vlibc/tests/test_string.c

/*
 * vlibc — string.h completion test (todo 8).
 *
 * Covers the new string search/memory functions end to end:
 *
 *   1. copy family: strcpy/strncpy (NUL padding), strcat/strncat (always
 *      NUL-terminated), L2 stpcpy/stpncpy (return the NUL position);
 *   2. search family: strchr/strrchr (including the NUL as a match),
 *      strspn/strcspn/strpbrk, strstr (empty/longer/overlapping needles);
 *   3. tokenizer: strtok/strtok_r — empty source yields NULL, consecutive
 *      delimiters produce NO empty tokens, an all-delimiter string yields
 *      NULL on the first call, and the delimiter string is never modified;
 *   4. collation: strcoll == strcmp and strxfrm (identity transform,
 *      returns strlen, truncates to n-1 bytes + NUL) — "C" locale only;
 *      L2 strcoll_l/strxfrm_l ignore the locale argument;
 *   5. memory: memchr (incl. negative c), memcmp ordering, L2 memccpy;
 *   6. misc: strnlen (stops at maxlen), strncmp (stops at NUL), strdup/
 *      strndup round-trips, strsignal (distinct non-null strings; unknown
 *      numbers format as "Unknown signal <N>"; signal 0 is asserted
 *      distinct + non-null only, per POSIX).
 *
 * The expected values were captured against the host glibc as the
 * ground-truth oracle for the corpus (see the task-8 evidence log); the
 * assertions below encode those golden results inline. Two strxfrm cases
 * intentionally assert VLIBc's pinned contract (n-1 bytes + NUL, return
 * strlen) rather than glibc's: POSIX leaves the dst contents UNSPECIFIED
 * when the return value is >= n.
 *
 * strdup/strndup allocate through the internal __libc_malloc seam
 * (src/internal/malloc.h); under make check the real allocator (todo 7)
 * provides it. For the STANDALONE verification of this todo the test links
 * a throwaway /tmp allocator stub (never committed) — see the evidence log.
 *
 * With `-p`, a representative sample of results is printed to stdout for
 * eyeball diffing; the assertions always run.
 *
 * No host libc headers are included (the -Iinclude path would shadow GCC's
 * internal headers); all output goes through raw SYS_write via
 * <vlibc/internal/test.h>. Not yet wired into make check (a later todo).
 *
 * Standalone build:
 *   gcc -Iinclude -DVLIBC_LEVEL=2 -std=c23 -Wall -Wextra -pedantic \
 *       -o /tmp/t8 tests/test_string.c \
 *       src/string/{strcpy,strncpy,strcat,strchr,strspn,strstr,strtok,strcoll,strdup,strnlen,strncmp,memchr,memcmp,strsignal,stpcpy,memccpy}.c \
 *       src/string/{strlen,strcmp}.c /tmp/allocstub.c \
 *       src/internal/errno.c src/internal/syscall_ret.c
 */

#include <string.h>

#include <vlibc/internal/test.h>

#include "../src/internal/malloc.h"

/* ---- shared helpers ---- */

/*
 * Collect up to cap tokens from a fresh copy of s using strtok; the copy is
 * consumed (delimiters become NUL), matching POSIX strtok semantics.
 */
static int
tok_collect(char *s, const char *sep, char *out[], int cap)
{
    char *t;
    int n = 0;

    t = strtok(s, sep);
    while (t != NULL && n < cap)
    {
        out[n++] = t;
        t = strtok(NULL, sep);
    }
    return n;
}

/* Same, but through strtok_r with an explicit state. */
static int
tokr_collect(char *s, const char *sep, char *out[], int cap)
{
    char *t;
    char *state = NULL;
    int n = 0;

    t = strtok_r(s, sep, &state);
    while (t != NULL && n < cap)
    {
        out[n++] = t;
        t = strtok_r(NULL, sep, &state);
    }
    return n;
}

