""" testfixtures.comparison ----------------------- """ from decimal import Decimal from difflib import unified_diff from functools import partial from pprint import pformat from re import compile, MULTILINE from types import GeneratorType from testfixtures import not_there from testfixtures.compat import ClassType, Iterable, Unicode, basestring, PY3 from testfixtures.resolve import resolve from testfixtures.utils import indent from testfixtures.mock import parent_name, mock_call, unittest_mock_call def compare_simple(x, y, context): """ Returns a very simple textual difference between the two supplied objects. """ if x != y: repr_x = repr(x) repr_y = repr(y) if repr_x == repr_y: if type(x) is not type(y): return compare_with_type(x, y, context) x_attrs = _extract_attrs(x) y_attrs = _extract_attrs(y) diff = _compare_mapping(x_attrs, y_attrs, context, x, 'attributes ', '.%s') if not diff: return 'Both %s and %s appear as %r, but are not equal!' % ( context.x_label or 'x', context.y_label or 'y', repr_x ) return diff return context.label('x', repr_x) + ' != ' + context.label('y', repr_y) def _extract_attrs(obj, ignore=None): try: attrs = vars(obj).copy() except TypeError: attrs = None else: if isinstance(obj, BaseException): attrs['args'] = obj.args has_slots = getattr(obj, '__slots__', not_there) is not not_there if has_slots: slots = set() for cls in type(obj).__mro__: slots.update(getattr(cls, '__slots__', ())) if slots and attrs is None: attrs = {} for n in slots: value = getattr(obj, n, not_there) if value is not not_there: attrs[n] = value if attrs is None: return None if ignore is not None: for attr in ignore: attrs.pop(attr, None) return attrs def _attrs_to_ignore(context, ignore_attributes, obj): ignore = context.get_option('ignore_attributes', ()) if isinstance(ignore, dict): ignore = ignore.get(type(obj), ()) ignore = set(ignore) ignore.update(ignore_attributes) return ignore def compare_object(x, y, context, ignore_attributes=()): """ Compare the two supplied objects based on their type and attributes. :param ignore_attributes: Either a sequence of strings containing attribute names to be ignored when comparing or a mapping of type to sequence of strings containing attribute names to be ignored when comparing that type. This may be specified as either a parameter to this function or in the ``context``. If specified in both, they will both apply with precedence given to whatever is specified is specified as a parameter. If specified as a parameter to this fucntion, it may only be a list of strings. """ if type(x) is not type(y) or isinstance(x, (ClassType, type)): return compare_simple(x, y, context) x_attrs = _extract_attrs(x, _attrs_to_ignore(context, ignore_attributes, x)) y_attrs = _extract_attrs(y, _attrs_to_ignore(context, ignore_attributes, y)) if x_attrs is None or y_attrs is None or not (x_attrs and y_attrs): return compare_simple(x, y, context) if x_attrs != y_attrs: return _compare_mapping(x_attrs, y_attrs, context, x, 'attributes ', '.%s') def compare_exception(x, y, context): """ Compare the two supplied exceptions based on their message, type and attributes. """ if x.args != y.args: return compare_simple(x, y, context) return compare_object(x, y, context) def compare_with_type(x, y, context): """ Return a textual description of the difference between two objects including information about their types. """ source = locals() to_render = {} for name in 'x', 'y': obj = source[name] to_render[name] = context.label( name, '{0} ({1!r})'.format(_short_repr(obj), type(obj)) ) return '{x} != {y}'.format(**to_render) def compare_sequence(x, y, context): """ Returns a textual description of the differences between the two supplied sequences. """ l_x = len(x) l_y = len(y) i = 0 while i < l_x and i < l_y: if context.different(x[i], y[i], '[%i]' % i): break i += 1 if l_x == l_y and i == l_x: return return ('sequence not as expected:\n\n' 'same:\n%s\n\n' '%s:\n%s\n\n' '%s:\n%s') % (pformat(x[:i]), context.x_label or 'first', pformat(x[i:]), context.y_label or 'second', pformat(y[i:]), ) def compare_generator(x, y, context): """ Returns a textual description of the differences between the two supplied generators. This is done by first unwinding each of the generators supplied into tuples and then passing those tuples to :func:`compare_sequence`. """ x = tuple(x) y = tuple(y) if not context.ignore_eq and x == y: return return compare_sequence(x, y, context) def compare_tuple(x, y, context): """ Returns a textual difference between two tuples or :func:`collections.namedtuple` instances. The presence of a ``_fields`` attribute on a tuple is used to decide whether or not it is a :func:`~collections.namedtuple`. """ x_fields = getattr(x, '_fields', None) y_fields = getattr(y, '_fields', None) if x_fields and y_fields: if x_fields == y_fields: return _compare_mapping(dict(zip(x_fields, x)), dict(zip(y_fields, y)), context, x) else: return compare_with_type(x, y, context) return compare_sequence(x, y, context) def compare_dict(x, y, context): """ Returns a textual description of the differences between the two supplied dictionaries. """ return _compare_mapping(x, y, context, x) def sorted_by_repr(sequence): return sorted(sequence, key=lambda o: repr(o)) def _compare_mapping(x, y, context, obj_for_class, prefix='', breadcrumb='[%r]', check_y_not_x=True): x_keys = set(x.keys()) y_keys = set(y.keys()) x_not_y = x_keys - y_keys y_not_x = y_keys - x_keys same = [] diffs = [] for key in sorted_by_repr(x_keys.intersection(y_keys)): if context.different(x[key], y[key], breadcrumb % (key, )): diffs.append('%r: %s != %s' % ( key, context.label('x', pformat(x[key])), context.label('y', pformat(y[key])), )) else: same.append(key) if not (x_not_y or (check_y_not_x and y_not_x) or diffs): return if obj_for_class is not_there: lines = [] else: lines = ['%s not as expected:' % obj_for_class.__class__.__name__] if same: try: same = sorted(same) except TypeError: pass lines.extend(('', '%ssame:' % prefix, repr(same))) x_label = context.x_label or 'first' y_label = context.y_label or 'second' if x_not_y: lines.extend(('', '%sin %s but not %s:' % (prefix, x_label, y_label))) for key in sorted_by_repr(x_not_y): lines.append('%r: %s' % ( key, pformat(x[key]) )) if y_not_x: lines.extend(('', '%sin %s but not %s:' % (prefix, y_label, x_label))) for key in sorted_by_repr(y_not_x): lines.append('%r: %s' % ( key, pformat(y[key]) )) if diffs: lines.extend(('', '%sdiffer:' % (prefix or 'values '))) lines.extend(diffs) return '\n'.join(lines) def compare_set(x, y, context): """ Returns a textual description of the differences between the two supplied sets. """ x_not_y = x - y y_not_x = y - x if not (y_not_x or x_not_y): return lines = ['%s not as expected:' % x.__class__.__name__, ''] x_label = context.x_label or 'first' y_label = context.y_label or 'second' if x_not_y: lines.extend(( 'in %s but not %s:' % (x_label, y_label), pformat(sorted_by_repr(x_not_y)), '', )) if y_not_x: lines.extend(( 'in %s but not %s:' % (y_label, x_label), pformat(sorted_by_repr(y_not_x)), '', )) return '\n'.join(lines)+'\n' trailing_whitespace_re = compile('\s+$', MULTILINE) def strip_blank_lines(text): result = [] for line in text.split('\n'): if line and not line.isspace(): result.append(line) return '\n'.join(result) def split_repr(text): parts = text.split('\n') for i, part in enumerate(parts[:-1]): parts[i] = repr(part + '\n') parts[-1] = repr(parts[-1]) return '\n'.join(parts) def compare_text(x, y, context): """ Returns an informative string describing the differences between the two supplied strings. The way in which this comparison is performed can be controlled using the following parameters: :param blanklines: If `False`, then when comparing multi-line strings, any blank lines in either argument will be ignored. :param trailing_whitespace: If `False`, then when comparing multi-line strings, trailing whilespace on lines will be ignored. :param show_whitespace: If `True`, then whitespace characters in multi-line strings will be replaced with their representations. """ blanklines = context.get_option('blanklines', True) trailing_whitespace = context.get_option('trailing_whitespace', True) show_whitespace = context.get_option('show_whitespace', False) if not trailing_whitespace: x = trailing_whitespace_re.sub('', x) y = trailing_whitespace_re.sub('', y) if not blanklines: x = strip_blank_lines(x) y = strip_blank_lines(y) if x == y: return labelled_x = context.label('x', repr(x)) labelled_y = context.label('y', repr(y)) if len(x) > 10 or len(y) > 10: if '\n' in x or '\n' in y: if show_whitespace: x = split_repr(x) y = split_repr(y) message = '\n' + diff(x, y, context.x_label, context.y_label) else: message = '\n%s\n!