/*
 * unittests.c - unit tests for dynamic byte strings
 * Copyright 2010  Lars Wirzenius
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#define _GNU_SOURCE

#include <setjmp.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include "dynstr.h"


#define FAIL(msg) \
    do { \
        printf("FAIL: %s\n", msg); \
        return false; \
    } while (0)


#define FAIL_UNLESS(cond) \
    do { \
        if (!(cond)) { \
            printf("FAIL: %s:%d: %s\n", \
                __FUNCTION__, __LINE__, #cond); \
            return false;\
        } \
    } while (0)


#define FAIL_UNLESS_EQUAL(a,b) \
    do { \
        if ((a) != (b)) { \
            printf("FAIL: %s:%d: not equal: '%s' and '%s'\n", \
                __FUNCTION__, __LINE__, #a, #b); \
            return false;\
        } \
    } while (0)



#define MAX_STRINGS 128
static Dynstr *strings[MAX_STRINGS];
static int num_strings;

static void add(Dynstr *dynstr)
{
    if (num_strings < MAX_STRINGS) {
        strings[num_strings] = dynstr;
        num_strings++;
    }
}

static Dynstr *new_from_cstring(const char *cstring)
{
    Dynstr *dynstr;
    
    dynstr = dynstr_new_from_cstring(cstring);
    add(dynstr);
    return dynstr;
}

static Dynstr *substr(Dynstr *dynstr, size_t offset, size_t size)
{
    Dynstr *sub;
    
    sub = dynstr_substr(dynstr, offset, size);
    add(sub);
    return sub;
}

static void free_all_strings(void)
{
    while (num_strings > 0) {
        num_strings--;
        dynstr_free(strings[num_strings]);
    }
}


static int test_default_error_handler_is_indicate(void)
{
    FAIL_UNLESS_EQUAL(dynstr_get_malloc_error_handler(),
                      dynstr_malloc_error_indicate);
    return true;
}


static int test_sets_error_handler(void)
{
    dynstr_set_malloc_error_handler(dynstr_malloc_error_abort);
    FAIL_UNLESS_EQUAL(dynstr_get_malloc_error_handler(),
                      dynstr_malloc_error_abort);
    return true;
}


static int test_init_resets_error_handler(void)
{
    dynstr_set_malloc_error_handler(dynstr_malloc_error_abort);
    dynstr_init();
    FAIL_UNLESS_EQUAL(dynstr_get_malloc_error_handler(),
                      dynstr_malloc_error_indicate);
    return true;
}


static int test_indicate_handler_returns(void)
{
    dynstr_malloc_error_indicate(0, 0, NULL);
    return true;
}


static jmp_buf env;
static void abort_handler(int signo)
{
    longjmp(env, 1);
}


static int test_abort_handler_calls_abort(void)
{
    struct sigaction act;
    struct sigaction oldact;
    
    if (setjmp(env) == 0) {
        act.sa_handler = abort_handler;
        sigemptyset(&act.sa_mask);
        act.sa_flags = 0;
        sigaction(SIGABRT, &act, &oldact);
        dynstr_set_malloc_error_handler(dynstr_malloc_error_abort);
        dynstr_malloc_error_abort(0, 0, 0);
        FAIL("dynstr_malloc_error_abort returned");
    } else {
        sigaction(SIGABRT, &oldact, NULL);
    }
    return true;
}


static bool error_handler_called;

static void error_handler(int error, size_t size, void *oldptr)
{
    error_handler_called = true;
}

static int fail_malloc_after;

static void *fail_malloc(size_t size)
{
    if (fail_malloc_after <= 0)
        return NULL;
    --fail_malloc_after;
    return malloc(size);
}

static int test_alloc_calls_error_handler(void)
{
    Dynstr *dynstr;
    
    error_handler_called = false;
    dynstr_set_malloc_error_handler(error_handler);
    dynstr_set_malloc(fail_malloc);
    dynstr = dynstr_new_empty();
    FAIL_UNLESS_EQUAL(dynstr, NULL);
    FAIL_UNLESS_EQUAL(error_handler_called, true);
    return true;
}

static int test_alloc_does_not_call_error_handler(void)
{
    Dynstr *dynstr;
    
    error_handler_called = false;
    dynstr_set_malloc_error_handler(error_handler);
    dynstr_set_malloc(malloc);
    dynstr = dynstr_new_empty();
    FAIL_UNLESS_EQUAL(error_handler_called, false);
    dynstr_free(dynstr);
    return true;
}


static int test_uses_malloc_by_default(void)
{
    dynstr_init();
    FAIL_UNLESS_EQUAL(dynstr_get_malloc(), malloc);
    return true;
}


