Package lxml :: Module doctestcompare |
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# Source Code for Module lxml.doctestcompare

      1  """
      2  lxml-based doctest output comparison.
      3
      4  Note: normally, you should just import the `lxml.usedoctest` and
      5  `lxml.html.usedoctest` modules from within a doctest, instead of this
      6  one::
      7
      8      >>> import lxml.usedoctest # for XML output
      9
     10      >>> import lxml.html.usedoctest # for HTML output
     11
     12  To use this module directly, you must call ``lxmldoctest.install()``,
     13  which will cause doctest to use this in all subsequent calls.
     14
     15  This changes the way output is checked and comparisons are made for
     16  XML or HTML-like content.
     17
     18  XML or HTML content is noticed because the example starts with ``<``
     19  (it's HTML if it starts with ``<html``).  You can also use the
     20  ``PARSE_HTML`` and ``PARSE_XML`` flags to force parsing.
     21
     22  Some rough wildcard-like things are allowed.  Whitespace is generally
     23  ignored (except in attributes).  In text (attributes and text in the
     24  body) you can use ``...`` as a wildcard.  In an example it also
     25  matches any trailing tags in the element, though it does not match
     26  leading tags.  You may create a tag ``<any>`` or include an ``any``
     27  attribute in the tag.  An ``any`` tag matches any tag, while the
     28  attribute matches any and all attributes.
     29
     30  When a match fails, the reformatted example and gotten text is
     31  displayed (indented), and a rough diff-like output is given.  Anything
     32  marked with ``-`` is in the output but wasn't supposed to be, and
     33  similarly ``+`` means its in the example but wasn't in the output.
     34
     35  You can disable parsing on one line with ``# doctest:+NOPARSE_MARKUP``
     36  """
     37
     38  from lxml import etree
     39  import sys
     40  import re
     41  import doctest
     42  import cgi
     43
     44  __all__ = ['PARSE_HTML', 'PARSE_XML', 'NOPARSE_MARKUP', 'LXMLOutputChecker',
     45             'LHTMLOutputChecker', 'install', 'temp_install']
     46
     47  try:
     48      _basestring = basestring
     49  except NameError:
     50      _basestring = (str, bytes)
     51
     52  _IS_PYTHON_3 = sys.version_info[0] >= 3
     53
     54  PARSE_HTML = doctest.register_optionflag('PARSE_HTML')
     55  PARSE_XML = doctest.register_optionflag('PARSE_XML')
     56  NOPARSE_MARKUP = doctest.register_optionflag('NOPARSE_MARKUP')
     57
     58  OutputChecker = doctest.OutputChecker
     59
     60 -def strip(v):
     61      if v is None:
     62          return None
     63      else:
     64          return v.strip()
     65
     66 -def norm_whitespace(v):
     67      return _norm_whitespace_re.sub(' ', v)
     68
     69  _html_parser = etree.HTMLParser(recover=False, remove_blank_text=True)
     70
     71 -def html_fromstring(html):
     72      return etree.fromstring(html, _html_parser)
     73
     74  # We use this to distinguish repr()s from elements:
     75  _repr_re = re.compile(r'^<[^>]+ (at|object) ')
     76  _norm_whitespace_re = re.compile(r'[ \t\n][ \t\n]+')
     77
     78 -class LXMLOutputChecker(OutputChecker):
     79
     80      empty_tags = (
     81          'param', 'img', 'area', 'br', 'basefont', 'input',
     82          'base', 'meta', 'link', 'col')
     83
     84 -    def get_default_parser(self):
     85          return etree.XML
     86
     87 -    def check_output(self, want, got, optionflags):
     88          alt_self = getattr(self, '_temp_override_self', None)
     89          if alt_self is not None:
     90              super_method = self._temp_call_super_check_output
     91              self = alt_self
     92          else:
     93              super_method = OutputChecker.check_output
     94          parser = self.get_parser(want, got, optionflags)
     95          if not parser:
     96              return super_method(
     97                  self, want, got, optionflags)
     98          try:
     99              want_doc = parser(want)
    100          except etree.XMLSyntaxError:
    101              return False
    102          try:
    103              got_doc = parser(got)
    104          except etree.XMLSyntaxError:
    105              return False
    106          return self.compare_docs(want_doc, got_doc)
    107
    108 -    def get_parser(self, want, got, optionflags):
    109          parser = None
    110          if NOPARSE_MARKUP & optionflags:
    111              return None
    112          if PARSE_HTML & optionflags:
    113              parser = html_fromstring
    114          elif PARSE_XML & optionflags:
    115              parser = etree.XML
    116          elif (want.strip().lower().startswith('<html')
    117                and got.strip().startswith('<html')):
    118              parser = html_fromstring