/*
 * GCC's -Wstringop-truncation/-Wstringop-overread fire when the source
 * length is statically visible at a bounded-copy call site. The truncation
 * and oversized-n corpus cases below are exactly what those diagnostics
 * guard against — intentionally — so they go through noipa wrappers
 * (noipa, not just noinline: GCC's constprop clones ignore noinline at
 * -O2 and re-expose the call sites).
 */
static __attribute__((noipa)) char *
strncpy_opaque(char *dst, const char *src, size_t n)
{
    return strncpy(dst, src, n);
}

static __attribute__((noipa)) char *
strncat_opaque(char *dst, const char *src, size_t n)
{
    return strncat(dst, src, n);
}

static __attribute__((noipa)) char *
strndup_opaque(const char *s, size_t n)
{
    return strndup(s, n);
}

/* ---- test functions (one per checked behavior) ---- */

static int
test_strcpy(void)
{
    char buf[16];

    TEST_ASSERT_TRUE(strcpy(buf, "hello") == buf);
    TEST_ASSERT_STREQ(buf, "hello");
    TEST_ASSERT_TRUE(strcpy(buf, "") == buf);
    TEST_ASSERT_STREQ(buf, "");
    return 0;
}

static int
test_strncpy(void)
{
    char buf[8];

    /* Shorter src: NUL-padded to n. */
    memset(buf, 0x41, sizeof buf);
    TEST_ASSERT_TRUE(strncpy(buf, "hi", 5) == buf);
    TEST_ASSERT_STREQ(buf, "hi");
    TEST_ASSERT_EQ(buf[2], '\0');
    TEST_ASSERT_EQ(buf[3], '\0');
    TEST_ASSERT_EQ(buf[4], '\0');
    TEST_ASSERT_EQ(buf[5], 'A'); /* untouched past n */

    /* Src n bytes or longer: no NUL written within n. */
    memset(buf, 0x41, sizeof buf);
    TEST_ASSERT_TRUE(strncpy_opaque(buf, "hello", 3) == buf);
    TEST_ASSERT_EQ(buf[0], 'h');
    TEST_ASSERT_EQ(buf[1], 'e');
    TEST_ASSERT_EQ(buf[2], 'l');
    TEST_ASSERT_EQ(buf[3], 'A'); /* not NUL-terminated */

    /* n == 0: nothing written. */
    memset(buf, 0x41, sizeof buf);
    strncpy_opaque(buf, "hello", 0);
    TEST_ASSERT_EQ(buf[0], 'A');
    return 0;
}

static int
test_strcat(void)
{
    char buf[16];

    strcpy(buf, "hello");
    TEST_ASSERT_TRUE(strcat(buf, " world") == buf);
    TEST_ASSERT_STREQ(buf, "hello world");
    strcpy(buf, "");
    strcat(buf, "x");
    TEST_ASSERT_STREQ(buf, "x");
    return 0;
}

static int
test_strncat(void)
{
    char buf[16];

    strcpy(buf, "abc");
    TEST_ASSERT_TRUE(strncat_opaque(buf, "defgh", 3) == buf);
    TEST_ASSERT_STREQ(buf, "abcdef");

    strcpy(buf, "abc");
    strncat(buf, "defgh", 10);
    TEST_ASSERT_STREQ(buf, "abcdefgh");

    strcpy(buf, "abc");
    strncat_opaque(buf, "xyz", 0);
    TEST_ASSERT_STREQ(buf, "abc");
    return 0;
}

static int
test_strchr(void)
{
    const char *s = "hello";

    TEST_ASSERT_EQ(strchr(s, 'l') - s, 2);
    TEST_ASSERT_EQ(strchr(s, 'h') - s, 0);
    TEST_ASSERT_NULL(strchr(s, 'z'));
    TEST_ASSERT_EQ(strchr(s, '\0') - s, 5);
    return 0;
}

static int
test_strrchr(void)
{
    const char *s = "hello";