static int test_sets_malloc(void)
{
    dynstr_set_malloc(fail_malloc);
    FAIL_UNLESS_EQUAL(dynstr_get_malloc(), fail_malloc);
    return true;
}


static int test_init_resets_malloc(void)
{
    dynstr_set_malloc(fail_malloc);
    dynstr_init();
    FAIL_UNLESS_EQUAL(dynstr_get_malloc(), malloc);
    return true;
}


static int test_empty_string_is_empty(void)
{
    Dynstr *dynstr;
    
    dynstr = dynstr_new_empty();
    FAIL_UNLESS_EQUAL(dynstr_len(dynstr), 0);
    FAIL_UNLESS_EQUAL(dynstr_is_empty(dynstr), true);
    dynstr_free(dynstr);
    return true;
}


static int test_new_returns_NULL_upon_first_allocation_failure(void)
{
    Dynstr *dynstr;

    dynstr_init();
    dynstr_set_malloc(fail_malloc);    
    dynstr = dynstr_new_empty();
    FAIL_UNLESS_EQUAL(dynstr, NULL);
    return true;
}


static int test_creates_from_cstring(void)
{
    const char bytes[] = "asdfasdfafdasdfasdfqw4tb";
    char newbytes[sizeof(bytes)];
    Dynstr *dynstr;
    size_t size;
    
    dynstr = new_from_cstring(bytes);
    FAIL_UNLESS_EQUAL(dynstr_len(dynstr), strlen(bytes));

    size = dynstr_memcpy(newbytes, dynstr, 0, strlen(bytes));
    FAIL_UNLESS_EQUAL(size, strlen(bytes));
    FAIL_UNLESS_EQUAL(memcmp(bytes, newbytes, strlen(bytes)), 0);
    
    return true;
}


static int test_creates_from_memory(void)
{
    const char bytes[] = "asdfasdfafdasdfasdfqw4tb";
    char newbytes[sizeof(bytes)];
    Dynstr *dynstr;
    size_t size;
    
    dynstr = dynstr_new_from_memory(bytes, sizeof(bytes));
    FAIL_UNLESS_EQUAL(dynstr_len(dynstr), sizeof(bytes));

    size = dynstr_memcpy(newbytes, dynstr, 0, sizeof(bytes));
    FAIL_UNLESS_EQUAL(size, sizeof(bytes));
    FAIL_UNLESS_EQUAL(memcmp(bytes, newbytes, sizeof(bytes)), 0);

    dynstr_free(dynstr);
    return true;
}


static int test_creates_from_constant_cstring(void)
{
    char bytes[] = "asdfasdfafdasdfasdfqw4tb";
    char newbytes[sizeof(bytes)];
    Dynstr *dynstr;
    size_t size;
    
    dynstr = dynstr_new_from_constant_cstring(bytes);
    FAIL_UNLESS_EQUAL(dynstr_len(dynstr), strlen(bytes));

    size = dynstr_memcpy(newbytes, dynstr, 0, strlen(bytes));
    FAIL_UNLESS_EQUAL(size, strlen(bytes));
    FAIL_UNLESS_EQUAL(memcmp(bytes, newbytes, strlen(bytes)), 0);
    
    /* Creating a dynstr from a supposedly constant C string should
       make the dynstr re-use the C string's memory area. Thus,
       if we modify the C string (even though we should not), the
       dynstr should also change. */
    bytes[0] = 'x';
    dynstr_memcpy(newbytes, dynstr, 0, strlen(bytes));
    FAIL_UNLESS_EQUAL(memcmp(bytes, newbytes, strlen(bytes)), 0);
    
    dynstr_free(dynstr);
    return true;
}


static int test_creates_from_constant_memory(void)
{
    char bytes[] = "asdfasdfafdasdfasdfqw4tb";
    char newbytes[sizeof(bytes)];
    Dynstr *dynstr;
    size_t size;
    
    dynstr = dynstr_new_from_constant_memory(bytes, sizeof(bytes));
    FAIL_UNLESS_EQUAL(dynstr_len(dynstr), sizeof(bytes));

    size = dynstr_memcpy(newbytes, dynstr, 0, sizeof(bytes));
    FAIL_UNLESS_EQUAL(size, sizeof(bytes));
    FAIL_UNLESS_EQUAL(memcmp(bytes, newbytes, sizeof(bytes)), 0);

    bytes[0] = 'x';
    dynstr_memcpy(newbytes, dynstr, 0, sizeof(bytes));
    FAIL_UNLESS_EQUAL(memcmp(bytes, newbytes, sizeof(bytes)), 0);

