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