text: /* Copyright (c) 2014, Daniel Martí
   * Copyright (c) 2014, The Spider Project, Inc. */
  /* See LICENSE for licensing information */
  
  #define CONSDIFF_PRIVATE
  
  #include "or.h"
  #include "test.h"
  
  #include "consdiff.h"
  #include "memarea.h"
  #include "log_test_helpers.h"
  
  #define tt_str_eq_line(a,b) \
    tt_assert(line_str_eq((b),(a)))
  
  static void
  test_consdiff_smartlist_slice(void *arg)
  {
    smartlist_t *sl = smartlist_new();
    smartlist_slice_t *sls;
  
    /* Create a regular smartlist. */
    (void)arg;
    smartlist_add(sl, (void*)1);
    smartlist_add(sl, (void*)2);
    smartlist_add(sl, (void*)3);
    smartlist_add(sl, (void*)4);
    smartlist_add(sl, (void*)5);
  
    /* See if the slice was done correctly. */
    sls = smartlist_slice(sl, 2, 5);
    tt_ptr_op(sl, OP_EQ, sls->list);
    tt_ptr_op((void*)3, OP_EQ, smartlist_get(sls->list, sls->offset));
    tt_ptr_op((void*)5, OP_EQ,
        smartlist_get(sls->list, sls->offset + (sls->len-1)));
    spider_free(sls);
  
    /* See that using -1 as the end does get to the last element. */
    sls = smartlist_slice(sl, 2, -1);
    tt_ptr_op(sl, OP_EQ, sls->list);
    tt_ptr_op((void*)3, OP_EQ, smartlist_get(sls->list, sls->offset));
    tt_ptr_op((void*)5, OP_EQ,
        smartlist_get(sls->list, sls->offset + (sls->len-1)));
  
   done:
    spider_free(sls);
    smartlist_free(sl);
  }
  
  static void
  test_consdiff_smartlist_slice_string_pos(void *arg)
  {
    smartlist_t *sl = smartlist_new();
    smartlist_slice_t *sls;
    memarea_t *area = memarea_new();
  
    /* Create a regular smartlist. */
    (void)arg;
    consensus_split_lines(sl, "a\nd\nc\na\nb\n", area);
  
    /* See that smartlist_slice_string_pos respects the bounds of the slice. */
    sls = smartlist_slice(sl, 2, 5);
    cdline_t a_line = { "a", 1 };
    tt_int_op(3, OP_EQ, smartlist_slice_string_pos(sls, &a_line));
    cdline_t d_line = { "d", 1 };
    tt_int_op(-1, OP_EQ, smartlist_slice_string_pos(sls, &d_line));
  
   done:
    spider_free(sls);
    smartlist_free(sl);
    memarea_drop_all(area);
  }
  
  static void
  test_consdiff_lcs_lengths(void *arg)
  {
    smartlist_t *sl1 = smartlist_new();
    smartlist_t *sl2 = smartlist_new();
    smartlist_slice_t *sls1, *sls2;
    int *lengths1, *lengths2;
    memarea_t *area = memarea_new();
  
    /* Expected lcs lengths in regular and reverse order. */
    int e_lengths1[] = { 0, 1, 2, 3, 3, 4 };
    int e_lengths2[] = { 0, 1, 1, 2, 3, 4 };
  
    (void)arg;
    consensus_split_lines(sl1, "a\nb\nc\nd\ne\n", area);
    consensus_split_lines(sl2, "a\nc\nd\ni\ne\n", area);
  
    sls1 = smartlist_slice(sl1, 0, -1);
    sls2 = smartlist_slice(sl2, 0, -1);
  
    lengths1 = lcs_lengths(sls1, sls2, 1);
    lengths2 = lcs_lengths(sls1, sls2, -1);
    tt_mem_op(e_lengths1, OP_EQ, lengths1, sizeof(int) * 6);
    tt_mem_op(e_lengths2, OP_EQ, lengths2, sizeof(int) * 6);
  
   done:
    spider_free(lengths1);
    spider_free(lengths2);
    spider_free(sls1);
    spider_free(sls2);
    smartlist_free(sl1);
    smartlist_free(sl2);
    memarea_drop_all(area);
  }
  
  static void
  test_consdiff_trim_slices(void *arg)
  {
    smartlist_t *sl1 = smartlist_new();
    smartlist_t *sl2 = smartlist_new();
    smartlist_t *sl3 = smartlist_new();
    smartlist_t *sl4 = smartlist_new();
    smartlist_slice_t *sls1, *sls2, *sls3, *sls4;
    memarea_t *area = memarea_new();
  
    (void)arg;
    consensus_split_lines(sl1, "a\nb\nb\nb\nd\n", area);
    consensus_split_lines(sl2, "a\nc\nc\nc\nd\n", area);
    consensus_split_lines(sl3, "a\nb\nb\nb\na\n", area);
    consensus_split_lines(sl4, "c\nb\nb\nb\nc\n", area);
    sls1 = smartlist_slice(sl1, 0, -1);
    sls2 = smartlist_slice(sl2, 0, -1);
    sls3 = smartlist_slice(sl3, 0, -1);
    sls4 = smartlist_slice(sl4, 0, -1);
  
    /* They should be trimmed by one line at each end. */
    tt_int_op(5, OP_EQ, sls1->len);
    tt_int_op(5, OP_EQ, sls2->len);
    trim_slices(sls1, sls2);
    tt_int_op(3, OP_EQ, sls1->len);
    tt_int_op(3, OP_EQ, sls2->len);
  
