Johnny Chen | 7325883 | 2010-08-05 23:42:46 +0000 | [diff] [blame] | 1 | """Various utility functions.""" |
| 2 | |
| 3 | __unittest = True |
| 4 | |
| 5 | |
| 6 | _MAX_LENGTH = 80 |
| 7 | def safe_repr(obj, short=False): |
| 8 | try: |
| 9 | result = repr(obj) |
| 10 | except Exception: |
| 11 | result = object.__repr__(obj) |
| 12 | if not short or len(result) < _MAX_LENGTH: |
| 13 | return result |
| 14 | return result[:_MAX_LENGTH] + ' [truncated]...' |
| 15 | |
| 16 | def safe_str(obj): |
| 17 | try: |
| 18 | return str(obj) |
| 19 | except Exception: |
| 20 | return object.__str__(obj) |
| 21 | |
| 22 | def strclass(cls): |
| 23 | return "%s.%s" % (cls.__module__, cls.__name__) |
| 24 | |
| 25 | def sorted_list_difference(expected, actual): |
| 26 | """Finds elements in only one or the other of two, sorted input lists. |
| 27 | |
| 28 | Returns a two-element tuple of lists. The first list contains those |
| 29 | elements in the "expected" list but not in the "actual" list, and the |
| 30 | second contains those elements in the "actual" list but not in the |
| 31 | "expected" list. Duplicate elements in either input list are ignored. |
| 32 | """ |
| 33 | i = j = 0 |
| 34 | missing = [] |
| 35 | unexpected = [] |
| 36 | while True: |
| 37 | try: |
| 38 | e = expected[i] |
| 39 | a = actual[j] |
| 40 | if e < a: |
| 41 | missing.append(e) |
| 42 | i += 1 |
| 43 | while expected[i] == e: |
| 44 | i += 1 |
| 45 | elif e > a: |
| 46 | unexpected.append(a) |
| 47 | j += 1 |
| 48 | while actual[j] == a: |
| 49 | j += 1 |
| 50 | else: |
| 51 | i += 1 |
| 52 | try: |
| 53 | while expected[i] == e: |
| 54 | i += 1 |
| 55 | finally: |
| 56 | j += 1 |
| 57 | while actual[j] == a: |
| 58 | j += 1 |
| 59 | except IndexError: |
| 60 | missing.extend(expected[i:]) |
| 61 | unexpected.extend(actual[j:]) |
| 62 | break |
| 63 | return missing, unexpected |
| 64 | |
| 65 | def unorderable_list_difference(expected, actual, ignore_duplicate=False): |
| 66 | """Same behavior as sorted_list_difference but |
| 67 | for lists of unorderable items (like dicts). |
| 68 | |
| 69 | As it does a linear search per item (remove) it |
| 70 | has O(n*n) performance. |
| 71 | """ |
| 72 | missing = [] |
| 73 | unexpected = [] |
| 74 | while expected: |
| 75 | item = expected.pop() |
| 76 | try: |
| 77 | actual.remove(item) |
| 78 | except ValueError: |
| 79 | missing.append(item) |
| 80 | if ignore_duplicate: |
| 81 | for lst in expected, actual: |
| 82 | try: |
| 83 | while True: |
| 84 | lst.remove(item) |
| 85 | except ValueError: |
| 86 | pass |
| 87 | if ignore_duplicate: |
| 88 | while actual: |
| 89 | item = actual.pop() |
| 90 | unexpected.append(item) |
| 91 | try: |
| 92 | while True: |
| 93 | actual.remove(item) |
| 94 | except ValueError: |
| 95 | pass |
| 96 | return missing, unexpected |
| 97 | |
| 98 | # anything left in actual is unexpected |
| 99 | return missing, actual |