    119          elif (self._looks_like_markup(want)
    120                and self._looks_like_markup(got)):
    121              parser = self.get_default_parser()
    122          return parser
    123
    124 -    def _looks_like_markup(self, s):
    125          s = s.strip()
    126          return (s.startswith('<')
    127                  and not _repr_re.search(s))
    128
    129 -    def compare_docs(self, want, got):
    130          if not self.tag_compare(want.tag, got.tag):
    131              return False
    132          if not self.text_compare(want.text, got.text, True):
    133              return False
    134          if not self.text_compare(want.tail, got.tail, True):
    135              return False
    136          if 'any' not in want.attrib:
    137              want_keys = sorted(want.attrib.keys())
    138              got_keys = sorted(got.attrib.keys())
    139              if want_keys != got_keys:
    140                  return False
    141              for key in want_keys:
    142                  if not self.text_compare(want.attrib[key], got.attrib[key], False):
    143                      return False
    144          if want.text != '...' or len(want):
    145              want_children = list(want)
    146              got_children = list(got)
    147              while want_children or got_children:
    148                  if not want_children or not got_children:
    149                      return False
    150                  want_first = want_children.pop(0)
    151                  got_first = got_children.pop(0)
    152                  if not self.compare_docs(want_first, got_first):
    153                      return False
    154                  if not got_children and want_first.tail == '...':
    155                      break
    156          return True
    157
    158 -    def text_compare(self, want, got, strip):
    159          want = want or ''
    160          got = got or ''
    161          if strip:
    162              want = norm_whitespace(want).strip()
    163              got = norm_whitespace(got).strip()
    164          want = '^%s$' % re.escape(want)
    165          want = want.replace(r'\.\.\.', '.*')
    166          if re.search(want, got):
    167              return True
    168          else:
    169              return False
    170
    171 -    def tag_compare(self, want, got):
    172          if want == 'any':
    173              return True
    174          if (not isinstance(want, _basestring)
    175              or not isinstance(got, _basestring)):
    176              return want == got
    177          want = want or ''
    178          got = got or ''
    179          if want.startswith('{...}'):
    180              # Ellipsis on the namespace
    181              return want.split('}')[-1] == got.split('}')[-1]
    182          else:
    183              return want == got
    184
    185 -    def output_difference(self, example, got, optionflags):
    186          want = example.want
    187          parser = self.get_parser(want, got, optionflags)
    188          errors = []
    189          if parser is not None:
    190              try:
    191                  want_doc = parser(want)
    192              except etree.XMLSyntaxError:
    193                  e = sys.exc_info()[1]
    194                  errors.append('In example: %s' % e)
    195              try:
    196                  got_doc = parser(got)
    197              except etree.XMLSyntaxError:
    198                  e = sys.exc_info()[1]
    199                  errors.append('In actual output: %s' % e)
    200          if parser is None or errors:
    201              value = OutputChecker.output_difference(
    202                  self, example, got, optionflags)
    203              if errors:
    204                  errors.append(value)
    205                  return '\n'.join(errors)
    206              else:
    207                  return value
    208          html = parser is html_fromstring
    209          diff_parts = []
    210          diff_parts.append('Expected:')
    211          diff_parts.append(self.format_doc(want_doc, html, 2))
    212          diff_parts.append('Got:')
    213          diff_parts.append(self.format_doc(got_doc, html, 2))
    214          diff_parts.append('Diff:')
    215          diff_parts.append(self.collect_diff(want_doc, got_doc, html, 2))
    216          return '\n'.join(diff_parts)
    217
    218 -    def html_empty_tag(self, el, html=True):
    219          if not html:
    220              return False
    221          if el.tag not in self.empty_tags:
    222              return False
    223          if el.text or len(el):
    224              # This shouldn't happen (contents in an empty tag)
    225              return False
    226          return True
    227
    228 -    def format_doc(self, doc, html, indent, prefix=''):
    229          parts = []
    230          if not len(doc):
    231              # No children...