    /* They should not be trimmed at all. */
    tt_int_op(5, OP_EQ, sls3->len);
    tt_int_op(5, OP_EQ, sls4->len);
    trim_slices(sls3, sls4);
    tt_int_op(5, OP_EQ, sls3->len);
    tt_int_op(5, OP_EQ, sls4->len);
  
   done:
    spider_free(sls1);
    spider_free(sls2);
    spider_free(sls3);
    spider_free(sls4);
    smartlist_free(sl1);
    smartlist_free(sl2);
    smartlist_free(sl3);
    smartlist_free(sl4);
    memarea_drop_all(area);
  }
  
  static void
  test_consdiff_set_changed(void *arg)
  {
    smartlist_t *sl1 = smartlist_new();
    smartlist_t *sl2 = smartlist_new();
    bitarray_t *changed1 = bitarray_init_zero(4);
    bitarray_t *changed2 = bitarray_init_zero(4);
    smartlist_slice_t *sls1, *sls2;
    memarea_t *area = memarea_new();
  
    (void)arg;
    consensus_split_lines(sl1, "a\nb\na\na\n", area);
    consensus_split_lines(sl2, "a\na\na\na\n", area);
  
    /* Length of sls1 is 0. */
    sls1 = smartlist_slice(sl1, 0, 0);
    sls2 = smartlist_slice(sl2, 1, 3);
    set_changed(changed1, changed2, sls1, sls2);
  
    /* The former is not changed, the latter changes all of its elements. */
    tt_assert(!bitarray_is_set(changed1, 0));
    tt_assert(!bitarray_is_set(changed1, 1));
    tt_assert(!bitarray_is_set(changed1, 2));
    tt_assert(!bitarray_is_set(changed1, 3));
  
    tt_assert(!bitarray_is_set(changed2, 0));
    tt_assert(bitarray_is_set(changed2, 1));
    tt_assert(bitarray_is_set(changed2, 2));
    tt_assert(!bitarray_is_set(changed2, 3));
    bitarray_clear(changed2, 1);
    bitarray_clear(changed2, 2);
  
    /* Length of sls1 is 1 and its element is in sls2. */
    spider_free(sls1);
    sls1 = smartlist_slice(sl1, 0, 1);
    set_changed(changed1, changed2, sls1, sls2);
  
    /* The latter changes all elements but the (first) common one. */
    tt_assert(!bitarray_is_set(changed1, 0));
    tt_assert(!bitarray_is_set(changed1, 1));
    tt_assert(!bitarray_is_set(changed1, 2));
    tt_assert(!bitarray_is_set(changed1, 3));
  
    tt_assert(!bitarray_is_set(changed2, 0));
    tt_assert(!bitarray_is_set(changed2, 1));
    tt_assert(bitarray_is_set(changed2, 2));
    tt_assert(!bitarray_is_set(changed2, 3));
    bitarray_clear(changed2, 2);
  
    /* Length of sls1 is 1 and its element is not in sls2. */
    spider_free(sls1);
    sls1 = smartlist_slice(sl1, 1, 2);
    set_changed(changed1, changed2, sls1, sls2);
  
    /* The former changes its element, the latter changes all elements. */
    tt_assert(!bitarray_is_set(changed1, 0));
    tt_assert(bitarray_is_set(changed1, 1));
    tt_assert(!bitarray_is_set(changed1, 2));
    tt_assert(!bitarray_is_set(changed1, 3));
  
    tt_assert(!bitarray_is_set(changed2, 0));
    tt_assert(bitarray_is_set(changed2, 1));
    tt_assert(bitarray_is_set(changed2, 2));
    tt_assert(!bitarray_is_set(changed2, 3));
  
   done:
    bitarray_free(changed1);
    bitarray_free(changed2);
    smartlist_free(sl1);
    smartlist_free(sl2);
    spider_free(sls1);
    spider_free(sls2);
    memarea_drop_all(area);
  }
  
  static void
  test_consdiff_calc_changes(void *arg)
  {
    smartlist_t *sl1 = smartlist_new();
    smartlist_t *sl2 = smartlist_new();
    smartlist_slice_t *sls1, *sls2;
    bitarray_t *changed1 = bitarray_init_zero(4);
    bitarray_t *changed2 = bitarray_init_zero(4);
    memarea_t *area = memarea_new();
  
    (void)arg;
    consensus_split_lines(sl1, "a\na\na\na\n", area);
    consensus_split_lines(sl2, "a\na\na\na\n", area);
  
    sls1 = smartlist_slice(sl1, 0, -1);
    sls2 = smartlist_slice(sl2, 0, -1);
    calc_changes(sls1, sls2, changed1, changed2);
  
    /* Nothing should be set to changed. */
    tt_assert(!bitarray_is_set(changed1, 0));
    tt_assert(!bitarray_is_set(changed1, 1));
    tt_assert(!bitarray_is_set(changed1, 2));
    tt_assert(!bitarray_is_set(changed1, 3));
  
    tt_assert(!bitarray_is_set(changed2, 0));
    tt_assert(!bitarray_is_set(changed2, 1));
    tt_assert(!bitarray_is_set(changed2, 2));
    tt_assert(!bitarray_is_set(changed2, 3));
  
    smartlist_clear(sl2);
    consensus_split_lines(sl2, "a\nb\na\nb\n", area);
    spider_free(sls1);
    spider_free(sls2);
    sls1 = smartlist_slice(sl1, 0, -1);
    sls2 = smartlist_slice(sl2, 0, -1);
    calc_changes(sls1, sls2, changed1, changed2);
  
    /* Two elements are changed. */
    tt_assert(!bitarray_is_set(changed1, 0));
    tt_assert(bitarray_is_set(changed1, 1));
    tt_assert(bitarray_is_set(changed1, 2));
    tt_assert(!bitarray_is_set(changed1, 3));
    bitarray_clear(changed1, 1);
    bitarray_clear(changed1, 2);
  
    tt_assert(!bitarray_is_set(changed2, 0));
    tt_assert(bitarray_is_set(changed2, 1));
    tt_assert(!bitarray_is_set(changed2, 2));
    tt_assert(bitarray_is_set(changed2, 3));
    bitarray_clear(changed1, 1);
    bitarray_clear(changed1, 3);
  
    smartlist_clear(sl2);
    consensus_split_lines(sl2, "b\nb\nb\nb\n", area);
    spider_free(sls1);
    spider_free(sls2);
    sls1 = smartlist_slice(sl1, 0, -1);
    sls2 = smartlist_slice(sl2, 0, -1);
    calc_changes(sls1, sls2, changed1, changed2);
  