    dynstr_free(dynstr);
    return true;
}


static int test_memcpy_returns_zero_if_offset_is_too_large(void)
{
    Dynstr *dynstr;
    char mem[1024];
    
    dynstr = new_from_cstring("hello");
    FAIL_UNLESS_EQUAL(dynstr_memcpy(mem, dynstr, dynstr_len(dynstr), 1), 0);
    FAIL_UNLESS_EQUAL(dynstr_memcpy(mem, dynstr, dynstr_len(dynstr) + 1, 1), 0);
    return true;
}


static int test_memcpy_truncates_if_copying_too_much(void)
{
    Dynstr *dynstr;
    char mem[1024];
    size_t len;
    
    dynstr = new_from_cstring("hello");
    len = dynstr_len(dynstr);
    FAIL_UNLESS_EQUAL(dynstr_memcpy(mem, dynstr, 0, len), len);
    FAIL_UNLESS_EQUAL(dynstr_memcpy(mem, dynstr, 0, len + 1), len);
    return true;
}


static int test_memcpy_copies_whole_string_ok(void)
{
    Dynstr *dynstr;
    const char data[] = "hello";
    char mem[1024];
    size_t len;
    
    dynstr = new_from_cstring(data);
    len = dynstr_len(dynstr);
    dynstr_memcpy(mem, dynstr, 0, len);
    FAIL_UNLESS_EQUAL(memcmp(data, mem, len), 0);
    return true;
}


static int test_memcpy_copies_substring_ok(void)
{
    Dynstr *dynstr;
    const char data[] = "hello";
    char mem[1024];
    size_t len;
    
    dynstr = new_from_cstring(data);
    len = dynstr_len(dynstr);
    dynstr_memcpy(mem, dynstr, 1, len-2);
    FAIL_UNLESS_EQUAL(memcmp(data + 1, mem, len-2), 0);
    return true;
}


static int test_copies_empty_substring_ok(void)
{
    Dynstr *dynstr;
    Dynstr *sub;
    size_t size;
    char buf[1024];
    
    dynstr = new_from_cstring("abcdef");
    sub = substr(dynstr, 1, 0);
    size = dynstr_memcpy(buf, sub, 0, dynstr_len(sub));
    FAIL_UNLESS_EQUAL(size, 0);
    return true;
}


static int test_copies_single_byte_substring_ok(void)
{
    Dynstr *dynstr;
    Dynstr *sub;
    size_t size;
    char buf[1024];
    
    dynstr = new_from_cstring("abcdef");
    sub = substr(dynstr, 1, 1);
    size = dynstr_memcpy(buf, sub, 0, dynstr_len(sub));
    FAIL_UNLESS_EQUAL(size, 1);
    FAIL_UNLESS_EQUAL(memcmp(buf, "b", 1), 0);
    return true;
}


static int test_copies_middle_substring_ok(void)
{
    Dynstr *dynstr;
    Dynstr *sub;
    size_t size;
    char buf[1024];
    
    dynstr = new_from_cstring("abcdef");
    sub = substr(dynstr, 1, 4);
    size = dynstr_memcpy(buf, sub, 0, dynstr_len(sub));
    FAIL_UNLESS_EQUAL(size, 4);
    FAIL_UNLESS_EQUAL(memcmp(buf, "bcde", 4), 0);
    return true;
}


static int test_copies_initial_substring_ok(void)
{
    Dynstr *dynstr;
    Dynstr *sub;
    size_t size;
    char buf[1024];
    
    dynstr = new_from_cstring("abcdef");
    sub = substr(dynstr, 0, 5);
    size = dynstr_memcpy(buf, sub, 0, dynstr_len(sub));
    FAIL_UNLESS_EQUAL(size, 5);
    FAIL_UNLESS_EQUAL(memcmp(buf, "abcde", 5), 0);
    return true;
}


static int test_copies_final_substring_ok(void)
{
    Dynstr *dynstr;
    Dynstr *sub;
    size_t size;
    char buf[1024];
    
    dynstr = new_from_cstring("abcdef");
    sub = substr(dynstr, 1, 5);
    size = dynstr_memcpy(buf, sub, 0, dynstr_len(sub));
    FAIL_UNLESS_EQUAL(size, 5);
    FAIL_UNLESS_EQUAL(memcmp(buf, "bcdef", 5), 0);
    return true;
}


static int test_copies_empty_substring_when_offset_too_big(void)
{
    Dynstr *dynstr;
    Dynstr *sub;
    size_t size;
    char buf[1024];
    
    dynstr = new_from_cstring("abcdef");
    sub = substr(dynstr, 100, 1);
    size = dynstr_memcpy(buf, sub, 0, dynstr_len(sub));
    FAIL_UNLESS_EQUAL(size, 0);
    return true;
}