    232              parts.append(' '*indent)
    233              parts.append(prefix)
    234              parts.append(self.format_tag(doc))
    235              if not self.html_empty_tag(doc, html):
    236                  if strip(doc.text):
    237                      parts.append(self.format_text(doc.text))
    238                  parts.append(self.format_end_tag(doc))
    239              if strip(doc.tail):
    240                  parts.append(self.format_text(doc.tail))
    241              parts.append('\n')
    242              return ''.join(parts)
    243          parts.append(' '*indent)
    244          parts.append(prefix)
    245          parts.append(self.format_tag(doc))
    246          if not self.html_empty_tag(doc, html):
    247              parts.append('\n')
    248              if strip(doc.text):
    249                  parts.append(' '*indent)
    250                  parts.append(self.format_text(doc.text))
    251                  parts.append('\n')
    252              for el in doc:
    253                  parts.append(self.format_doc(el, html, indent+2))
    254              parts.append(' '*indent)
    255              parts.append(self.format_end_tag(doc))
    256              parts.append('\n')
    257          if strip(doc.tail):
    258              parts.append(' '*indent)
    259              parts.append(self.format_text(doc.tail))
    260              parts.append('\n')
    261          return ''.join(parts)
    262
    263 -    def format_text(self, text, strip=True):
    264          if text is None:
    265              return ''
    266          if strip:
    267              text = text.strip()
    268          return cgi.escape(text, 1)
    269
    270 -    def format_tag(self, el):
    271          attrs = []
    272          if isinstance(el, etree.CommentBase):
    273              # FIXME: probably PIs should be handled specially too?
    274              return '<!--'
    275          for name, value in sorted(el.attrib.items()):
    276              attrs.append('%s="%s"' % (name, self.format_text(value, False)))
    277          if not attrs:
    278              return '<%s>' % el.tag
    279          return '<%s %s>' % (el.tag, ' '.join(attrs))
    280
    281 -    def format_end_tag(self, el):
    282          if isinstance(el, etree.CommentBase):
    283              # FIXME: probably PIs should be handled specially too?