    /* All elements are changed. */
    tt_assert(bitarray_is_set(changed1, 0));
    tt_assert(bitarray_is_set(changed1, 1));
    tt_assert(bitarray_is_set(changed1, 2));
    tt_assert(bitarray_is_set(changed1, 3));
  
    tt_assert(bitarray_is_set(changed2, 0));
    tt_assert(bitarray_is_set(changed2, 1));
    tt_assert(bitarray_is_set(changed2, 2));
    tt_assert(bitarray_is_set(changed2, 3));
  
   done:
    bitarray_free(changed1);
    bitarray_free(changed2);
    smartlist_free(sl1);
    smartlist_free(sl2);
    spider_free(sls1);
    spider_free(sls2);
    memarea_drop_all(area);
  }
  
  static void
  test_consdiff_get_id_hash(void *arg)
  {
    (void)arg;
  
    cdline_t line1 = { "r name", 6 };
    cdline_t line2 = { "r name _hash_isnt_base64 etc", 28 };
    cdline_t line3 = { "r name hash+valid+base64 etc", 28 };
    cdline_t tmp;
  
    /* No hash. */
    tt_int_op(-1, OP_EQ, get_id_hash(&line1, &tmp));
    /* The hash contains characters that are not base64. */
    tt_int_op(-1, OP_EQ, get_id_hash(&line2, &tmp));
  
    /* valid hash. */
    tt_int_op(0, OP_EQ, get_id_hash(&line3, &tmp));
    tt_ptr_op(tmp.s, OP_EQ, line3.s + 7);
    tt_uint_op(tmp.len, OP_EQ, line3.len - 11);
  
   done:
    ;
  }
  
  static void
  test_consdiff_is_valid_router_entry(void *arg)
  {
    /* Doesn't start with "r ". */
    (void)arg;
    cdline_t line0 = { "foo", 3 };
    tt_int_op(0, OP_EQ, is_valid_router_entry(&line0));
  
    /* These are already tested with get_id_hash, but make sure it's run
     * properly. */
  
    cdline_t line1 = { "r name", 6 };
    cdline_t line2 = { "r name _hash_isnt_base64 etc", 28 };
    cdline_t line3 = { "r name hash+valid+base64 etc", 28 };
    tt_int_op(0, OP_EQ, is_valid_router_entry(&line1));
    tt_int_op(0, OP_EQ, is_valid_router_entry(&line2));
    tt_int_op(1, OP_EQ, is_valid_router_entry(&line3));
  
   done:
    ;
  }
  
  static void
  test_consdiff_next_router(void *arg)
  {
    smartlist_t *sl = smartlist_new();
    memarea_t *area = memarea_new();
    (void)arg;
    smartlist_add_linecpy(sl, area, "foo");
    smartlist_add_linecpy(sl, area,
        "r name hash+longer+than+27+chars+and+valid+base64 etc");
    smartlist_add_linecpy(sl, area, "foo");
    smartlist_add_linecpy(sl, area, "foo");
    smartlist_add_linecpy(sl, area,
        "r name hash+longer+than+27+chars+and+valid+base64 etc");
    smartlist_add_linecpy(sl, area, "foo");
  
    /* Not currently on a router entry line, finding the next one. */
    tt_int_op(1, OP_EQ, next_router(sl, 0));
    tt_int_op(4, OP_EQ, next_router(sl, 2));
  
    /* Already at the beginning of a router entry line, ignore it. */
    tt_int_op(4, OP_EQ, next_router(sl, 1));
  
    /* There are no more router entries, so return the line after the last. */
    tt_int_op(6, OP_EQ, next_router(sl, 4));
    tt_int_op(6, OP_EQ, next_router(sl, 5));
  
   done:
    smartlist_free(sl);
    memarea_drop_all(area);
  }
  
  static int
  base64cmp_wrapper(const char *a, const char *b)
  {
    cdline_t aa = { a, a ? (uint32_t) strlen(a) : 0 };
    cdline_t bb = { b, b ? (uint32_t) strlen(b) : 0 };
    return base64cmp(&aa, &bb);
  }
  
  static void
  test_consdiff_base64cmp(void *arg)
  {
    /* NULL arguments. */
    (void)arg;
    tt_int_op(0, OP_EQ, base64cmp_wrapper(NULL, NULL));
    tt_int_op(-1, OP_EQ, base64cmp_wrapper(NULL, "foo"));
    tt_int_op(1, OP_EQ, base64cmp_wrapper("bar", NULL));
  
    /* Nil base64 values. */
    tt_int_op(0, OP_EQ, base64cmp_wrapper("", ""));
    tt_int_op(0, OP_EQ, base64cmp_wrapper("_", "&"));
  
    /* Exact same valid strings. */
    tt_int_op(0, OP_EQ, base64cmp_wrapper("abcABC/+", "abcABC/+"));
    /* Both end with an invalid base64 char other than '\0'. */
    tt_int_op(0, OP_EQ, base64cmp_wrapper("abcABC/+ ", "abcABC/+ "));
    /* Only one ends with an invalid base64 char other than '\0'. */
    tt_int_op(-1, OP_EQ, base64cmp_wrapper("abcABC/+ ", "abcABC/+a"));
  
