| | """Various utility functions.""" |
| |
|
| | from collections import namedtuple, Counter |
| | from os.path import commonprefix |
| |
|
| | __unittest = True |
| |
|
| | _MAX_LENGTH = 80 |
| | _PLACEHOLDER_LEN = 12 |
| | _MIN_BEGIN_LEN = 5 |
| | _MIN_END_LEN = 5 |
| | _MIN_COMMON_LEN = 5 |
| | _MIN_DIFF_LEN = _MAX_LENGTH - \ |
| | (_MIN_BEGIN_LEN + _PLACEHOLDER_LEN + _MIN_COMMON_LEN + |
| | _PLACEHOLDER_LEN + _MIN_END_LEN) |
| | assert _MIN_DIFF_LEN >= 0 |
| |
|
| | def _shorten(s, prefixlen, suffixlen): |
| | skip = len(s) - prefixlen - suffixlen |
| | if skip > _PLACEHOLDER_LEN: |
| | s = '%s[%d chars]%s' % (s[:prefixlen], skip, s[len(s) - suffixlen:]) |
| | return s |
| |
|
| | def _common_shorten_repr(*args): |
| | args = tuple(map(safe_repr, args)) |
| | maxlen = max(map(len, args)) |
| | if maxlen <= _MAX_LENGTH: |
| | return args |
| |
|
| | prefix = commonprefix(args) |
| | prefixlen = len(prefix) |
| |
|
| | common_len = _MAX_LENGTH - \ |
| | (maxlen - prefixlen + _MIN_BEGIN_LEN + _PLACEHOLDER_LEN) |
| | if common_len > _MIN_COMMON_LEN: |
| | assert _MIN_BEGIN_LEN + _PLACEHOLDER_LEN + _MIN_COMMON_LEN + \ |
| | (maxlen - prefixlen) < _MAX_LENGTH |
| | prefix = _shorten(prefix, _MIN_BEGIN_LEN, common_len) |
| | return tuple(prefix + s[prefixlen:] for s in args) |
| |
|
| | prefix = _shorten(prefix, _MIN_BEGIN_LEN, _MIN_COMMON_LEN) |
| | return tuple(prefix + _shorten(s[prefixlen:], _MIN_DIFF_LEN, _MIN_END_LEN) |
| | for s in args) |
| |
|
| | def safe_repr(obj, short=False): |
| | try: |
| | result = repr(obj) |
| | except Exception: |
| | result = object.__repr__(obj) |
| | if not short or len(result) < _MAX_LENGTH: |
| | return result |
| | return result[:_MAX_LENGTH] + ' [truncated]...' |
| |
|
| | def strclass(cls): |
| | return "%s.%s" % (cls.__module__, cls.__qualname__) |
| |
|
| | def sorted_list_difference(expected, actual): |
| | """Finds elements in only one or the other of two, sorted input lists. |
| | |
| | Returns a two-element tuple of lists. The first list contains those |
| | elements in the "expected" list but not in the "actual" list, and the |
| | second contains those elements in the "actual" list but not in the |
| | "expected" list. Duplicate elements in either input list are ignored. |
| | """ |
| | i = j = 0 |
| | missing = [] |
| | unexpected = [] |
| | while True: |
| | try: |
| | e = expected[i] |
| | a = actual[j] |
| | if e < a: |
| | missing.append(e) |
| | i += 1 |
| | while expected[i] == e: |
| | i += 1 |
| | elif e > a: |
| | unexpected.append(a) |
| | j += 1 |
| | while actual[j] == a: |
| | j += 1 |
| | else: |
| | i += 1 |
| | try: |
| | while expected[i] == e: |
| | i += 1 |
| | finally: |
| | j += 1 |
| | while actual[j] == a: |
| | j += 1 |
| | except IndexError: |
| | missing.extend(expected[i:]) |
| | unexpected.extend(actual[j:]) |
| | break |
| | return missing, unexpected |
| |
|
| |
|
| | def unorderable_list_difference(expected, actual): |
| | """Same behavior as sorted_list_difference but |
| | for lists of unorderable items (like dicts). |
| | |
| | As it does a linear search per item (remove) it |
| | has O(n*n) performance.""" |
| | missing = [] |
| | while expected: |
| | item = expected.pop() |
| | try: |
| | actual.remove(item) |
| | except ValueError: |
| | missing.append(item) |
| |
|
| | |
| | return missing, actual |
| |
|
| | def three_way_cmp(x, y): |
| | """Return -1 if x < y, 0 if x == y and 1 if x > y""" |
| | return (x > y) - (x < y) |
| |
|
| | _Mismatch = namedtuple('Mismatch', 'actual expected value') |
| |
|
| | def _count_diff_all_purpose(actual, expected): |
| | 'Returns list of (cnt_act, cnt_exp, elem) triples where the counts differ' |
| | |
| | s, t = list(actual), list(expected) |
| | m, n = len(s), len(t) |
| | NULL = object() |
| | result = [] |
| | for i, elem in enumerate(s): |
| | if elem is NULL: |
| | continue |
| | cnt_s = cnt_t = 0 |
| | for j in range(i, m): |
| | if s[j] == elem: |
| | cnt_s += 1 |
| | s[j] = NULL |
| | for j, other_elem in enumerate(t): |
| | if other_elem == elem: |
| | cnt_t += 1 |
| | t[j] = NULL |
| | if cnt_s != cnt_t: |
| | diff = _Mismatch(cnt_s, cnt_t, elem) |
| | result.append(diff) |
| |
|
| | for i, elem in enumerate(t): |
| | if elem is NULL: |
| | continue |
| | cnt_t = 0 |
| | for j in range(i, n): |
| | if t[j] == elem: |
| | cnt_t += 1 |
| | t[j] = NULL |
| | diff = _Mismatch(0, cnt_t, elem) |
| | result.append(diff) |
| | return result |
| |
|
| | def _count_diff_hashable(actual, expected): |
| | 'Returns list of (cnt_act, cnt_exp, elem) triples where the counts differ' |
| | |
| | s, t = Counter(actual), Counter(expected) |
| | result = [] |
| | for elem, cnt_s in s.items(): |
| | cnt_t = t.get(elem, 0) |
| | if cnt_s != cnt_t: |
| | diff = _Mismatch(cnt_s, cnt_t, elem) |
| | result.append(diff) |
| | for elem, cnt_t in t.items(): |
| | if elem not in s: |
| | diff = _Mismatch(0, cnt_t, elem) |
| | result.append(diff) |
| | return result |
| |
|