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140 lines
4.1 KiB
Python
140 lines
4.1 KiB
Python
"""Various utility functions."""
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from collections import namedtuple, OrderedDict
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__unittest = True
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_MAX_LENGTH = 80
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def safe_repr(obj, short=False):
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try:
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result = repr(obj)
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except Exception:
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result = object.__repr__(obj)
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if not short or len(result) < _MAX_LENGTH:
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return result
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return result[:_MAX_LENGTH] + ' [truncated]...'
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def strclass(cls):
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return "%s.%s" % (cls.__module__, cls.__name__)
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def sorted_list_difference(expected, actual):
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"""Finds elements in only one or the other of two, sorted input lists.
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Returns a two-element tuple of lists. The first list contains those
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elements in the "expected" list but not in the "actual" list, and the
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second contains those elements in the "actual" list but not in the
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"expected" list. Duplicate elements in either input list are ignored.
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"""
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i = j = 0
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missing = []
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unexpected = []
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while True:
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try:
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e = expected[i]
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a = actual[j]
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if e < a:
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missing.append(e)
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i += 1
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while expected[i] == e:
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i += 1
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elif e > a:
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unexpected.append(a)
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j += 1
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while actual[j] == a:
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j += 1
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else:
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i += 1
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try:
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while expected[i] == e:
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i += 1
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finally:
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j += 1
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while actual[j] == a:
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j += 1
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except IndexError:
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missing.extend(expected[i:])
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unexpected.extend(actual[j:])
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break
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return missing, unexpected
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def unorderable_list_difference(expected, actual):
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"""Same behavior as sorted_list_difference but
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for lists of unorderable items (like dicts).
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As it does a linear search per item (remove) it
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has O(n*n) performance."""
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missing = []
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while expected:
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item = expected.pop()
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try:
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actual.remove(item)
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except ValueError:
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missing.append(item)
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# anything left in actual is unexpected
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return missing, actual
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def three_way_cmp(x, y):
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"""Return -1 if x < y, 0 if x == y and 1 if x > y"""
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return (x > y) - (x < y)
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_Mismatch = namedtuple('Mismatch', 'actual expected value')
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def _count_diff_all_purpose(actual, expected):
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'Returns list of (cnt_act, cnt_exp, elem) triples where the counts differ'
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# elements need not be hashable
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s, t = list(actual), list(expected)
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m, n = len(s), len(t)
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NULL = object()
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result = []
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for i, elem in enumerate(s):
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if elem is NULL:
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continue
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cnt_s = cnt_t = 0
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for j in range(i, m):
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if s[j] == elem:
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cnt_s += 1
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s[j] = NULL
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for j, other_elem in enumerate(t):
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if other_elem == elem:
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cnt_t += 1
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t[j] = NULL
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if cnt_s != cnt_t:
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diff = _Mismatch(cnt_s, cnt_t, elem)
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result.append(diff)
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for i, elem in enumerate(t):
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if elem is NULL:
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continue
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cnt_t = 0
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for j in range(i, n):
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if t[j] == elem:
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cnt_t += 1
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t[j] = NULL
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diff = _Mismatch(0, cnt_t, elem)
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result.append(diff)
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return result
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def _ordered_count(iterable):
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'Return dict of element counts, in the order they were first seen'
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c = OrderedDict()
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for elem in iterable:
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c[elem] = c.get(elem, 0) + 1
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return c
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def _count_diff_hashable(actual, expected):
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'Returns list of (cnt_act, cnt_exp, elem) triples where the counts differ'
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# elements must be hashable
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s, t = _ordered_count(actual), _ordered_count(expected)
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result = []
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for elem, cnt_s in s.items():
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cnt_t = t.get(elem, 0)
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if cnt_s != cnt_t:
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diff = _Mismatch(cnt_s, cnt_t, elem)
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result.append(diff)
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for elem, cnt_t in t.items():
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if elem not in s:
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diff = _Mismatch(0, cnt_t, elem)
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result.append(diff)
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return result
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