    /* Comparisons that would return differently with strcmp(). */
    tt_int_op(-1, OP_EQ, strcmp("/foo", "Afoo"));
    tt_int_op(1, OP_EQ, base64cmp_wrapper("/foo", "Afoo"));
    tt_int_op(1, OP_EQ, strcmp("Afoo", "0foo"));
    tt_int_op(-1, OP_EQ, base64cmp_wrapper("Afoo", "0foo"));
  
    /* Comparisons that would return the same as with strcmp(). */
    tt_int_op(1, OP_EQ, strcmp("afoo", "Afoo"));
    tt_int_op(1, OP_EQ, base64cmp_wrapper("afoo", "Afoo"));
  
    /* Different lengths */
    tt_int_op(-1, OP_EQ, base64cmp_wrapper("afoo", "afooo"));
    tt_int_op(1, OP_EQ, base64cmp_wrapper("afooo", "afoo"));
  
   done:
    ;
  }
  
  static void
  test_consdiff_gen_ed_diff(void *arg)
  {
    smartlist_t *cons1=NULL, *cons2=NULL, *diff=NULL;
    int i;
    memarea_t *area = memarea_new();
    setup_capture_of_logs(LOG_WARN);
  
    (void)arg;
    cons1 = smartlist_new();
    cons2 = smartlist_new();
  
    /* Identity hashes are not sorted properly, return NULL. */
    smartlist_add_linecpy(cons1, area, "r name bbbbbbbbbbbbbbbbbbbbbbbbbbb etc");
    smartlist_add_linecpy(cons1, area, "foo");
    smartlist_add_linecpy(cons1, area, "r name aaaaaaaaaaaaaaaaaaaaaaaaaaa etc");
    smartlist_add_linecpy(cons1, area, "bar");
  
    smartlist_add_linecpy(cons2, area, "r name aaaaaaaaaaaaaaaaaaaaaaaaaaa etc");
    smartlist_add_linecpy(cons2, area, "foo");
    smartlist_add_linecpy(cons2, area, "r name ccccccccccccccccccccccccccc etc");
    smartlist_add_linecpy(cons2, area, "bar");
  
    diff = gen_ed_diff(cons1, cons2, area);
    tt_ptr_op(NULL, OP_EQ, diff);
    expect_single_log_msg_containing("Refusing to generate consensus diff "
           "because the base consensus doesn't have its router entries sorted "
           "properly.");
  
    /* Same, but now with the second consensus. */
    mock_clean_saved_logs();
    diff = gen_ed_diff(cons2, cons1, area);
    tt_ptr_op(NULL, OP_EQ, diff);
    expect_single_log_msg_containing("Refusing to generate consensus diff "
           "because the target consensus doesn't have its router entries sorted "
           "properly.");
  
    /* Same as the two above, but with the reversed thing immediately after a
       match. (The code handles this differently) */
    smartlist_del(cons1, 0);
    smartlist_add_linecpy(cons1, area, "r name aaaaaaaaaaaaaaaaaaaaaaaaaaa etc");
  
    mock_clean_saved_logs();
    diff = gen_ed_diff(cons1, cons2, area);
    tt_ptr_op(NULL, OP_EQ, diff);
    expect_single_log_msg_containing("Refusing to generate consensus diff "
           "because the base consensus doesn't have its router entries sorted "
           "properly.");
  
    mock_clean_saved_logs();
    diff = gen_ed_diff(cons2, cons1, area);
    tt_ptr_op(NULL, OP_EQ, diff);
    expect_single_log_msg_containing("Refusing to generate consensus diff "
           "because the target consensus doesn't have its router entries sorted "
           "properly.");
  
    /* Identity hashes are repeated, return NULL. */
    smartlist_clear(cons1);
  
    smartlist_add_linecpy(cons1, area, "r name bbbbbbbbbbbbbbbbbbbbbbbbbbb etc");
    smartlist_add_linecpy(cons1, area, "foo");
    smartlist_add_linecpy(cons1, area, "r name bbbbbbbbbbbbbbbbbbbbbbbbbbb etc");
    smartlist_add_linecpy(cons1, area, "bar");
  
    mock_clean_saved_logs();
    diff = gen_ed_diff(cons1, cons2, area);
    tt_ptr_op(NULL, OP_EQ, diff);
    expect_single_log_msg_containing("Refusing to generate consensus diff "
           "because the base consensus doesn't have its router entries sorted "
           "properly.");
  
    /* We have to add a line that is just a dot, return NULL. */
    smartlist_clear(cons1);
    smartlist_clear(cons2);
  
    smartlist_add_linecpy(cons1, area, "foo1");
    smartlist_add_linecpy(cons1, area, "foo2");
  
    smartlist_add_linecpy(cons2, area, "foo1");
    smartlist_add_linecpy(cons2, area, ".");
    smartlist_add_linecpy(cons2, area, "foo2");
  
    mock_clean_saved_logs();
    diff = gen_ed_diff(cons1, cons2, area);
    tt_ptr_op(NULL, OP_EQ, diff);
    expect_single_log_msg_containing("Cannot generate consensus diff "
           "because one of the lines to be added is \".\".");
  
  #define MAX_LINE_COUNT (10000)
    /* Too many lines to be fed to the quadratic-time function. */
    smartlist_clear(cons1);
    smartlist_clear(cons2);
  
    for (i=0; i < MAX_LINE_COUNT; ++i) smartlist_add_linecpy(cons1, area, "a");
    for (i=0; i < MAX_LINE_COUNT; ++i) smartlist_add_linecpy(cons1, area, "b");
  
    mock_clean_saved_logs();
    diff = gen_ed_diff(cons1, cons2, area);
  
    tt_ptr_op(NULL, OP_EQ, diff);
    expect_single_log_msg_containing("Refusing to generate consensus diff "
           "because we found too few common router ids.");
  