    TEST_ASSERT_EQ(strrchr(s, 'l') - s, 3);
    TEST_ASSERT_EQ(strrchr(s, 'h') - s, 0);
    TEST_ASSERT_NULL(strrchr(s, 'z'));
    TEST_ASSERT_EQ(strrchr(s, '\0') - s, 5);
    return 0;
}

static int
test_strspn(void)
{
    TEST_ASSERT_EQ(strspn("abcba", "abc"), 5);
    TEST_ASSERT_EQ(strspn("abcba", "ab"), 2);
    TEST_ASSERT_EQ(strspn("abcba", "z"), 0);
    TEST_ASSERT_EQ(strspn("", "ab"), 0);
    return 0;
}

static int
test_strcspn(void)
{
    TEST_ASSERT_EQ(strcspn("abcba", "b"), 1);
    TEST_ASSERT_EQ(strcspn("abcba", "z"), 5);
    TEST_ASSERT_EQ(strcspn("abcba", "a"), 0);
    TEST_ASSERT_EQ(strcspn("", "ab"), 0);
    return 0;
}

static int
test_strpbrk(void)
{
    const char *s = "hello";

    TEST_ASSERT_EQ(strpbrk(s, "aeiou") - s, 1);
    TEST_ASSERT_EQ(strpbrk(s, "h") - s, 0);
    TEST_ASSERT_NULL(strpbrk(s, "xyz"));
    TEST_ASSERT_NULL(strpbrk("", "x"));
    return 0;
}

static int
test_strstr(void)
{
    const char *h = "hello world";

    TEST_ASSERT_EQ(strstr(h, "world") - h, 6);
    TEST_ASSERT_EQ(strstr(h, "hello") - h, 0);
    TEST_ASSERT_EQ(strstr(h, "o") - h, 4);
    TEST_ASSERT_NULL(strstr(h, "helloo"));
    TEST_ASSERT_NULL(strstr("hi", "hello"));           /* needle longer than haystack */
    TEST_ASSERT_TRUE(strstr(h, "") == h);              /* empty needle matches haystack */
    TEST_ASSERT_EQ(strstr("aaaa", "aaa") - "aaaa", 0); /* overlapping */
    TEST_ASSERT_EQ(strstr("banana", "nan") - "banana", 2);
    TEST_ASSERT_EQ(strstr("abc", "bc") - "abc", 1);
    return 0;
}

static int
test_strtok(void)
{
    char buf[32];
    char *out[8];
    int n;

    /* Empty source: first call yields NULL (no tokens). */
    strcpy(buf, "");
    TEST_ASSERT_NULL(strtok(buf, " "));

    /* Consecutive delimiters produce NO empty tokens. */
    strcpy(buf, "a,,b");
    n = tok_collect(buf, ",", out, 8);
    TEST_ASSERT_EQ(n, 2);
    TEST_ASSERT_STREQ(out[0], "a");
    TEST_ASSERT_STREQ(out[1], "b");

    /* All delimiters: first call yields NULL. */
    strcpy(buf, ",,,");
    TEST_ASSERT_NULL(strtok(buf, ","));

    /* Leading + trailing delimiters are skipped. */
    strcpy(buf, "xxhelloxx");
    n = tok_collect(buf, "x", out, 8);
    TEST_ASSERT_EQ(n, 1);
    TEST_ASSERT_STREQ(out[0], "hello");

    /* No delimiter present: the whole string is one token. */
    strcpy(buf, "hello");
    n = tok_collect(buf, " ", out, 8);
    TEST_ASSERT_EQ(n, 1);
    TEST_ASSERT_STREQ(out[0], "hello");

    /* Multiple whitespace runs collapse to the same tokens. */
    strcpy(buf, "a b  c");
    n = tok_collect(buf, " ", out, 8);
    TEST_ASSERT_EQ(n, 3);
    TEST_ASSERT_STREQ(out[0], "a");
    TEST_ASSERT_STREQ(out[1], "b");
    TEST_ASSERT_STREQ(out[2], "c");

