            NULL,               /* bug: rejected */
+            "\"\\u7FFF\"",      /* bug: want "\"\\uFFFF\"" */
+            "\xF7\xBF\xBF",
+        },
+        /* 3.3.9  5-byte sequence with last byte missing (U+3FFFFFF) */
+        {
+            "\"\xFB\xBF\xBF\xBF\"",
+            NULL,                 /* bug: rejected */
+            "\"\\uBFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+            "\xFB\xBF\xBF\xBF",
+        },
+        /* 3.3.10  6-byte sequence with last byte missing (U+7FFFFFFF) */
+        {
+            "\"\xFD\xBF\xBF\xBF\xBF\"",
+            NULL,                        /* bug: rejected */
+            "\"\\uDFFF\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"", */
+            "\xFD\xBF\xBF\xBF\xBF",
+        },
+        /* 3.4  Concatenation of incomplete sequences */
+        {
+            "\"\xC0\xE0\x80\xF0\x80\x80\xF8\x80\x80\x80\xFC\x80\x80\x80\x80"
+            "\xDF\xEF\xBF\xF7\xBF\xBF\xFB\xBF\xBF\xBF\xFD\xBF\xBF\xBF\xBF\"",
+            NULL,               /* bug: rejected */
+            /* bug: want "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF"
+               "\\uFFFF\\uFFFF\\uFFFF\\uFFFF\\uFFFF\"" */
+            "\"\\u0020\\uFFFF\\u0000\\u8000\\uFFFF\\uC000\\uFFFF\\uFFFF"
+            "\\u07EF\\uFFFF\\u7FFF\\uBFFF\\uFFFF\\uDFFF\\uFFFF\\uFFFF\"",
+            "\xC0\xE0\x80\xF0\x80\x80\xF8\x80\x80\x80\xFC\x80\x80\x80\x80"
+            "\xDF\xEF\xBF\xF7\xBF\xBF\xFB\xBF\xBF\xBF\xFD\xBF\xBF\xBF\xBF",
+        },
+        /* 3.5  Impossible bytes */
+        {
+            "\"\xFE\"",
+            NULL,               /* bug: rejected */
+            "\"\\uFFFF\"",
+            "\xFE",
+        },
+        {
+            "\"\xFF\"",
+            NULL,               /* bug: rejected */
+            "\"\\uFFFF\"",
+            "\xFF",
+        },
+        {
+            "\"\xFE\xFE\xFF\xFF\"",
+            NULL,                 /* bug: rejected */
+            /* bug: want "\"\\uFFFF\\uFFFF\\uFFFF\\uFFFF\"" */
+            "\"\\uEFBF\\uFFFF\"",
+            "\xFE\xFE\xFF\xFF",
+        },
+        /* 4  Overlong sequences */
+        /* 4.1  Overlong '/' */
+        {
+            "\"\xC0\xAF\"",
+            NULL,               /* bug: rejected */
+            "\"\\u002F\"",      /* bug: want "\"/\"" */
+            "\xC0\xAF",
+        },
+        {
+            "\"\xE0\x80\xAF\"",
+            "\xE0\x80\xAF",     /* bug: not corrected */
+            "\"\\u002F\"",      /* bug: want "\"/\"" */
+        },
+        {
+            "\"\xF0\x80\x80\xAF\"",
+            "\xF0\x80\x80\xAF",  /* bug: not corrected */
+            "\"\\u0000\\uFFFF\"" /* bug: want "\"/\"" */
+        },
+        {
+            "\"\xF8\x80\x80\x80\xAF\"",
+            NULL,                        /* bug: rejected */
+            "\"\\u8000\\uFFFF\\uFFFF\"", /* bug: want "\"/\"" */
+            "\xF8\x80\x80\x80\xAF",
+        },
+        {
+            "\"\xFC\x80\x80\x80\x80\xAF\"",
+            NULL,                               /* bug: rejected */
+            "\"\\uC000\\uFFFF\\uFFFF\\uFFFF\"", /* bug: want "\"/\"" */
+            "\xFC\x80\x80\x80\x80\xAF",
+        },
+        /* 4.2  Maximum overlong sequences */
+        {
+            /* \U+007F */
+            "\"\xC1\xBF\"",
+            NULL,               /* bug: rejected */
+            "\"\\u007F\"",      /* bug: want "\"\177\"" */
+            "\xC1\xBF",
+        },
+        {
+            /* \U+07FF */
+            "\"\xE0\x9F\xBF\"",
+            "\xE0\x9F\xBF",     /* bug: not corrected */
+            "\"\\u07FF\"",
+        },
+        {
+            /* \U+FFFF */
+            "\"\xF0\x8F\xBF\xBF\"",
+            "\xF0\x8F\xBF\xBF",   /* bug: not corrected */
+            "\"\\u03FF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+        },
+        {
+            /* \U+1FFFFF */