    /* We have dot lines, but they don't interfere with the script format. */
    smartlist_clear(cons1);
    smartlist_clear(cons2);
  
    smartlist_add_linecpy(cons1, area, "foo1");
    smartlist_add_linecpy(cons1, area, ".");
    smartlist_add_linecpy(cons1, area, ".");
    smartlist_add_linecpy(cons1, area, "foo2");
  
    smartlist_add_linecpy(cons2, area, "foo1");
    smartlist_add_linecpy(cons2, area, ".");
    smartlist_add_linecpy(cons2, area, "foo2");
  
    diff = gen_ed_diff(cons1, cons2, area);
    tt_ptr_op(NULL, OP_NE, diff);
    smartlist_free(diff);
  
    /* Empty diff tests. */
    smartlist_clear(cons1);
    smartlist_clear(cons2);
  
    diff = gen_ed_diff(cons1, cons2, area);
    tt_ptr_op(NULL, OP_NE, diff);
    tt_int_op(0, OP_EQ, smartlist_len(diff));
    smartlist_free(diff);
  
    smartlist_add_linecpy(cons1, area, "foo");
    smartlist_add_linecpy(cons1, area, "bar");
  
    smartlist_add_linecpy(cons2, area, "foo");
    smartlist_add_linecpy(cons2, area, "bar");
  
    diff = gen_ed_diff(cons1, cons2, area);
    tt_ptr_op(NULL, OP_NE, diff);
    tt_int_op(0, OP_EQ, smartlist_len(diff));
    smartlist_free(diff);
  
    /* Everything is deleted. */
    smartlist_clear(cons2);
  
    diff = gen_ed_diff(cons1, cons2, area);
    tt_ptr_op(NULL, OP_NE, diff);
    tt_int_op(1, OP_EQ, smartlist_len(diff));
    tt_str_eq_line("1,2d", smartlist_get(diff, 0));
  
    smartlist_free(diff);
  
    /* Everything is added. */
    diff = gen_ed_diff(cons2, cons1, area);
    tt_ptr_op(NULL, OP_NE, diff);
    tt_int_op(4, OP_EQ, smartlist_len(diff));
    tt_str_eq_line("0a", smartlist_get(diff, 0));
    tt_str_eq_line("foo", smartlist_get(diff, 1));
    tt_str_eq_line("bar", smartlist_get(diff, 2));
    tt_str_eq_line(".", smartlist_get(diff, 3));
  
    smartlist_free(diff);
  
    /* Everything is changed. */
    smartlist_add_linecpy(cons2, area, "foo2");
    smartlist_add_linecpy(cons2, area, "bar2");
    diff = gen_ed_diff(cons1, cons2, area);
    tt_ptr_op(NULL, OP_NE, diff);
    tt_int_op(4, OP_EQ, smartlist_len(diff));
    tt_str_eq_line("1,2c", smartlist_get(diff, 0));
    tt_str_eq_line("foo2", smartlist_get(diff, 1));
    tt_str_eq_line("bar2", smartlist_get(diff, 2));
    tt_str_eq_line(".", smartlist_get(diff, 3));
  
    smartlist_free(diff);
  
    /* Test 'a', 'c' and 'd' together. See that it is done in reverse order. */
    smartlist_clear(cons1);
    smartlist_clear(cons2);
    consensus_split_lines(cons1, "A\nB\nC\nD\nE\n", area);
    consensus_split_lines(cons2, "A\nC\nO\nE\nU\n", area);
    diff = gen_ed_diff(cons1, cons2, area);
    tt_ptr_op(NULL, OP_NE, diff);
    tt_int_op(7, OP_EQ, smartlist_len(diff));
    tt_str_eq_line("5a", smartlist_get(diff, 0));
    tt_str_eq_line("U", smartlist_get(diff, 1));
    tt_str_eq_line(".", smartlist_get(diff, 2));
    tt_str_eq_line("4c", smartlist_get(diff, 3));
    tt_str_eq_line("O", smartlist_get(diff, 4));
    tt_str_eq_line(".", smartlist_get(diff, 5));
    tt_str_eq_line("2d", smartlist_get(diff, 6));
  
    /* TODO: small real use-cases, i.e. consensuses. */
  
   done:
    teardown_capture_of_logs();
    smartlist_free(cons1);
    smartlist_free(cons2);
    smartlist_free(diff);
    memarea_drop_all(area);
  }
  
  static void
  test_consdiff_apply_ed_diff(void *arg)
  {
    smartlist_t *cons1=NULL, *cons2=NULL, *diff=NULL;
    memarea_t *area = memarea_new();
    (void)arg;
    cons1 = smartlist_new();
    diff = smartlist_new();
    setup_capture_of_logs(LOG_WARN);
  
    consensus_split_lines(cons1, "A\nB\nC\nD\nE\n", area);
  
    /* Command without range. */
    smartlist_add_linecpy(diff, area, "a");
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_EQ, cons2);
    smartlist_clear(diff);
    expect_single_log_msg_containing("an ed command was missing a line number");
  
    /* Range without command. */
    smartlist_add_linecpy(diff, area, "1");
    mock_clean_saved_logs();
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("a line with no ed command was found");
  
    smartlist_clear(diff);
  
    /* Range without end. */
    smartlist_add_linecpy(diff, area, "1,");
    mock_clean_saved_logs();
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("an ed command was missing a range "
                                     "end line number.");
  
    smartlist_clear(diff);
  
    /* Incoherent ranges. */
    smartlist_add_linecpy(diff, area, "1,1");
    mock_clean_saved_logs();
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("an invalid range was found");
  
    smartlist_clear(diff);
  
    smartlist_add_linecpy(diff, area, "3,2");
    mock_clean_saved_logs();
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("an invalid range was found");
  
    smartlist_clear(diff);
  
    /* Script is not in reverse order. */
    smartlist_add_linecpy(diff, area, "1d");
    smartlist_add_linecpy(diff, area, "3d");
    mock_clean_saved_logs();
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("its commands are not properly sorted");
  
    smartlist_clear(diff);
  