=\n%s' % (labelled_x, labelled_y) else: message = labelled_x+' != '+labelled_y return message def compare_bytes(x, y, context): if x == y: return labelled_x = context.label('x', repr(x)) labelled_y = context.label('y', repr(y)) return '\n%s\n!=\n%s' % (labelled_x, labelled_y) def compare_call(x, y, context): if x == y: return def extract(call): try: name, args, kwargs = call except ValueError: name = None args, kwargs = call return name, args, kwargs x_name, x_args, x_kw = extract(x) y_name, y_args, y_kw = extract(y) if x_name == y_name and x_args == y_args and x_kw == y_kw: return compare_call(getattr(x, parent_name), getattr(y, parent_name), context) if repr(x) != repr(y): return compare_text(repr(x), repr(y), context) different = ( context.different(x_name, y_name, ' function name') or context.different(x_args, y_args, ' args') or context.different(x_kw, y_kw, ' kw') ) if not different: return return 'mock.call not as expected:' def compare_partial(x, y, context): x_attrs = dict(func=x.func, args=x.args, keywords=x.keywords) y_attrs = dict(func=y.func, args=y.args, keywords=y.keywords) if x_attrs != y_attrs: return _compare_mapping(x_attrs, y_attrs, context, x, 'attributes ', '.%s') def _short_repr(obj): repr_ = repr(obj) if len(repr_) > 30: repr_ = repr_[:30] + '...' return repr_ _registry = { dict: compare_dict, set: compare_set, list: compare_sequence, tuple: compare_tuple, str: compare_text, Unicode: compare_text, int: compare_simple, float: compare_simple, Decimal: compare_simple, GeneratorType: compare_generator, mock_call.__class__: compare_call, unittest_mock_call.__class__: compare_call, BaseException: compare_exception, partial: compare_partial, } if PY3: _registry[bytes] = compare_bytes def register(type, comparer): """ Register the supplied comparer for the specified type. This registration is global and will be in effect from the point this function is called until the end of the current process. """ _registry[type] = comparer def _mro(obj): class_ = getattr(obj, '__class__', None) if class_ is None: # must be an old-style class object in Python 2! return (obj, ) mro = getattr(class_, '__mro__', None) if mro is None: # instance of old-style class in Python 2! return (class_, ) return mro def _shared_mro(x, y): y_mro = set(_mro(y)) for class_ in _mro(x): if class_ in y_mro: yield class_ _unsafe_iterables = basestring, dict class CompareContext(object): x_label = y_label = None def __init__(self, options): self.registries = [] comparers = options.pop('comparers', None) if comparers: self.registries.append(comparers) self.registries.append(_registry) self.recursive = options.pop('recursive', True) self.strict = options.pop('strict', False) self.ignore_eq = options.pop('ignore_eq', False) if 'expected' in options or 'actual' in options: self.x_label = 'expected' self.y_label = 'actual' self.x_label = options.pop('x_label', self.x_label) self.y_label = options.pop('y_label', self.y_label) self.options = options self.message = '' self.breadcrumbs = [] self._seen = set() def extract_args(self, args): possible = [] expected = self.options.pop('expected', not_there) if expected is not not_there: possible.append(expected) possible.extend(args) actual = self.options.pop('actual', not_there) if actual is not not_there: possible.append(actual) x = self.options.pop('x', not_there) if x is not not_there: possible.append(x) y = self.options.pop('y', not_there) if y is not not_there: possible.append(y) if len(possible) != 2: message = 'Exactly two objects needed, you supplied:' if possible: message += ' {}'.format(possible) if self.options: message += ' {}'.format(self.options) raise TypeError(message) return possible def get_option(self, name, default=None): return self.options.get(name, default) def label(self, side, value): r = str(value) label = getattr(self, side+'_label') if label: r += ' ('+label+')' return r def _lookup(self, x, y): if self.strict and type(x) is not type(y): return compare_with_type for class_ in _shared_mro(x, y): for registry in self.registries: comparer = registry.get(class_) if comparer: return comparer # fallback for iterables if ((isinstance(x, Iterable) and isinstance(y, Iterable)) and not (isinstance(x, _unsafe_iterables) or isinstance(y, _unsafe_iterables))): return compare_generator # special handling for