    /* The delimiter string is never modified. */
    {
        static char sep[] = ",;";
        char *sep_before = sep;

        strcpy(buf, "a,b;c");
        (void)tok_collect(buf, sep, out, 8);
        TEST_ASSERT_TRUE(sep == sep_before);
        TEST_ASSERT_EQ(sep[0], ',');
        TEST_ASSERT_EQ(sep[1], ';');
    }
    return 0;
}

static int
test_strtok_r(void)
{
    char buf[32];
    char *out[8];
    int n;

    strcpy(buf, "a,,b");
    n = tokr_collect(buf, ",", out, 8);
    TEST_ASSERT_EQ(n, 2);
    TEST_ASSERT_STREQ(out[0], "a");
    TEST_ASSERT_STREQ(out[1], "b");

    strcpy(buf, "");
    TEST_ASSERT_NULL(strtok_r(buf, " ", &(char *){NULL}));

    /* Two interleaved scans keep independent state. */
    {
        char s1[16];
        char s2[16];
        char *state1 = NULL;
        char *state2 = NULL;
        char *t1;
        char *t2;

        strcpy(s1, "one two");
        strcpy(s2, "red green blue");

        t1 = strtok_r(s1, " ", &state1);
        t2 = strtok_r(s2, " ", &state2);
        TEST_ASSERT_STREQ(t1, "one");
        TEST_ASSERT_STREQ(t2, "red");
        t1 = strtok_r(NULL, " ", &state1);
        TEST_ASSERT_STREQ(t1, "two");
        t2 = strtok_r(NULL, " ", &state2);
        TEST_ASSERT_STREQ(t2, "green");
        t1 = strtok_r(NULL, " ", &state1);
        TEST_ASSERT_NULL(t1);
        t2 = strtok_r(NULL, " ", &state2);
        TEST_ASSERT_STREQ(t2, "blue");
    }
    return 0;
}

static int
test_strcoll(void)
{
    TEST_ASSERT_EQ(strcoll("apple", "banana"), strcmp("apple", "banana"));
    TEST_ASSERT_EQ(strcoll("apple", "banana") < 0, 1);
    TEST_ASSERT_EQ(strcoll("b", "a") > 0, 1);
    TEST_ASSERT_EQ(strcoll("same", "same"), 0);
    TEST_ASSERT_EQ(strcoll("A", "a"), strcmp("A", "a"));
    TEST_ASSERT_EQ(strcoll("", ""), 0);
    return 0;
}

static int
test_strxfrm(void)
{
    char xf[16];

    /* Identity transform, returns strlen(src). */
    TEST_ASSERT_EQ(strxfrm(xf, "hello", sizeof xf), 5);
    TEST_ASSERT_STREQ(xf, "hello");

    /* Truncation: at most n-1 bytes + NUL, return still 5. */
    TEST_ASSERT_EQ(strxfrm(xf, "hello", 4), 5);
    TEST_ASSERT_STREQ(xf, "hel");

    /* n == 0: nothing written, return still 5. */
    memset(xf, 0x41, sizeof xf);
    TEST_ASSERT_EQ(strxfrm(xf, "hello", 0), 5);
    TEST_ASSERT_EQ(xf[0], 'A');

    /* n == 1: only the NUL. */
    TEST_ASSERT_EQ(strxfrm(xf, "hello", 1), 5);
    TEST_ASSERT_EQ(xf[0], '\0');

    TEST_ASSERT_EQ(strxfrm(xf, "", sizeof xf), 0);
    TEST_ASSERT_STREQ(xf, "");
    return 0;
}

static int
test_strdup(void)
{
    char src[] = "hello";
    char *p = strdup(src);

    TEST_ASSERT_TRUE(p != NULL);
    TEST_ASSERT_STREQ(p, "hello");
    TEST_ASSERT_TRUE(p != src); /* a real copy, not the source array */
    __libc_free(p);

    p = strdup("");
    TEST_ASSERT_TRUE(p != NULL);
    TEST_ASSERT_STREQ(p, "");
    __libc_free(p);
    return 0;
}

static int
test_strndup(void)
{
    char *p = strndup("abcdef", 3);