+            "\"\xF8\x87\xBF\xBF\xBF\"",
+            NULL,                        /* bug: rejected */
+            "\"\\u81FF\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+            "\xF8\x87\xBF\xBF\xBF",
+        },
+        {
+            /* \U+3FFFFFF */
+            "\"\xFC\x83\xBF\xBF\xBF\xBF\"",
+            NULL,                               /* bug: rejected */
+            "\"\\uC0FF\\uFFFF\\uFFFF\\uFFFF\"", /* bug: want "\"\\uFFFF\"" */
+            "\xFC\x83\xBF\xBF\xBF\xBF",
+        },
+        /* 4.3  Overlong representation of the NUL character */
+        {
+            /* \U+0000 */
+            "\"\xC0\x80\"",
+            NULL,               /* bug: rejected */
+            "\"\\u0000\"",
+            "\xC0\x80",
+        },
+        {
+            /* \U+0000 */
+            "\"\xE0\x80\x80\"",
+            "\xE0\x80\x80",     /* bug: not corrected */
+            "\"\\u0000\"",
+        },
+        {
+            /* \U+0000 */
+            "\"\xF0\x80\x80\x80\"",
+            "\xF0\x80\x80\x80",   /* bug: not corrected */
+            "\"\\u0000\\uFFFF\"", /* bug: want "\"\\u0000\"" */
+        },
+        {
+            /* \U+0000 */
+            "\"\xF8\x80\x80\x80\x80\"",
+            NULL,                        /* bug: rejected */
+            "\"\\u8000\\uFFFF\\uFFFF\"", /* bug: want "\"\\u0000\"" */
+            "\xF8\x80\x80\x80\x80",
+        },
+        {
+            /* \U+0000 */
+            "\"\xFC\x80\x80\x80\x80\x80\"",
+            NULL,                               /* bug: rejected */
+            "\"\\uC000\\uFFFF\\uFFFF\\uFFFF\"", /* bug: want "\"\\u0000\"" */
+            "\xFC\x80\x80\x80\x80\x80",
+        },
+        /* 5  Illegal code positions */
+        /* 5.1  Single UTF-16 surrogates */
+        {
+            /* \U+D800 */
+            "\"\xED\xA0\x80\"",
+            "\xED\xA0\x80",     /* bug: not corrected */
+            "\"\\uD800\"",      /* bug: want "\"\\uFFFF\"" */
+        },
+        {
+            /* \U+DB7F */
+            "\"\xED\xAD\xBF\"",
+            "\xED\xAD\xBF",     /* bug: not corrected */
+            "\"\\uDB7F\"",      /* bug: want "\"\\uFFFF\"" */
+        },
+        {
+            /* \U+DB80 */
+            "\"\xED\xAE\x80\"",
+            "\xED\xAE\x80",     /* bug: not corrected */
+            "\"\\uDB80\"",      /* bug: want "\"\\uFFFF\"" */
+        },
+        {
+            /* \U+DBFF */
+            "\"\xED\xAF\xBF\"",
+            "\xED\xAF\xBF",     /* bug: not corrected */
+            "\"\\uDBFF\"",      /* bug: want "\"\\uFFFF\"" */
+        },
+        {
+            /* \U+DC00 */
+            "\"\xED\xB0\x80\"",
+            "\xED\xB0\x80",     /* bug: not corrected */
+            "\"\\uDC00\"",      /* bug: want "\"\\uFFFF\"" */
+        },
+        {
+            /* \U+DF80 */
+            "\"\xED\xBE\x80\"",
+            "\xED\xBE\x80",     /* bug: not corrected */
+            "\"\\uDF80\"",      /* bug: want "\"\\uFFFF\"" */
+        },
+        {
+            /* \U+DFFF */
+            "\"\xED\xBF\xBF\"",
+            "\xED\xBF\xBF",     /* bug: not corrected */
+            "\"\\uDFFF\"",      /* bug: want "\"\\uFFFF\"" */
+        },
+        /* 5.2  Paired UTF-16 surrogates */
+        {
+            /* \U+D800\U+DC00 */
+            "\"\xED\xA0\x80\xED\xB0\x80\"",
+            "\xED\xA0\x80\xED\xB0\x80", /* bug: not corrected */
+            "\"\\uD800\\uDC00\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
+        },
+        {
+            /* \U+D800\U+DFFF */
+            "\"\xED\xA0\x80\xED\xBF\xBF\"",
+            "\xED\xA0\x80\xED\xBF\xBF", /* bug: not corrected */
+            "\"\\uD800\\uDFFF\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
+        },
+        {
+            /* \U+DB7F\U+DC00 */
+            "\"\xED\xAD\xBF\xED\xB0\x80\"",
