825ea9bfa1
If the compared text was in bytes and not actually valid text (i.e. could not be encoded to text/unicode using the default encoding) then the assertrepr would fail with an EncodingError. This ensures that the internal string is always valid unicode, converting any bytes safely to valid unicode. This is done using repr() which then needs post-processing to fix the encompassing quotes and un-escape newlines. This fixes issue 429.
283 lines
9.8 KiB
Python
283 lines
9.8 KiB
Python
"""Utilities for assertion debugging"""
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import py
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try:
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from collections import Sequence
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except ImportError:
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Sequence = list
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BuiltinAssertionError = py.builtin.builtins.AssertionError
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u = py.builtin._totext
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# The _reprcompare attribute on the util module is used by the new assertion
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# interpretation code and assertion rewriter to detect this plugin was
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# loaded and in turn call the hooks defined here as part of the
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# DebugInterpreter.
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_reprcompare = None
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def format_explanation(explanation):
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"""This formats an explanation
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Normally all embedded newlines are escaped, however there are
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three exceptions: \n{, \n} and \n~. The first two are intended
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cover nested explanations, see function and attribute explanations
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for examples (.visit_Call(), visit_Attribute()). The last one is
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for when one explanation needs to span multiple lines, e.g. when
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displaying diffs.
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"""
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explanation = _collapse_false(explanation)
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lines = _split_explanation(explanation)
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result = _format_lines(lines)
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return u('\n').join(result)
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def _collapse_false(explanation):
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"""Collapse expansions of False
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So this strips out any "assert False\n{where False = ...\n}"
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blocks.
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"""
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where = 0
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while True:
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start = where = explanation.find("False\n{False = ", where)
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if where == -1:
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break
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level = 0
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for i, c in enumerate(explanation[start:]):
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if c == "{":
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level += 1
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elif c == "}":
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level -= 1
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if not level:
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break
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else:
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raise AssertionError("unbalanced braces: %r" % (explanation,))
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end = start + i
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where = end
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if explanation[end - 1] == '\n':
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explanation = (explanation[:start] + explanation[start+15:end-1] +
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explanation[end+1:])
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where -= 17
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return explanation
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def _split_explanation(explanation):
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"""Return a list of individual lines in the explanation
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This will return a list of lines split on '\n{', '\n}' and '\n~'.
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Any other newlines will be escaped and appear in the line as the
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literal '\n' characters.
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"""
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raw_lines = (explanation or u('')).split('\n')
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lines = [raw_lines[0]]
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for l in raw_lines[1:]:
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if l.startswith('{') or l.startswith('}') or l.startswith('~'):
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lines.append(l)
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else:
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lines[-1] += '\\n' + l
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return lines
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def _format_lines(lines):
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"""Format the individual lines
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This will replace the '{', '}' and '~' characters of our mini
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formatting language with the proper 'where ...', 'and ...' and ' +
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...' text, taking care of indentation along the way.
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Return a list of formatted lines.
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"""
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result = lines[:1]
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stack = [0]
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stackcnt = [0]
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for line in lines[1:]:
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if line.startswith('{'):
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if stackcnt[-1]:
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s = u('and ')
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else:
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s = u('where ')
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stack.append(len(result))
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stackcnt[-1] += 1
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stackcnt.append(0)
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result.append(u(' +') + u(' ')*(len(stack)-1) + s + line[1:])
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elif line.startswith('}'):
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assert line.startswith('}')
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stack.pop()
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stackcnt.pop()
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result[stack[-1]] += line[1:]
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else:
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assert line.startswith('~')
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result.append(u(' ')*len(stack) + line[1:])
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assert len(stack) == 1
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return result
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# Provide basestring in python3
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try:
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basestring = basestring
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except NameError:
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basestring = str
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def assertrepr_compare(config, op, left, right):
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"""Return specialised explanations for some operators/operands"""
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width = 80 - 15 - len(op) - 2 # 15 chars indentation, 1 space around op
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left_repr = py.io.saferepr(left, maxsize=int(width/2))
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right_repr = py.io.saferepr(right, maxsize=width-len(left_repr))
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summary = u('%s %s %s') % (left_repr, op, right_repr)
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issequence = lambda x: (isinstance(x, (list, tuple, Sequence))
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and not isinstance(x, basestring))
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istext = lambda x: isinstance(x, basestring)
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isdict = lambda x: isinstance(x, dict)
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isset = lambda x: isinstance(x, (set, frozenset))
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verbose = config.getoption('verbose')
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explanation = None
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try:
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if op == '==':
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if istext(left) and istext(right):
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explanation = _diff_text(left, right, verbose)
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elif issequence(left) and issequence(right):
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explanation = _compare_eq_sequence(left, right, verbose)
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elif isset(left) and isset(right):
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explanation = _compare_eq_set(left, right, verbose)
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elif isdict(left) and isdict(right):
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explanation = _compare_eq_dict(left, right, verbose)
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elif op == 'not in':
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if istext(left) and istext(right):
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explanation = _notin_text(left, right, verbose)
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except Exception:
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excinfo = py.code.ExceptionInfo()
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explanation = [
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u('(pytest_assertion plugin: representation of details failed. '
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'Probably an object has a faulty __repr__.)'),
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u(excinfo)]
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if not explanation:
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return None
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return [summary] + explanation
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def _diff_text(left, right, verbose=False):
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"""Return the explanation for the diff between text or bytes
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Unless --verbose is used this will skip leading and trailing
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characters which are identical to keep the diff minimal.