    TEST_ASSERT_TRUE(p != NULL);
    TEST_ASSERT_STREQ(p, "abc");
    __libc_free(p);

    p = strndup_opaque("ab", 10); /* n beyond the NUL: whole string */
    TEST_ASSERT_TRUE(p != NULL);
    TEST_ASSERT_STREQ(p, "ab");
    __libc_free(p);

    p = strndup("xyz", 0); /* n == 0: empty string */
    TEST_ASSERT_TRUE(p != NULL);
    TEST_ASSERT_STREQ(p, "");
    __libc_free(p);

    p = strndup("", 0);
    TEST_ASSERT_TRUE(p != NULL);
    TEST_ASSERT_STREQ(p, "");
    __libc_free(p);
    return 0;
}

static int
test_strnlen(void)
{
    TEST_ASSERT_EQ(strnlen("abc", 2), 2);
    TEST_ASSERT_EQ(strnlen("abc", 10), 3);
    TEST_ASSERT_EQ(strnlen("abc", 0), 0);
    TEST_ASSERT_EQ(strnlen("", 5), 0);
    return 0;
}

static int
test_strncmp(void)
{
    TEST_ASSERT_EQ(strncmp("abc", "abc", 3), 0);
    TEST_ASSERT_EQ(strncmp("ab", "abc", 2), 0);
    TEST_ASSERT_EQ(strncmp("ab", "ac", 1), 0);
    TEST_ASSERT_EQ(strncmp("abc", "abd", 3) < 0, 1);
    TEST_ASSERT_EQ(strncmp("abd", "abc", 3) > 0, 1);
    TEST_ASSERT_EQ(strncmp("x", "y", 0), 0); /* n == 0 */
    /* Stops at the first NUL even when n is larger. */
    TEST_ASSERT_EQ(strncmp("a\0b", "a\0c", 5), 0);
    TEST_ASSERT_EQ(strncmp("a\0b", "a", 5), 0);
    return 0;
}

static int
test_memchr(void)
{
    const char *s = "hello";
    unsigned char high[] = {0x41, 0xff, 0x00};

    TEST_ASSERT_EQ((char *)memchr(s, 'l', 5) - s, 2);
    TEST_ASSERT_NULL(memchr(s, 'z', 5));
    TEST_ASSERT_NULL(memchr(s, 'h', 0)); /* n == 0 */
    TEST_ASSERT_EQ((char *)memchr(s, '\0', 6) - s, 5);
    /* Negative c searches for the matching high byte. */
    TEST_ASSERT_EQ((char *)memchr(high, 0xff, 3) - (char *)high, 1);
    return 0;
}

static int
test_memcmp(void)
{
    unsigned char hi[] = {0xff, 0x00};
    unsigned char lo[] = {0x7f, 0x00};

    TEST_ASSERT_EQ(memcmp("abc", "abc", 3), 0);
    TEST_ASSERT_EQ(memcmp("abc", "abd", 3) < 0, 1);
    TEST_ASSERT_EQ(memcmp("abd", "abc", 3) > 0, 1);
    TEST_ASSERT_EQ(memcmp("x", "y", 0), 0); /* n == 0 */
    /* Bytes compare as unsigned char: 0xff > 0x7f. */
    TEST_ASSERT_EQ(memcmp(hi, lo, 1) > 0, 1);
    TEST_ASSERT_EQ(memcmp(lo, hi, 1) < 0, 1);
    /* Does not stop at NUL bytes. */
    TEST_ASSERT_EQ(memcmp("a\0b", "a\0c", 3) < 0, 1);
    return 0;
}

static int
test_strsignal(void)
{
    /* Known signals: pinned texts (vlibc's own table, x86_64 numbers). */
    TEST_ASSERT_STREQ(strsignal(2), "Interrupt");
    TEST_ASSERT_STREQ(strsignal(11), "Segmentation fault");
    TEST_ASSERT_STREQ(strsignal(1), "Hangup");
    TEST_ASSERT_STREQ(strsignal(9), "Killed");
    TEST_ASSERT_STREQ(strsignal(31), "Bad system call");