static int test_copies_partial_substring_when_length_too_big(void)
{
    Dynstr *dynstr;
    Dynstr *sub;
    size_t size;
    char buf[1024];
    
    dynstr = new_from_cstring("abcdef");
    sub = substr(dynstr, 1, 6);
    size = dynstr_memcpy(buf, sub, 0, dynstr_len(sub));
    FAIL_UNLESS_EQUAL(size, 5);
    FAIL_UNLESS_EQUAL(memcmp(buf, "bcdef", 5), 0);
    return true;
}


static int test_strdup_duplicates_string(void)
{
    Dynstr *dynstr;
    char *cstring;
    char data[] = "hello, world";
    
    dynstr = dynstr_new_from_constant_cstring(data);
    cstring = dynstr_strdup(dynstr);
    FAIL_UNLESS_EQUAL(memcmp(data, cstring, sizeof(data)), 0);
    free(cstring);
    dynstr_free(dynstr);
    return true;
}


static int test_cats_ok(void)
{
    Dynstr *a;
    Dynstr *b;
    Dynstr *c;
    char buf[1024];
    size_t size;
    
    a = new_from_cstring("abc");
    b = new_from_cstring("def");
    c = dynstr_cat(a, b);
    FAIL_UNLESS_EQUAL(dynstr_len(c), 6);
    size = dynstr_memcpy(buf, c, 0, dynstr_len(c));
    FAIL_UNLESS_EQUAL(size, 6);
    FAIL_UNLESS_EQUAL(memcmp(buf, "abcdef", 6), 0);
    dynstr_free(c);
    return true;
}


static int test_cat_returns_NULL_for_first_malloc_failure(void)
{
    Dynstr *a;
    Dynstr *b;
    Dynstr *c;

    a = new_from_cstring("abc");
    b = new_from_cstring("def");
    dynstr_set_malloc(fail_malloc);
    c = dynstr_cat(a, b);
    FAIL_UNLESS_EQUAL(c, NULL);
    return true;
}


static int test_byteat_reports_correct_character(void)
{
    Dynstr *dynstr;
    
    dynstr = new_from_cstring("abc");
    FAIL_UNLESS_EQUAL(dynstr_byte_at(dynstr, 1), 'b');
    return true;
}


static int test_byteat_reports_error_for_too_large_offset(void)
{
    Dynstr *dynstr;
    
    dynstr = new_from_cstring("abc");
    FAIL_UNLESS_EQUAL(dynstr_byte_at(dynstr, 1024), -1);
    return true;
}


static int test_byteat_reports_0xff_correctly(void)
{
    Dynstr *dynstr;
    
    dynstr = new_from_cstring("\xff");
    FAIL_UNLESS_EQUAL(dynstr_byte_at(dynstr, 0), 255);
    return true;
}


static int test_first_byte_finds_byte(void)
{
    Dynstr *dynstr;
    size_t offset;
    
    dynstr = new_from_cstring("123456");
    offset = dynstr_first_byte(dynstr, 0, '3');
    FAIL_UNLESS_EQUAL(offset, 2);
    return true;
}


static int test_first_byte_only_finds_first_byte(void)
{
    Dynstr *dynstr;
    size_t offset;
    
    dynstr = new_from_cstring("123123");
    offset = dynstr_first_byte(dynstr, 0, '3');
    FAIL_UNLESS_EQUAL(offset, 2);
    return true;
}


static int test_first_byte_does_not_find_nonexistent_byte(void)
{
    Dynstr *dynstr;
    size_t offset;
    
    dynstr = new_from_cstring("123456");
    offset = dynstr_first_byte(dynstr, 0, 'x');
    FAIL_UNLESS_EQUAL(offset, DYNSTR_NOT_FOUND);
    return true;
}


static int test_first_byte_does_not_find_byte_outside_range(void)
{
    Dynstr *dynstr;
    size_t offset;
    
    dynstr = new_from_cstring("123456");
    offset = dynstr_first_byte(dynstr, 4, '3');
    FAIL_UNLESS_EQUAL(offset, DYNSTR_NOT_FOUND);
    return true;
}


static int test_first_byte_only_finds_byte_inside_range(void)
{
    Dynstr *dynstr;
    size_t offset;
    
    dynstr = new_from_cstring("123123");
    offset = dynstr_first_byte(dynstr, 3, '3');
    FAIL_UNLESS_EQUAL(offset, 5);
    return true;
}


static int test_first_byte_does_not_find_in_range_outside_string(void)
{
    Dynstr *dynstr;
    size_t offset;
    
