242 lines
		
	
	
		
			8.5 KiB
		
	
	
	
		
			Python
		
	
	
	
			
		
		
	
	
			242 lines
		
	
	
		
			8.5 KiB
		
	
	
	
		
			Python
		
	
	
	
"""Utilities for assertion debugging"""
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import py
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BuiltinAssertionError = py.builtin.builtins.AssertionError
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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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    # simplify 'assert False where False = ...'
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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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    raw_lines = (explanation or '').split('\n')
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    # escape newlines not followed by {, } and ~
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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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    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 = 'and   '
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            else:
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                s = '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(' +' + '  '*(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('  '*len(stack) + line[1:])
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    assert len(stack) == 1
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    return '\n'.join(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 = '%s %s %s' % (left_repr, op, right_repr)
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    issequence = lambda x: isinstance(x, (list, tuple))
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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 py.builtin._sysex:
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        raise
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    except:
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        excinfo = py.code.ExceptionInfo()
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        explanation = [
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            '(pytest_assertion plugin: representation of details failed.  '
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            'Probably an object has a faulty __repr__.)', str(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
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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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    """
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    explanation = []
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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 = ['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 += ['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 += ['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 += [
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            '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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            '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('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('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 += ['Hiding %s identical items, use -v to show' %
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                        len(same)]
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    elif same:
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        explanation += ['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 += ['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('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('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 = ['%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('Skipping'):
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            continue
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        if line.startswith('- '):
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            continue
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        if line.startswith('+ '):
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            newdiff.append('  ' + line[2:])
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        else:
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            newdiff.append(line)
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    return newdiff
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