    /* Script contains unrecognised commands longer than one char. */
    smartlist_add_linecpy(diff, area, "1foo");
    mock_clean_saved_logs();
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("an ed command longer than one char was "
                                     "found");
  
    smartlist_clear(diff);
  
    /* Script contains unrecognised commands. */
    smartlist_add_linecpy(diff, area, "1e");
    mock_clean_saved_logs();
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("an unrecognised ed command was found");
  
    smartlist_clear(diff);
  
    /* Command that should be followed by at least one line and a ".", but
     * isn't. */
    smartlist_add_linecpy(diff, area, "0a");
    mock_clean_saved_logs();
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("it has an ed command that tries to "
                                     "insert zero lines.");
  
    /* Now it is followed by a ".", but it inserts zero lines. */
    smartlist_add_linecpy(diff, area, ".");
    mock_clean_saved_logs();
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("it has an ed command that tries to "
                                     "insert zero lines.");
  
    smartlist_clear(diff);
  
    /* Now it it inserts something, but has no terminaspider. */
    smartlist_add_linecpy(diff, area, "0a");
    smartlist_add_linecpy(diff, area, "hello");
    mock_clean_saved_logs();
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("lines to be inserted that don't end with "
                                     "a \".\".");
  
    smartlist_clear(diff);
  
    /* Test appending text, 'a'. */
    consensus_split_lines(diff, "3a\nU\nO\n.\n0a\nV\n.\n", area);
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_NE, cons2);
    tt_int_op(8, OP_EQ, smartlist_len(cons2));
    tt_str_eq_line("V", smartlist_get(cons2, 0));
    tt_str_eq_line("A", smartlist_get(cons2, 1));
    tt_str_eq_line("B", smartlist_get(cons2, 2));
    tt_str_eq_line("C", smartlist_get(cons2, 3));
    tt_str_eq_line("U", smartlist_get(cons2, 4));
    tt_str_eq_line("O", smartlist_get(cons2, 5));
    tt_str_eq_line("D", smartlist_get(cons2, 6));
    tt_str_eq_line("E", smartlist_get(cons2, 7));
  
    smartlist_clear(diff);
    smartlist_free(cons2);
  
    /* Test deleting text, 'd'. */
    consensus_split_lines(diff, "4d\n1,2d\n", area);
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_NE, cons2);
    tt_int_op(2, OP_EQ, smartlist_len(cons2));
    tt_str_eq_line("C", smartlist_get(cons2, 0));
    tt_str_eq_line("E", smartlist_get(cons2, 1));
  
    smartlist_clear(diff);
    smartlist_free(cons2);
  
    /* Test changing text, 'c'. */
    consensus_split_lines(diff, "4c\nT\nX\n.\n1, 2c\nM\n.\n", area);
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_NE, cons2);
    tt_int_op(5, OP_EQ, smartlist_len(cons2));
    tt_str_eq_line("M", smartlist_get(cons2, 0));
    tt_str_eq_line("C", smartlist_get(cons2, 1));
    tt_str_eq_line("T", smartlist_get(cons2, 2));
    tt_str_eq_line("X", smartlist_get(cons2, 3));
    tt_str_eq_line("E", smartlist_get(cons2, 4));
  
    smartlist_clear(diff);
    smartlist_free(cons2);
  
    /* Test 'a', 'd' and 'c' together. */
    consensus_split_lines(diff, "4c\nT\nX\n.\n2d\n0a\nM\n.\n", area);
    cons2 = apply_ed_diff(cons1, diff, 0);
    tt_ptr_op(NULL, OP_NE, cons2);
    tt_int_op(6, OP_EQ, smartlist_len(cons2));
    tt_str_eq_line("M", smartlist_get(cons2, 0));
    tt_str_eq_line("A", smartlist_get(cons2, 1));
    tt_str_eq_line("C", smartlist_get(cons2, 2));
    tt_str_eq_line("T", smartlist_get(cons2, 3));
    tt_str_eq_line("X", smartlist_get(cons2, 4));
    tt_str_eq_line("E", smartlist_get(cons2, 5));
  
   done:
    teardown_capture_of_logs();
    smartlist_free(cons1);
    smartlist_free(cons2);
    smartlist_free(diff);
    memarea_drop_all(area);
  }
  
  static void
  test_consdiff_gen_diff(void *arg)
  {
    char *cons1_str=NULL, *cons2_str=NULL;
    smartlist_t *cons1=NULL, *cons2=NULL, *diff=NULL;
    consensus_digest_t digests1, digests2;
    memarea_t *area = memarea_new();
    (void)arg;
    cons1 = smartlist_new();
    cons2 = smartlist_new();
  
    /* Identity hashes are not sorted properly, return NULL.
     * Already tested in gen_ed_diff, but see that a NULL ed diff also makes
     * gen_diff return NULL. */
    cons1_str = spider_strdup(
        "network-status-version foo\n"
        "r name bbbbbbbbbbbbbbbbb etc\nfoo\n"
        "r name aaaaaaaaaaaaaaaaa etc\nbar\n"
        "directory-signature foo bar\nbar\n"
        );
    cons2_str = spider_strdup(
        "network-status-version foo\n"
        "r name aaaaaaaaaaaaaaaaa etc\nfoo\n"
        "r name ccccccccccccccccc etc\nbar\n"
        "directory-signature foo bar\nbar\n"
        );
  
    tt_int_op(0, OP_EQ,
        consensus_compute_digest(cons1_str, &digests1));
    tt_int_op(0, OP_EQ,
        consensus_compute_digest(cons2_str, &digests2));
  
    consensus_split_lines(cons1, cons1_str, area);
    consensus_split_lines(cons2, cons2_str, area);
  
    diff = consdiff_gen_diff(cons1, cons2, &digests1, &digests2, area);
    tt_ptr_op(NULL, OP_EQ, diff);
  