    284              return '-->'
    285          return '</%s>' % el.tag
    286
    287 -    def collect_diff(self, want, got, html, indent):
    288          parts = []
    289          if not len(want) and not len(got):
    290              parts.append(' '*indent)
    291              parts.append(self.collect_diff_tag(want, got))
    292              if not self.html_empty_tag(got, html):
    293                  parts.append(self.collect_diff_text(want.text, got.text))
    294                  parts.append(self.collect_diff_end_tag(want, got))
    295              parts.append(self.collect_diff_text(want.tail, got.tail))
    296              parts.append('\n')
    297              return ''.join(parts)
    298          parts.append(' '*indent)
    299          parts.append(self.collect_diff_tag(want, got))
    300          parts.append('\n')
    301          if strip(want.text) or strip(got.text):
    302              parts.append(' '*indent)
    303              parts.append(self.collect_diff_text(want.text, got.text))
    304              parts.append('\n')
    305          want_children = list(want)
    306          got_children = list(got)
    307          while want_children or got_children:
    308              if not want_children:
    309                  parts.append(self.format_doc(got_children.pop(0), html, indent+2, '-'))
    310                  continue
    311              if not got_children:
    312                  parts.append(self.format_doc(want_children.pop(0), html, indent+2, '+'))
    313                  continue
    314              parts.append(self.collect_diff(
    315                  want_children.pop(0), got_children.pop(0), html, indent+2))
    316          parts.append(' '*indent)
    317          parts.append(self.collect_diff_end_tag(want, got))
    318          parts.append('\n')
    319          if strip(want.tail) or strip(got.tail):
    320              parts.append(' '*indent)
    321              parts.append(self.collect_diff_text(want.tail, got.tail))
    322              parts.append('\n')
    323          return ''.join(parts)
    324
    325 -    def collect_diff_tag(self, want, got):
    326          if not self.tag_compare(want.tag, got.tag):
    327              tag = '%s (got: %s)' % (want.tag, got.tag)
    328          else:
    329              tag = got.tag
    330          attrs = []
    331          any = want.tag == 'any' or 'any' in want.attrib
    332          for name, value in sorted(got.attrib.items()):
    333              if name not in want.attrib and not any:
    334                  attrs.append('-%s="%s"' % (name, self.format_text(value, False)))
    335              else:
    336                  if name in want.attrib:
    337                      text = self.collect_diff_text(value, want.attrib[name], False)
    338                  else:
    339                      text = self.format_text(value, False)
    340                  attrs.append('%s="%s"' % (name, text))
    341          if not any:
    342              for name, value in sorted(want.attrib.items()):
    343                  if name in got.attrib:
    344                      continue
    345                  attrs.append('+%s="%s"' % (name, self.format_text(value, False)))
    346          if attrs:
    347              tag = '<%s %s>' % (tag, ' '.join(attrs))
    348          else:
    349              tag = '<%s>' % tag
    350          return tag
    351
    352 -    def collect_diff_end_tag(self, want, got):
    353          if want.tag != got.tag:
    354              tag = '%s (got: %s)' % (want.tag, got.tag)
    355          else:
    356              tag = got.tag
    357          return '</%s>' % tag
    358
    359 -    def collect_diff_text(self, want, got, strip=True):
    360          if self.text_compare(want, got, strip):
    361              if not got:
    362                  return ''
    363              return self.format_text(got, strip)
    364          text = '%s (got: %s)' % (want, got)
    365          return self.format_text(text, strip)
    366
    367 -class LHTMLOutputChecker(LXMLOutputChecker):
    368 -    def get_default_parser(self):
    369          return html_fromstring
    370
    371 -def install(html=False):
    372      """
    373      Install doctestcompare for all future doctests.
    374
    375      If html is true, then by default the HTML parser will be used;
    376      otherwise the XML parser is used.
    377      """
    378      if html:
    379          doctest.OutputChecker = LHTMLOutputChecker
    380      else:
    381          doctest.OutputChecker = LXMLOutputChecker
    382
    383 -def temp_install(html=False, del_module=None):
    384      """
    385      Use this *inside* a doctest to enable this checker for this
    386      doctest only.
    387
    388      If html is true, then by default the HTML parser will be used;
    389      otherwise the XML parser is used.
    390      """
    391      if html:
    392          Checker = LHTMLOutputChecker
    393      else:
    394          Checker = LXMLOutputChecker
    395      frame = _find_doctest_frame()
    396      dt_self = frame.f_locals['self']
    397      checker = Checker()
    398      old_checker = dt_self._checker
    399      dt_self._checker = checker
    400      # The unfortunate thing is that there is a local variable 'check'
    401      # in the function that runs the doctests, that is a bound method
    402      # into the output checker.  We have to update that.  We can't
    403      # modify the frame, so we have to modify the object in place.  The
    404      # only way to do this is to actually change the func_code
    405      # attribute of the method.  We change it, and then wait for
    406      # __record_outcome to be run, which signals the end of the __run
    407      # method, at which point we restore the previous check_output
    408      # implementation.