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If the input are bytes they will be safely converted to text.
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"""
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explanation = []
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if isinstance(left, py.builtin.bytes):
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left = u(repr(left)[1:-1]).replace(r'\n', '\n')
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if isinstance(right, py.builtin.bytes):
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right = u(repr(right)[1:-1]).replace(r'\n', '\n')
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if not verbose:
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i = 0 # just in case left or right has zero length
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for i in range(min(len(left), len(right))):
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if left[i] != right[i]:
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break
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if i > 42:
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i -= 10 # Provide some context
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explanation = [u('Skipping %s identical leading '
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'characters in diff, use -v to show') % i]
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left = left[i:]
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right = right[i:]
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if len(left) == len(right):
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for i in range(len(left)):
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if left[-i] != right[-i]:
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break
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if i > 42:
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i -= 10 # Provide some context
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explanation += [u('Skipping %s identical trailing '
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'characters in diff, use -v to show') % i]
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left = left[:-i]
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right = right[:-i]
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explanation += [line.strip('\n')
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for line in py.std.difflib.ndiff(left.splitlines(),
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right.splitlines())]
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return explanation
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def _compare_eq_sequence(left, right, verbose=False):
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explanation = []
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for i in range(min(len(left), len(right))):
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if left[i] != right[i]:
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explanation += [u('At index %s diff: %r != %r')
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% (i, left[i], right[i])]
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break
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if len(left) > len(right):
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explanation += [u('Left contains more items, first extra item: %s')
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% py.io.saferepr(left[len(right)],)]
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elif len(left) < len(right):
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explanation += [
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u('Right contains more items, first extra item: %s') %
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py.io.saferepr(right[len(left)],)]
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return explanation # + _diff_text(py.std.pprint.pformat(left),
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# py.std.pprint.pformat(right))
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def _compare_eq_set(left, right, verbose=False):
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explanation = []
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diff_left = left - right
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diff_right = right - left
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if diff_left:
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explanation.append(u('Extra items in the left set:'))
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for item in diff_left:
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explanation.append(py.io.saferepr(item))
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if diff_right:
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explanation.append(u('Extra items in the right set:'))
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for item in diff_right:
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explanation.append(py.io.saferepr(item))
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return explanation
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def _compare_eq_dict(left, right, verbose=False):
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explanation = []
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common = set(left).intersection(set(right))
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same = dict((k, left[k]) for k in common if left[k] == right[k])
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if same and not verbose:
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explanation += [u('Omitting %s identical items, use -v to show') %
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len(same)]
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elif same:
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explanation += [u('Common items:')]
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explanation += py.std.pprint.pformat(same).splitlines()
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diff = set(k for k in common if left[k] != right[k])
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if diff:
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explanation += [u('Differing items:')]
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for k in diff:
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explanation += [py.io.saferepr({k: left[k]}) + ' != ' +
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py.io.saferepr({k: right[k]})]
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extra_left = set(left) - set(right)
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if extra_left:
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explanation.append(u('Left contains more items:'))
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explanation.extend(py.std.pprint.pformat(
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dict((k, left[k]) for k in extra_left)).splitlines())
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extra_right = set(right) - set(left)
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if extra_right:
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explanation.append(u('Right contains more items:'))
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explanation.extend(py.std.pprint.pformat(
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dict((k, right[k]) for k in extra_right)).splitlines())
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return explanation
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def _notin_text(term, text, verbose=False):
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index = text.find(term)
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head = text[:index]
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tail = text[index+len(term):]
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correct_text = head + tail
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diff = _diff_text(correct_text, text, verbose)
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newdiff = [u('%s is contained here:') % py.io.saferepr(term, maxsize=42)]
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for line in diff:
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if line.startswith(u('Skipping')):
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continue
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if line.startswith(u('- ')):
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continue
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if line.startswith(u('+ ')):
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newdiff.append(u(' ') + line[2:])
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else:
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newdiff.append(line)
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return newdiff
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