Comparisons: if isinstance(x, Comparison) or isinstance(y, Comparison): return compare_simple return compare_object def _separator(self): return '\n\nWhile comparing %s: ' % ''.join(self.breadcrumbs[1:]) def seen(self, x, y): # don't get confused by string interning: if isinstance(x, basestring) and isinstance(y, basestring): return False key = id(x), id(y) if key in self._seen: return True self._seen.add(key) def different(self, x, y, breadcrumb): if self.seen(x, y): # a self-referential hierarchy; so lets say this one is # equal and hope the first time we saw it covers things... return False recursed = bool(self.breadcrumbs) self.breadcrumbs.append(breadcrumb) existing_message = self.message self.message = '' current_message = '' try: if not (self.strict or self.ignore_eq) and x == y: return False comparer = self._lookup(x, y) result = comparer(x, y, self) specific_comparer = comparer is not compare_simple if self.strict: if x == y and not specific_comparer: return False if result: if specific_comparer and recursed: current_message = self._separator() if specific_comparer or not recursed: current_message += result if self.recursive: current_message += self.message return result finally: self.message = existing_message + current_message self.breadcrumbs.pop() def compare(*args, **kw): """ Compare two objects, raising an :class:`AssertionError` if they are not the same. The :class:`AssertionError` raised will attempt to provide descriptions of the differences found. The two objects to compare can be passed either positionally or using explicit keyword arguments named ``x`` and ``y``, or ``expected`` and ``actual``. Any other keyword parameters supplied will be passed to the functions that end up doing the comparison. See the :mod:`API documentation below ` for details of these. :param prefix: If provided, in the event of an :class:`AssertionError` being raised, the prefix supplied will be prepended to the message in the :class:`AssertionError`. :param suffix: If provided, in the event of an :class:`AssertionError` being raised, the suffix supplied will be appended to the message in the :class:`AssertionError`. :param x_label: If provided, in the event of an :class:`AssertionError` being raised, the object passed as the first positional argument, or ``x`` keyword argument, will be labelled with this string in the message in the :class:`AssertionError`. :param x_label: If provided, in the event of an :class:`AssertionError` being raised, the object passed as the second positional argument, or ``y`` keyword argument, will be labelled with this string in the message in the :class:`AssertionError`. :param raises: If ``False``, the message that would be raised in the :class:`AssertionError` will be returned instead of the exception being raised. :param recursive: If ``True``, when a difference is found in a nested data structure, attempt to highlight the location of the difference. :param strict: If ``True``, objects will only compare equal if they are of the same type as well as being equal. :param ignore_eq: If ``True``, object equality, which relies on ``__eq__`` being correctly implemented, will not be used. Instead, comparers will be looked up and used and, if no suitable comparer is found, objects will be considered equal if their hash is equal. :param comparers: If supplied, should be a dictionary mapping types to comparer functions for those types. These will be added to the comparer registry for the duration of this call. """ __tracebackhide__ = True prefix = kw.pop('prefix', None) suffix = kw.pop('suffix', None) raises = kw.pop('raises', True) context = CompareContext(kw) x, y = context.extract_args(args) if not context.different(x, y, not_there): return message = context.message if prefix: message = prefix + ': ' + message if suffix: message += '\n' + suffix if raises: raise AssertionError(message) return message class Comparison(object): """ These are used when you need to compare objects that do not natively support comparison. :param object_or_type: The object or class from which to create the :class:`Comparison`. :param attribute_dict: An optional dictionary containing attibutes to place on the :class:`Comparison`. :param strict: If true, any expected attributes not present or extra attributes not expected on the object involved in the comparison will cause the comparison to fail. :param attributes: Any other keyword parameters passed will placed as attributes on the :class:`Comparison`. """ failed = None def __init__(self, object_or_type, attribute_dict=None, strict=True, **attributes): if attributes: if attribute_dict is None: attribute_dict = attributes else: attribute_dict.update(attributes) if isinstance(object_or_type, basestring): container, method, name, c = resolve(object_or_type) if c is not_there: raise AttributeError( '%r could not be resolved' % object_or_type ) elif isinstance(object_or_type, (ClassType, type)): c = object_or_type else: c = object_or_type.