+            "\xED\xAD\xBF\xED\xB0\x80", /* bug: not corrected */
+            "\"\\uDB7F\\uDC00\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
+        },
+        {
+            /* \U+DB7F\U+DFFF */
+            "\"\xED\xAD\xBF\xED\xBF\xBF\"",
+            "\xED\xAD\xBF\xED\xBF\xBF", /* bug: not corrected */
+            "\"\\uDB7F\\uDFFF\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
+        },
+        {
+            /* \U+DB80\U+DC00 */
+            "\"\xED\xAE\x80\xED\xB0\x80\"",
+            "\xED\xAE\x80\xED\xB0\x80", /* bug: not corrected */
+            "\"\\uDB80\\uDC00\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
+        },
+        {
+            /* \U+DB80\U+DFFF */
+            "\"\xED\xAE\x80\xED\xBF\xBF\"",
+            "\xED\xAE\x80\xED\xBF\xBF", /* bug: not corrected */
+            "\"\\uDB80\\uDFFF\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
+        },
+        {
+            /* \U+DBFF\U+DC00 */
+            "\"\xED\xAF\xBF\xED\xB0\x80\"",
+            "\xED\xAF\xBF\xED\xB0\x80", /* bug: not corrected */
+            "\"\\uDBFF\\uDC00\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
+        },
+        {
+            /* \U+DBFF\U+DFFF */
+            "\"\xED\xAF\xBF\xED\xBF\xBF\"",
+            "\xED\xAF\xBF\xED\xBF\xBF", /* bug: not corrected */
+            "\"\\uDBFF\\uDFFF\"", /* bug: want "\"\\uFFFF\\uFFFF\"" */
+        },
+        /* 5.3  Other illegal code positions */
+        {
+            /* \U+FFFE */
+            "\"\xEF\xBF\xBE\"",
+            "\xEF\xBF\xBE",     /* bug: not corrected */
+            "\"\\uFFFE\"",      /* bug: not corrected */
+        },
+        {
+            /* \U+FFFF */
+            "\"\xEF\xBF\xBF\"",
+            "\xEF\xBF\xBF",     /* bug: not corrected */
+            "\"\\uFFFF\"",      /* bug: not corrected */
+        },
+        {}
+    };
+    int i;
+    QObject *obj;
+    QString *str;
+    const char *json_in, *utf8_out, *utf8_in, *json_out;
+
+    for (i = 0; test_cases[i].json_in; i++) {
+        json_in = test_cases[i].json_in;
+        utf8_out = test_cases[i].utf8_out;
+        utf8_in = test_cases[i].utf8_in ?: test_cases[i].utf8_out;
+        json_out = test_cases[i].json_out ?: test_cases[i].json_in;
+
+        obj = qobject_from_json(json_in);
+        if (utf8_out) {
+            g_assert(obj);
+            g_assert(qobject_type(obj) == QTYPE_QSTRING);
+            str = qobject_to_qstring(obj);
+            g_assert_cmpstr(qstring_get_str(str), ==, utf8_out);
+        } else {
+            g_assert(!obj);
+        }
+        qobject_decref(obj);
+
+        obj = QOBJECT(qstring_from_str(utf8_in));
+        str = qobject_to_json(obj);
+        if (json_out) {
+            g_assert(str);
+            g_assert_cmpstr(qstring_get_str(str), ==, json_out);
+        } else {
+            g_assert(!str);
+        }
+        QDECREF(str);
+        qobject_decref(obj);
+
+        /*
+         * Disabled, because json_out currently contains the crap
+         * qobject_to_json() produces.
+         * FIXME Enable once these bugs have been fixed.
+         */
+        if (0 && json_out != json_in) {
+            obj = qobject_from_json(json_out);
+            g_assert(obj);
+            g_assert(qobject_type(obj) == QTYPE_QSTRING);
+            str = qobject_to_qstring(obj);
+            g_assert_cmpstr(qstring_get_str(str), ==, utf8_out);
+        }
+    }
+}
+
 static void vararg_string(void)
 {
     int i;
@@ -748,6 +1411,7 @@  int main(int argc, char **argv)
 
     g_test_add_func("/literals/string/simple", simple_string);
     g_test_add_func("/literals/string/escaped", escaped_string);
+    g_test_add_func("/literals/string/utf8", utf8_string);
     g_test_add_func("/literals/string/single_quote", single_quote_string);
     g_test_add_func("/literals/string/vararg", vararg_string);