    dynstr = new_from_cstring("123123");
    offset = dynstr_first_byte(dynstr, 128, '3');
    FAIL_UNLESS_EQUAL(offset, DYNSTR_NOT_FOUND);
    return true;
}


static int test_last_byte_finds_byte(void)
{
    Dynstr *dynstr;
    size_t offset;
    
    dynstr = new_from_cstring("123456");
    offset = dynstr_last_byte(dynstr, 0, '3');
    FAIL_UNLESS_EQUAL(offset, 2);
    return true;
}


static int test_last_byte_only_finds_last_byte(void)
{
    Dynstr *dynstr;
    size_t offset;
    
    dynstr = new_from_cstring("123123");
    offset = dynstr_last_byte(dynstr, 0, '3');
    FAIL_UNLESS_EQUAL(offset, 5);
    return true;
}


static int test_last_byte_does_not_find_nonexistent_byte(void)
{
    Dynstr *dynstr;
    size_t offset;
    
    dynstr = new_from_cstring("123456");
    offset = dynstr_last_byte(dynstr, 0, 'x');
    FAIL_UNLESS_EQUAL(offset, DYNSTR_NOT_FOUND);
    return true;
}


static int test_last_byte_does_not_find_byte_outside_range(void)
{
    Dynstr *dynstr;
    size_t offset;
    
    dynstr = new_from_cstring("123456");
    offset = dynstr_last_byte(dynstr, 4, '3');
    FAIL_UNLESS_EQUAL(offset, DYNSTR_NOT_FOUND);
    return true;
}


static int test_last_byte_only_finds_byte_inside_range(void)
{
    Dynstr *dynstr;
    size_t offset;
    
    dynstr = new_from_cstring("123123");
    offset = dynstr_last_byte(dynstr, 3, '3');
    FAIL_UNLESS_EQUAL(offset, 5);
    return true;
}


static int test_last_byte_does_not_find_in_range_outside_string(void)
{
    Dynstr *dynstr;
    size_t offset;
    
    dynstr = new_from_cstring("123123");
    offset = dynstr_last_byte(dynstr, 128, '3');
    FAIL_UNLESS_EQUAL(offset, DYNSTR_NOT_FOUND);
    return true;
}


static int test_first_string_finds_pattern(void)
{
    Dynstr *dynstr;
    Dynstr *pattern;
    size_t offset;
    
    dynstr = new_from_cstring("123456");
    pattern = new_from_cstring("345");
    offset = dynstr_first_string(dynstr, 0, pattern);
    FAIL_UNLESS_EQUAL(offset, 2);
    return true;
}


static int test_first_string_only_finds_first_pattern(void)
{
    Dynstr *dynstr;
    Dynstr *pattern;
    size_t offset;
    
    dynstr = new_from_cstring("123123");
    pattern = new_from_cstring("123");
    offset = dynstr_first_string(dynstr, 0, pattern);
    FAIL_UNLESS_EQUAL(offset, 0);
    return true;
}


static int test_first_string_does_not_find_nonexistent_pattern(void)
{
    Dynstr *dynstr;
    Dynstr *pattern;
    size_t offset;
    
    dynstr = new_from_cstring("123456");
    pattern = new_from_cstring("x");
    offset = dynstr_first_string(dynstr, 0, pattern);
    FAIL_UNLESS_EQUAL(offset, DYNSTR_NOT_FOUND);
    return true;
}


static int test_first_string_does_not_find_pattern_outside_range(void)
{
    Dynstr *dynstr;
    Dynstr *pattern;
    size_t offset;
    
    dynstr = new_from_cstring("123456");
    pattern = new_from_cstring("123");
    offset = dynstr_first_string(dynstr, 3, pattern);
    FAIL_UNLESS_EQUAL(offset, DYNSTR_NOT_FOUND);
    return true;
}


static int test_first_string_only_finds_pattern_inside_range(void)
{
    Dynstr *dynstr;
    Dynstr *pattern;
    size_t offset;
    
    dynstr = new_from_cstring("123123");
    pattern = new_from_cstring("3");
    offset = dynstr_first_string(dynstr, 3, pattern);
    FAIL_UNLESS_EQUAL(offset, 5);
    return true;
}


static int test_first_string_does_not_find_empty_pattern(void)
{
    Dynstr *dynstr;
    Dynstr *pattern;
    size_t offset;
    
    dynstr = new_from_cstring("123123");
    pattern = new_from_cstring("");
    offset = dynstr_first_string(dynstr, 0, pattern);
    FAIL_UNLESS_EQUAL(offset, DYNSTR_NOT_FOUND);
    return true;
}