    /* Distinct strings for distinct known signals. */
    TEST_ASSERT_TRUE(strsignal(2) != strsignal(11));
    TEST_ASSERT_TRUE(strsignal(1) != strsignal(2));

    /* Signal 0: non-null and distinct, text deliberately not pinned. */
    TEST_ASSERT_TRUE(strsignal(0) != NULL);
    TEST_ASSERT_TRUE(strsignal(0) != strsignal(1));
    TEST_ASSERT_TRUE(strsignal(0) != strsignal(2));

    /* Unknown numbers: formatted, non-null, distinct. */
    TEST_ASSERT_STREQ(strsignal(999), "Unknown signal 999");
    TEST_ASSERT_STREQ(strsignal(32), "Unknown signal 32");
    TEST_ASSERT_TRUE(strsignal(-1) != NULL);
    TEST_ASSERT_STREQ(strsignal(-1), "Unknown signal -1");
    return 0;
}

static int
test_stpcpy_stpncpy(void)
{
    char buf[8];
    char *end;

    end = stpcpy(buf, "abc");
    TEST_ASSERT_EQ(end - buf, 3);
    TEST_ASSERT_STREQ(buf, "abc");
    TEST_ASSERT_EQ(*end, '\0');

    end = stpcpy(buf, "");
    TEST_ASSERT_EQ(end - buf, 0);
    TEST_ASSERT_EQ(buf[0], '\0');

    /* Short src: NUL-padded; return points at the first NUL. */
    end = stpncpy(buf, "abc", 8);
    TEST_ASSERT_EQ(end - buf, 3);
    TEST_ASSERT_STREQ(buf, "abc");

    /* Src >= n: no NUL written; return is dst + n. */
    memset(buf, 'X', sizeof buf);
    end = stpncpy(buf, "abcdefgh", 4);
    TEST_ASSERT_EQ(end - buf, 4);
    TEST_ASSERT_EQ(buf[0], 'a');
    TEST_ASSERT_EQ(buf[3], 'd');
    TEST_ASSERT_EQ(buf[4], 'X');

    /* n == 0: return dst, nothing written. */
    memset(buf, 'X', sizeof buf);
    end = stpncpy(buf, "abc", 0);
    TEST_ASSERT_EQ(end - buf, 0);
    TEST_ASSERT_EQ(buf[0], 'X');
    return 0;
}

static int
test_memccpy(void)
{
    unsigned char buf[16];
    void *p;

    p = memccpy(buf, "hello world", ' ', 20);
    TEST_ASSERT_EQ((char *)p - (char *)buf, 6); /* one past the ' ' */
    TEST_ASSERT_EQ(buf[5], ' ');

    /* c never appears within n: NULL, full copy made. */
    p = memccpy(buf, "hello", 'z', 20);
    TEST_ASSERT_NULL(p);
    TEST_ASSERT_EQ(buf[4], 'o');

    /* c exists but beyond n: NULL. */
    p = memccpy(buf, "hello", 'o', 3);
    TEST_ASSERT_NULL(p);

    /* n == 0: NULL, nothing written. */
    memset(buf, 'X', sizeof buf);
    p = memccpy(buf, "hello", 'h', 0);
    TEST_ASSERT_NULL(p);
    TEST_ASSERT_EQ(buf[0], 'X');
    return 0;
}

static int
test_strcoll_l(void)
{
    char xf[16];

    /* The locale argument is ignored ("C" locale behavior). */
    TEST_ASSERT_EQ(strcoll_l("a", "b", NULL), strcoll("a", "b"));
    TEST_ASSERT_EQ(strcoll_l("a", "b", NULL) < 0, 1);
    TEST_ASSERT_EQ(strcoll_l("x", "x", NULL), 0);
    TEST_ASSERT_EQ(strxfrm_l(xf, "hi", sizeof xf, NULL), strxfrm(xf, "hi", sizeof xf));
    TEST_ASSERT_STREQ(xf, "hi");
    return 0;
}