    /* Check that the headers are done properly. */
    spider_free(cons1_str);
    cons1_str = spider_strdup(
        "network-status-version foo\n"
        "r name ccccccccccccccccc etc\nfoo\n"
        "r name eeeeeeeeeeeeeeeee etc\nbar\n"
        "directory-signature foo bar\nbar\n"
        );
    tt_int_op(0, OP_EQ,
        consensus_compute_digest(cons1_str, &digests1));
    smartlist_clear(cons1);
    consensus_split_lines(cons1, cons1_str, area);
    diff = consdiff_gen_diff(cons1, cons2, &digests1, &digests2, area);
    tt_ptr_op(NULL, OP_NE, diff);
    tt_int_op(7, OP_EQ, smartlist_len(diff));
    tt_assert(line_str_eq(smartlist_get(diff, 0),
                          "network-status-diff-version 1"));
    tt_assert(line_str_eq(smartlist_get(diff, 1), "hash "
        "06646D6CF563A41869D3B02E73254372AE3140046C5E7D83C9F71E54976AF9B4 "
        "7AFECEFA4599BA33D603653E3D2368F648DF4AC4723929B0F7CF39281596B0C1"));
    tt_assert(line_str_eq(smartlist_get(diff, 2), "3,4d"));
    tt_assert(line_str_eq(smartlist_get(diff, 3), "1a"));
    tt_assert(line_str_eq(smartlist_get(diff, 4),
                          "r name aaaaaaaaaaaaaaaaa etc"));
    tt_assert(line_str_eq(smartlist_get(diff, 5), "foo"));
    tt_assert(line_str_eq(smartlist_get(diff, 6), "."));
  
    /* TODO: small real use-cases, i.e. consensuses. */
  
   done:
    spider_free(cons1_str);
    spider_free(cons2_str);
    smartlist_free(cons1);
    smartlist_free(cons2);
    smartlist_free(diff);
    memarea_drop_all(area);
  }
  
  static void
  test_consdiff_apply_diff(void *arg)
  {
    smartlist_t *cons1=NULL, *diff=NULL;
    char *cons1_str=NULL, *cons2 = NULL;
    consensus_digest_t digests1;
    (void)arg;
    memarea_t *area = memarea_new();
    cons1 = smartlist_new();
    diff = smartlist_new();
    setup_capture_of_logs(LOG_INFO);
  
    cons1_str = spider_strdup(
        "network-status-version foo\n"
        "r name ccccccccccccccccc etc\nfoo\n"
        "r name eeeeeeeeeeeeeeeee etc\nbar\n"
        "directory-signature foo bar\nbar\n"
        );
    tt_int_op(0, OP_EQ,
        consensus_compute_digest(cons1_str, &digests1));
    consensus_split_lines(cons1, cons1_str, area);
  
    /* diff doesn't have enough lines. */
    cons2 = consdiff_apply_diff(cons1, diff, &digests1);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("too short")
  
    /* first line doesn't match format-version string. */
    smartlist_add_linecpy(diff, area, "foo-bar");
    smartlist_add_linecpy(diff, area, "header-line");
    mock_clean_saved_logs();
    cons2 = consdiff_apply_diff(cons1, diff, &digests1);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("format is not known")
  
    /* The first word of the second header line is not "hash". */
    smartlist_clear(diff);
    smartlist_add_linecpy(diff, area, "network-status-diff-version 1");
    smartlist_add_linecpy(diff, area, "word a b");
    smartlist_add_linecpy(diff, area, "x");
    mock_clean_saved_logs();
    cons2 = consdiff_apply_diff(cons1, diff, &digests1);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("does not include the necessary digests")
  
    /* Wrong number of words after "hash". */
    smartlist_clear(diff);
    smartlist_add_linecpy(diff, area, "network-status-diff-version 1");
    smartlist_add_linecpy(diff, area, "hash a b c");
    mock_clean_saved_logs();
    cons2 = consdiff_apply_diff(cons1, diff, &digests1);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("does not include the necessary digests")
  
    /* base16 digests do not have the expected length. */
    smartlist_clear(diff);
    smartlist_add_linecpy(diff, area, "network-status-diff-version 1");
    smartlist_add_linecpy(diff, area, "hash aaa bbb");
    mock_clean_saved_logs();
    cons2 = consdiff_apply_diff(cons1, diff, &digests1);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("includes base16-encoded digests of "
                                     "incorrect size")
  
    /* base16 digests contain non-base16 characters. */
    smartlist_clear(diff);
    smartlist_add_linecpy(diff, area, "network-status-diff-version 1");
    smartlist_add_linecpy(diff, area, "hash"
        " ????????????????????????????????????????????????????????????????"
        " ----------------------------------------------------------------");
    mock_clean_saved_logs();
    cons2 = consdiff_apply_diff(cons1, diff, &digests1);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("includes malformed digests")
  
    /* Invalid ed diff.
     * As tested in apply_ed_diff, but check that apply_diff does return NULL if
     * the ed diff can't be applied. */
    smartlist_clear(diff);
    smartlist_add_linecpy(diff, area, "network-status-diff-version 1");
    smartlist_add_linecpy(diff, area, "hash"
        /* sha3 of cons1. */
        " 06646D6CF563A41869D3B02E73254372AE3140046C5E7D83C9F71E54976AF9B4"
        /* sha256 of cons2. */
        " 635D34593020C08E5ECD865F9986E29D50028EFA62843766A8197AD228A7F6AA");
    smartlist_add_linecpy(diff, area, "foobar");
    mock_clean_saved_logs();
    cons2 = consdiff_apply_diff(cons1, diff, &digests1);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_single_log_msg_containing("because an ed command was missing a line "
                                     "number")
  