static int test_last_string_finds_pattern(void)
{
    Dynstr *dynstr;
    Dynstr *pattern;
    size_t offset;
    
    dynstr = new_from_cstring("123456");
    pattern = new_from_cstring("345");
    offset = dynstr_last_string(dynstr, 0, pattern);
    FAIL_UNLESS_EQUAL(offset, 2);
    return true;
}


static int test_last_string_only_finds_last_pattern(void)
{
    Dynstr *dynstr;
    Dynstr *pattern;
    size_t offset;
    
    dynstr = new_from_cstring("123123");
    pattern = new_from_cstring("123");
    offset = dynstr_last_string(dynstr, 0, pattern);
    FAIL_UNLESS_EQUAL(offset, 3);
    return true;
}


static int test_last_string_does_not_find_nonexistent_pattern(void)
{
    Dynstr *dynstr;
    Dynstr *pattern;
    size_t offset;
    
    dynstr = new_from_cstring("123456");
    pattern = new_from_cstring("x");
    offset = dynstr_last_string(dynstr, 0, pattern);
    FAIL_UNLESS_EQUAL(offset, DYNSTR_NOT_FOUND);
    return true;
}


static int test_last_string_does_not_find_pattern_outside_range(void)
{
    Dynstr *dynstr;
    Dynstr *pattern;
    size_t offset;
    
    dynstr = new_from_cstring("123456");
    pattern = new_from_cstring("123");
    offset = dynstr_last_string(dynstr, 3, pattern);
    FAIL_UNLESS_EQUAL(offset, DYNSTR_NOT_FOUND);
    return true;
}


static int test_last_string_only_finds_pattern_inside_range(void)
{
    Dynstr *dynstr;
    Dynstr *pattern;
    size_t offset;
    
    dynstr = new_from_cstring("123123");
    pattern = new_from_cstring("3");
    offset = dynstr_last_string(dynstr, 3, pattern);
    FAIL_UNLESS_EQUAL(offset, 5);
    return true;
}


static int test_last_string_does_not_find_empty_pattern(void)
{
    Dynstr *dynstr;
    Dynstr *pattern;
    size_t offset;
    
    dynstr = new_from_cstring("123123");
    pattern = new_from_cstring("");
    offset = dynstr_last_string(dynstr, 0, pattern);
    FAIL_UNLESS_EQUAL(offset, DYNSTR_NOT_FOUND);
    return true;
}

static int test_cmp_returns_0_for_equal_strings(void)
{
    Dynstr *a;
    Dynstr *b;
    
    a = new_from_cstring("foo");
    b = new_from_cstring("foo");
    FAIL_UNLESS_EQUAL(dynstr_cmp(a, b), 0);
    return true;
}


static int test_cmp_returns_0_for_empty_strings(void)
{
    Dynstr *a;
    Dynstr *b;
    
    a = dynstr_new_empty();
    b = dynstr_new_empty();
    FAIL_UNLESS_EQUAL(dynstr_cmp(a, b), 0);
    dynstr_free(a);
    dynstr_free(b);
    return true;
}


static int test_cmp_returns_negative_if_only_first_string_is_empty(void)
{
    Dynstr *a;
    Dynstr *b;
    
    a = new_from_cstring("");
    b = new_from_cstring("foo");
    FAIL_UNLESS(dynstr_cmp(a, b) < 0);
    return true;
}


static int test_cmp_returns_positive_if_only_second_string_is_empty(void)
{
    Dynstr *a;
    Dynstr *b;
    
    a = new_from_cstring("foo");
    b = new_from_cstring("");
    FAIL_UNLESS(dynstr_cmp(a, b) > 0);
    return true;
}


static int test_cmp_returns_negative_if_first_string_comes_first(void)
{
    Dynstr *a;
    Dynstr *b;
    
    a = new_from_cstring("x");
    b = new_from_cstring("\xff"); /* Check for unsigned comparision, too. */
    FAIL_UNLESS(dynstr_cmp(a, b) < 0);
    return true;
}


static int test_cmp_returns_positive_if_second_string_comes_first(void)
{
    Dynstr *a;
    Dynstr *b;
    
    a = new_from_cstring("\xff");
    b = new_from_cstring("x");
    FAIL_UNLESS(dynstr_cmp(a, b) > 0);
    return true;
}


static int write_test(long (*callback)(char *filename, Dynstr *dynstr))
{
    char tempname[] = "unittest.tmp.XXXXXX";
    int fd;
    size_t num_bytes;
    Dynstr *dynstr;
    Dynstr *dynstr2;
    char buf[1024];
    int read_bytes;
    
    dynstr = new_from_cstring("life is too short for str* and mem* in apps");
    
    fd = mkstemp(tempname);
    if (fd == -1)
        abort();

    num_bytes = callback(tempname, dynstr);