/* ---- register + runner ---- */

static const struct vlibc_test tests[] = {
    {"strcpy", test_strcpy},       {"strncpy", test_strncpy},
    {"strcat", test_strcat},       {"strncat", test_strncat},
    {"strchr", test_strchr},       {"strrchr", test_strrchr},
    {"strspn", test_strspn},       {"strcspn", test_strcspn},
    {"strpbrk", test_strpbrk},     {"strstr", test_strstr},
    {"strtok", test_strtok},       {"strtok_r", test_strtok_r},
    {"strcoll", test_strcoll},     {"strxfrm", test_strxfrm},
    {"strdup", test_strdup},       {"strndup", test_strndup},
    {"strnlen", test_strnlen},     {"strncmp", test_strncmp},
    {"memchr", test_memchr},       {"memcmp", test_memcmp},
    {"strsignal", test_strsignal}, {"stpcpy/stpncpy", test_stpcpy_stpncpy},
    {"memccpy", test_memccpy},     {"strcoll_l/strxfrm_l", test_strcoll_l},
};

/* -p mode: print a representative sample for eyeball diffing. */
static void
print_sample(void)
{
    char buf[32];
    char *out[8];
    int n;
    char *t;

    vlibc_test_say(1, "strtok(a,,b, ,)= ");
    strcpy(buf, "a,,b");
    n = tok_collect(buf, ",", out, 8);
    for (int i = 0; i < n; i++)
    {
        vlibc_test_say(1, "[");
        vlibc_test_say(1, out[i]);
        vlibc_test_say(1, "]");
    }
    vlibc_test_say(1, "\nstrxfrm(hello,n=4)=len ");
    vlibc_test_say_dec(1, (unsigned long)strxfrm(buf, "hello", 4));
    vlibc_test_say(1, " dst=\"");
    vlibc_test_say(1, buf);
    vlibc_test_say(1, "\"\nstrsignal(2)=\"");
    vlibc_test_say(1, strsignal(2));
    vlibc_test_say(1, "\" strsignal(0)=\"");
    vlibc_test_say(1, strsignal(0));
    vlibc_test_say(1, "\" strsignal(999)=\"");
    vlibc_test_say(1, strsignal(999));
    vlibc_test_say(1, "\"\n");
    t = strdup("dup-ok");
    vlibc_test_say(1, "strdup(dup-ok)=\"");
    vlibc_test_say(1, t);
    vlibc_test_say(1, "\"\n");
    __libc_free(t);
}

/*
 * Own main (not TEST_MAIN): supports the -p print mode. Everything else
 * follows the TEST_MAIN contract — same output shape, 0 on all-pass.
 */
int
main(int argc, char **argv)
{
    const size_t count = sizeof tests / sizeof tests[0];
    size_t passed = 0;
    size_t i;

    if (argc > 1 && strcmp(argv[1], "-p") == 0)
    {
        print_sample();
    }

    for (i = 0; i < count; i++)
    {
        int before = vlibc_test_failures;

        vlibc_test_say(1, "RUN ");
        vlibc_test_say(1, tests[i].name);
        vlibc_test_say(1, ": ");
        if (tests[i].run() == 0 && vlibc_test_failures == before)
        {
            vlibc_test_say(1, "PASS\n");
            passed++;
        }
        else
        {
            vlibc_test_say(1, "FAIL\n");
        }
    }

    vlibc_test_say(1, "SUMMARY: ");
    vlibc_test_say_dec(1, (unsigned long)passed);
    vlibc_test_say(1, "/");
    vlibc_test_say_dec(1, (unsigned long)count);
    vlibc_test_say(1, " passed, ");
    vlibc_test_say_dec(1, (unsigned long)vlibc_test_failures);
    vlibc_test_say(1, " assertion failure(s)\n");

    return passed == count ? 0 : 1;
}