__class__ if attribute_dict is None: attribute_dict = _extract_attrs(object_or_type) self.c = c self.v = attribute_dict self.strict = strict def __eq__(self, other): if self.c is not other.__class__: self.failed = 'wrong type' return False if self.v is None: return True remaining_keys = set(self.v.keys()) if self.strict: v = _extract_attrs(other) remaining_keys -= set(v.keys()) else: v = {} while remaining_keys: k = remaining_keys.pop() try: v[k] = getattr(other, k) except AttributeError: pass kw = {'x_label': 'Comparison', 'y_label': 'actual'} context = CompareContext(kw) self.failed = _compare_mapping(self.v, v, context, obj_for_class=not_there, prefix='attributes ', breadcrumb='.%s', check_y_not_x=self.strict) return not self.failed def __ne__(self, other): return not(self == other) def __repr__(self): name = getattr(self.c, '__module__', '') if name: name += '.' name += getattr(self.c, '__name__', '') if not name: name = repr(self.c) text = '' if self.failed: text = self.failed elif self.v: lines = [] for k, v in sorted(self.v.items()): rv = repr(v) if '\n' in rv: rv = indent(rv) lines.append('%s: %s' % (k, rv)) text = '\n'.join(lines) if len(lines) > 1: text = '\n'+text r = '' % (self.failed and '(failed)' or '', name) if '\n' in text: r = '\n'+r+text+'\n' else: r += text if text: r += '' return r class StringComparison: """ An object that can be used in comparisons of expected and actual strings where the string expected matches a pattern rather than a specific concrete string. :param regex_source: A string containing the source for a regular expression that will be used whenever this :class:`StringComparison` is compared with any :class:`basestring` instance. """ def __init__(self, regex_source): self.re = compile(regex_source) def __eq__(self, other): if not isinstance(other, basestring): return if self.re.match(other): return True return False def __ne__(self, other): return not self == other def __repr__(self): return '' % self.re.pattern def __lt__(self, other): return self.re.pattern < other def __gt__(self, other): return self.re.pattern > other class RoundComparison: """ An object that can be used in comparisons of expected and actual numerics to a specified precision. :param value: numeric to be compared. :param precision: Number of decimal places to round to in order to perform the comparison. """ def __init__(self, value, precision): self.rounded = round(value, precision) self.precision = precision def __eq__(self, other): other_rounded = round(other, self.precision) if type(self.rounded) is not type(other_rounded): raise TypeError('Cannot compare %r with %r' % (self, type(other))) return self.rounded == other_rounded def __ne__(self, other): return not self == other def __repr__(self): return '' % (self.rounded, self.precision) def diff(x, y, x_label='', y_label=''): """ A shorthand function that uses :mod:`difflib` to return a string representing the differences between the two string arguments. Most useful when comparing multi-line strings. """ return '\n'.join( unified_diff( x.split('\n'), y.split('\n'), x_label or 'first', y_label or 'second', lineterm='') ) class RangeComparison: """ An object that can be used in comparisons of orderable types to check that a value specified within the given range. :param lower_bound: the inclusive lower bound for the acceptable range. :param upper_bound: the inclusive upper bound for the acceptable range. """ def __init__(self, lower_bound, upper_bound): self.lower_bound = lower_bound self.upper_bound = upper_bound def __eq__(self, other): return self.lower_bound <= other <= self.upper_bound def __ne__(self, other): return not self == other def __repr__(self): return '' % (self.lower_bound, self.upper_bound)