    FAIL_UNLESS_EQUAL(num_bytes, dynstr_len(dynstr));
    
    read_bytes = read(fd, buf, sizeof(buf));
    if (read_bytes == -1)
        abort();
    close(fd);
    remove(tempname);

    dynstr2 = dynstr_new_from_memory(buf, read_bytes);
    FAIL_UNLESS_EQUAL(read_bytes, dynstr_len(dynstr));
    FAIL_UNLESS_EQUAL(dynstr_cmp(dynstr, dynstr2), 0);
    dynstr_free(dynstr2);

    return true;
}


static long fwrite_callback(char *filename, Dynstr *dynstr)
{
    FILE *f;
    long num_bytes;
    
    f = fopen(filename, "w");
    num_bytes = dynstr_fwrite(f, dynstr);
    fclose(f);
    return num_bytes;
}


static int test_fwrite_writes_string(void)
{
    return write_test(fwrite_callback);
}


static long write_callback(char *filename, Dynstr *dynstr)
{
    int fd;
    long num_bytes;
    
    fd = open(filename, O_WRONLY, 0);
    num_bytes = dynstr_write(fd, dynstr);
    close(fd);
    return num_bytes;
}


static int test_write_writes_string(void)
{
    return write_test(write_callback);
}


static int read_test(Dynstr *(*callback)(char *filename, size_t size))
{
    char tempname[] = "unittest.tmp.XXXXXX";
    int fd;
    Dynstr *dynstr;
    Dynstr *dynstr2;
    const char canonical[] = "life is too short for str* and mem* in apps";
    
    fd = mkstemp(tempname);
    if (fd == -1)
        abort();
    if (write(fd, canonical, sizeof(canonical)) == -1)
        abort();
    close(fd);

    dynstr = callback(tempname, sizeof(canonical) * 2);
    remove(tempname);

    FAIL_UNLESS(dynstr != NULL);
    FAIL_UNLESS_EQUAL(dynstr_len(dynstr), sizeof(canonical));
    
    dynstr2 = dynstr_new_from_memory(canonical, sizeof(canonical));
    FAIL_UNLESS_EQUAL(dynstr_cmp(dynstr, dynstr2), 0);

    dynstr_free(dynstr);
    dynstr_free(dynstr2);

    return true;
}


static Dynstr *fread_callback(char *filename, size_t size)
{
    FILE *f;
    Dynstr *dynstr;
    
    f = fopen(filename, "r");
    dynstr = dynstr_fread(f, size);
    fclose(f);
    return dynstr;
}


static int test_fread_reads_string(void)
{
    return read_test(fread_callback);
}


static Dynstr *read_callback(char *filename, size_t size)
{
    int fd;
    Dynstr *dynstr;
    
    fd = open(filename, O_RDONLY, 0);
    dynstr = dynstr_read(fd, size);
    close(fd);
    return dynstr;
}


static int test_read_reads_string(void)
{
    return read_test(read_callback);
}


static int readline_test(Dynstr *(*callback)(char *filename))
{
    char tempname[] = "unittest.tmp.XXXXXX";
    int fd;
    const char cline1[] = "life is too short for str* and mem* in apps\n";
    const char cline2[] = "use dynstr instead!\n";
    Dynstr *lines;
    Dynstr *line1;
    Dynstr *line2;
    Dynstr *result;
    
    fd = mkstemp(tempname);
    if (fd == -1)
        abort();
        
    line1 = dynstr_new_from_constant_cstring(cline1);
    line2 = dynstr_new_from_constant_cstring(cline2);
    lines = dynstr_cat(line1, line2);
    if (dynstr_write(fd, lines) != dynstr_len(lines))
        abort();
    close(fd);
    
    result = callback(tempname);
    remove(tempname);

    FAIL_UNLESS_EQUAL(dynstr_cmp(line1, result), 0);

    dynstr_free(line1);
    dynstr_free(line2);
    dynstr_free(lines);
    dynstr_free(result);

    return true;
}


static Dynstr *freadline_callback(char *filename)
{
    FILE *f;
    Dynstr *line1;
    
    f = fopen(filename, "r");
    line1 = dynstr_freadline(f);
    fclose(f);
    return line1;
}


static int test_freadline_reads_first_line(void)
{
    return readline_test(freadline_callback);
}


static Dynstr *readline_callback(char *filename)
{
    int fd;
    Dynstr *line1;
    
    fd = open(filename, O_RDONLY, 0);
    line1 = dynstr_readline(fd);
    close(fd);
    return line1;
}


static int test_readline_reads_first_line(void)
{
    return readline_test(readline_callback);
}


static void setup(void)
{
    dynstr_init();
    fail_malloc_after = 0;
}


static void teardown(void)
{
    free_all_strings();
}


struct test {
    const char *name;
    int (*test)(void);
};