    409      if _IS_PYTHON_3:
    410          check_func = frame.f_locals['check'].__func__
    411          checker_check_func = checker.check_output.__func__
    412      else:
    413          check_func = frame.f_locals['check'].im_func
    414          checker_check_func = checker.check_output.im_func
    415      # Because we can't patch up func_globals, this is the only global
    416      # in check_output that we care about:
    417      doctest.etree = etree
    418      _RestoreChecker(dt_self, old_checker, checker,
    419                      check_func, checker_check_func,
    420                      del_module)
    421
    422 -class _RestoreChecker(object):
    423 -    def __init__(self, dt_self, old_checker, new_checker, check_func, clone_func,
    424                   del_module):
    425          self.dt_self = dt_self
    426          self.checker = old_checker
    427          self.checker._temp_call_super_check_output = self.call_super
    428          self.checker._temp_override_self = new_checker
    429          self.check_func = check_func
    430          self.clone_func = clone_func
    431          self.del_module = del_module
    432          self.install_clone()
    433          self.install_dt_self()
    434 -    def install_clone(self):
    435          if _IS_PYTHON_3:
    436              self.func_code = self.check_func.__code__
    437              self.func_globals = self.check_func.__globals__
    438              self.check_func.__code__ = self.clone_func.__code__
    439          else:
    440              self.func_code = self.check_func.func_code
    441              self.func_globals = self.check_func.func_globals
    442              self.check_func.func_code = self.clone_func.func_code
    443 -    def uninstall_clone(self):
    444          if _IS_PYTHON_3:
    445              self.check_func.__code__ = self.func_code
    446          else:
    447              self.check_func.func_code = self.func_code
    448 -    def install_dt_self(self):
    449          self.prev_func = self.dt_self._DocTestRunner__record_outcome
    450          self.dt_self._DocTestRunner__record_outcome = self
    451 -    def uninstall_dt_self(self):
    452          self.dt_self._DocTestRunner__record_outcome = self.prev_func
    453 -    def uninstall_module(self):
    454          if self.del_module:
    455              import sys
    456              del sys.modules[self.del_module]
    457              if '.' in self.del_module:
    458                  package, module = self.del_module.rsplit('.', 1)
    459                  package_mod = sys.modules[package]
    460                  delattr(package_mod, module)
    461 -    def __call__(self, *args, **kw):
    462          self.uninstall_clone()
    463          self.uninstall_dt_self()
    464          del self.checker._temp_override_self
    465          del self.checker._temp_call_super_check_output
    466          result = self.prev_func(*args, **kw)
    467          self.uninstall_module()
    468          return result
    469 -    def call_super(self, *args, **kw):
    470          self.uninstall_clone()
    471          try:
    472              return self.check_func(*args, **kw)
    473          finally:
    474              self.install_clone()
    475
    476 -def _find_doctest_frame():
    477      import sys
    478      frame = sys._getframe(1)
    479      while frame:
    480          l = frame.f_locals
    481          if 'BOOM' in l:
    482              # Sign of doctest
    483              return frame
    484          frame = frame.f_back
    485      raise LookupError(
    486          "Could not find doctest (only use this function *inside* a doctest)")
    487
    488  __test__ = {
    489      'basic': '''
    490      >>> temp_install()
    491      >>> print """<xml a="1" b="2">stuff</xml>"""
    492      <xml b="2" a="1">...</xml>
    493      >>> print """<xml xmlns="http://example.com"><tag   attr="bar"   /></xml>"""
    494      <xml xmlns="...">
    495        <tag attr="..." />
    496      </xml>
    497      >>> print """<xml>blahblahblah<foo /></xml>""" # doctest: +NOPARSE_MARKUP, +ELLIPSIS
    498      <xml>...foo /></xml>
    499      '''}
    500
    501  if __name__ == '__main__':
    502      import doctest
    503      doctest.testmod()
    504