    /* Base consensus doesn't match its digest as found in the diff. */
    smartlist_clear(diff);
    smartlist_add_linecpy(diff, area, "network-status-diff-version 1");
    smartlist_add_linecpy(diff, area, "hash"
        /* bogus sha256. */
        " 3333333333333333333333333333333333333333333333333333333333333333"
        /* sha256 of cons2. */
        " 635D34593020C08E5ECD865F9986E29D50028EFA62843766A8197AD228A7F6AA");
    mock_clean_saved_logs();
    cons2 = consdiff_apply_diff(cons1, diff, &digests1);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_log_msg_containing("base consensus doesn't match the digest "
                              "as found");
  
    /* Resulting consensus doesn't match its digest as found in the diff. */
    smartlist_clear(diff);
    smartlist_add_linecpy(diff, area, "network-status-diff-version 1");
    smartlist_add_linecpy(diff, area, "hash"
        /* sha3 of cons1. */
        " 06646D6CF563A41869D3B02E73254372AE3140046C5E7D83C9F71E54976AF9B4"
        /* bogus sha3. */
        " 3333333333333333333333333333333333333333333333333333333333333333");
    mock_clean_saved_logs();
    cons2 = consdiff_apply_diff(cons1, diff, &digests1);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_log_msg_containing("resulting consensus doesn't match the "
                              "digest as found");
  
  #if 0
    /* XXXX No longer possible, since we aren't using the other algorithm. */
    /* Resulting consensus digest cannot be computed */
    smartlist_clear(diff);
    smartlist_add_linecpy(diff, area, "network-status-diff-version 1");
    smartlist_add_linecpy(diff, area, "hash"
        /* sha3 of cons1. */
        " 06646D6CF563A41869D3B02E73254372AE3140046C5E7D83C9F71E54976AF9B4"
        /* bogus sha3. */
        " 3333333333333333333333333333333333333333333333333333333333333333");
    smartlist_add_linecpy(diff, area, "1,2d"); // remove starting line
    mock_clean_saved_logs();
    cons2 = consdiff_apply_diff(cons1, diff, &digests1);
    tt_ptr_op(NULL, OP_EQ, cons2);
    expect_log_msg_containing("Could not compute digests of the consensus "
                              "resulting from applying a consensus diff.");
  #endif
  
    /* Very simple test, only to see that nothing errors. */
    smartlist_clear(diff);
    smartlist_add_linecpy(diff, area, "network-status-diff-version 1");
    smartlist_add_linecpy(diff, area, "hash"
        /* sha3 of cons1. */
        " 06646D6CF563A41869D3B02E73254372AE3140046C5E7D83C9F71E54976AF9B4"
        /* sha3 of cons2. */
        " 90A418881B2FCAB3D9E60EE02E4D666D56CFA38F8A3B7AA3E0ADBA530DDA9353");
    smartlist_add_linecpy(diff, area, "3c");
    smartlist_add_linecpy(diff, area, "sample");
    smartlist_add_linecpy(diff, area, ".");
    cons2 = consdiff_apply_diff(cons1, diff, &digests1);
    tt_ptr_op(NULL, OP_NE, cons2);
    tt_str_op(
        "network-status-version foo\n"
        "r name ccccccccccccccccc etc\nsample\n"
        "r name eeeeeeeeeeeeeeeee etc\nbar\n"
        "directory-signature foo bar\nbar\n", OP_EQ,
        cons2);
    spider_free(cons2);
  
    /* Check that lowercase letters in base16-encoded digests work too. */
    smartlist_clear(diff);
    smartlist_add_linecpy(diff, area, "network-status-diff-version 1");
    smartlist_add_linecpy(diff, area, "hash"
        /* sha3 of cons1. */
        " 06646d6cf563a41869d3b02e73254372ae3140046c5e7d83c9f71e54976af9b4"
        /* sha3 of cons2. */
        " 90a418881b2fcab3d9e60ee02e4d666d56cfa38f8a3b7aa3e0adba530dda9353");
    smartlist_add_linecpy(diff, area, "3c");
    smartlist_add_linecpy(diff, area, "sample");
    smartlist_add_linecpy(diff, area, ".");
    cons2 = consdiff_apply_diff(cons1, diff, &digests1);
    tt_ptr_op(NULL, OP_NE, cons2);
    tt_str_op(
        "network-status-version foo\n"
        "r name ccccccccccccccccc etc\nsample\n"
        "r name eeeeeeeeeeeeeeeee etc\nbar\n"
        "directory-signature foo bar\nbar\n", OP_EQ,
        cons2);
    spider_free(cons2);
  
    smartlist_clear(diff);
  
   done:
    teardown_capture_of_logs();
    spider_free(cons1_str);
    smartlist_free(cons1);
    smartlist_free(diff);
    memarea_drop_all(area);
  }
  
  #define CONSDIFF_LEGACY(name)                                          \
    { #name, test_consdiff_ ## name , 0, NULL, NULL }
  
  struct testcase_t consdiff_tests[] = {
    CONSDIFF_LEGACY(smartlist_slice),
    CONSDIFF_LEGACY(smartlist_slice_string_pos),
    CONSDIFF_LEGACY(lcs_lengths),
    CONSDIFF_LEGACY(trim_slices),
    CONSDIFF_LEGACY(set_changed),
    CONSDIFF_LEGACY(calc_changes),
    CONSDIFF_LEGACY(get_id_hash),
    CONSDIFF_LEGACY(is_valid_router_entry),
    CONSDIFF_LEGACY(next_router),
    CONSDIFF_LEGACY(base64cmp),
    CONSDIFF_LEGACY(gen_ed_diff),
    CONSDIFF_LEGACY(apply_ed_diff),
    CONSDIFF_LEGACY(gen_diff),
    CONSDIFF_LEGACY(apply_diff),
    END_OF_TESTCASES
  };
  
  