#define TEST(func) { #func, func }

static const struct test tests[] = {
    TEST(test_default_error_handler_is_indicate),
    TEST(test_sets_error_handler),
    TEST(test_init_resets_error_handler),
    TEST(test_uses_malloc_by_default),
    TEST(test_sets_malloc),
    TEST(test_init_resets_malloc),
    TEST(test_alloc_calls_error_handler),
    TEST(test_alloc_does_not_call_error_handler),
    TEST(test_indicate_handler_returns),
    TEST(test_abort_handler_calls_abort),
    TEST(test_empty_string_is_empty),
    TEST(test_new_returns_NULL_upon_first_allocation_failure),
    TEST(test_creates_from_cstring),
    TEST(test_creates_from_memory),
    TEST(test_creates_from_constant_cstring),
    TEST(test_creates_from_constant_memory),
    TEST(test_memcpy_returns_zero_if_offset_is_too_large),
    TEST(test_memcpy_truncates_if_copying_too_much),
    TEST(test_memcpy_copies_whole_string_ok),
    TEST(test_memcpy_copies_substring_ok),
    TEST(test_strdup_duplicates_string),
    TEST(test_copies_empty_substring_ok),
    TEST(test_copies_single_byte_substring_ok),
    TEST(test_copies_middle_substring_ok),
    TEST(test_copies_initial_substring_ok),
    TEST(test_copies_final_substring_ok),
    TEST(test_copies_empty_substring_when_offset_too_big),
    TEST(test_copies_partial_substring_when_length_too_big),
    TEST(test_cats_ok),
    TEST(test_cat_returns_NULL_for_first_malloc_failure),
    TEST(test_byteat_reports_correct_character),
    TEST(test_byteat_reports_error_for_too_large_offset),
    TEST(test_byteat_reports_0xff_correctly),
    TEST(test_first_byte_finds_byte),
    TEST(test_first_byte_only_finds_first_byte),
    TEST(test_first_byte_does_not_find_nonexistent_byte),
    TEST(test_first_byte_does_not_find_byte_outside_range),
    TEST(test_first_byte_only_finds_byte_inside_range),
    TEST(test_first_byte_does_not_find_in_range_outside_string),
    TEST(test_last_byte_finds_byte),
    TEST(test_last_byte_only_finds_last_byte),
    TEST(test_last_byte_does_not_find_nonexistent_byte),
    TEST(test_last_byte_does_not_find_byte_outside_range),
    TEST(test_last_byte_only_finds_byte_inside_range),
    TEST(test_last_byte_does_not_find_in_range_outside_string),
    TEST(test_first_string_finds_pattern),
    TEST(test_first_string_only_finds_first_pattern),
    TEST(test_first_string_does_not_find_nonexistent_pattern),
    TEST(test_first_string_does_not_find_pattern_outside_range),
    TEST(test_first_string_only_finds_pattern_inside_range),
    TEST(test_first_string_does_not_find_empty_pattern),
    TEST(test_last_string_finds_pattern),
    TEST(test_last_string_only_finds_last_pattern),
    TEST(test_last_string_does_not_find_nonexistent_pattern),
    TEST(test_last_string_does_not_find_pattern_outside_range),
    TEST(test_last_string_only_finds_pattern_inside_range),
    TEST(test_last_string_does_not_find_empty_pattern),
    TEST(test_cmp_returns_0_for_equal_strings),
    TEST(test_cmp_returns_0_for_empty_strings),
    TEST(test_cmp_returns_negative_if_only_first_string_is_empty),
    TEST(test_cmp_returns_positive_if_only_second_string_is_empty),
    TEST(test_cmp_returns_negative_if_first_string_comes_first),
    TEST(test_cmp_returns_positive_if_second_string_comes_first),
    TEST(test_fwrite_writes_string),
    TEST(test_write_writes_string),
    TEST(test_fread_reads_string),
    TEST(test_read_reads_string),
    TEST(test_freadline_reads_first_line),
    TEST(test_readline_reads_first_line),
};
static const int num_tests = sizeof(tests) / sizeof(tests[0]);

int main(void)
{
    int exit;

    exit = EXIT_SUCCESS;
    for (int i = 0; i < num_tests; ++i) {
        setup();
        if (!tests[i].test()) {
            exit = EXIT_FAILURE;
        }
        teardown();
    }
    return exit;
}