Merge pull request #183 from mailgun/sergey/date

fix text with Date: misclassified as quotations splitter

.gitignore

@@ -39,6 +39,8 @@ nosetests.xml
 /.emacs.desktop
 /.emacs.desktop.lock
 .elc
+.idea
+.cache
 auto-save-list
 tramp
 .\#*

README.rst

@@ -129,6 +129,22 @@ start using it for talon.
 .. _EDRM: http://www.edrm.net/resources/data-sets/edrm-enron-email-data-set
 .. _forge: https://github.com/mailgun/forge
 
+Training on your dataset
+------------------------
+
+talon comes with a pre-processed dataset and a pre-trained classifier. To retrain the classifier on your own dataset of raw emails, structure and annotate them in the same way the `forge`_ project does. Then do:
+
+.. code:: python
+
+    from talon.signature.learning.dataset import build_extraction_dataset
+    from talon.signature.learning import classifier as c 
+    
+    build_extraction_dataset("/path/to/your/P/folder", "/path/to/talon/signature/data/train.data")
+    c.train(c.init(), "/path/to/talon/signature/data/train.data", "/path/to/talon/signature/data/classifier")
+
+Note that for signature extraction you need just the folder with the positive samples with annotated signature lines (P folder).
+
+.. _forge: https://github.com/mailgun/forge
 
 Research
 --------

setup.py

@@ -29,7 +29,7 @@ class InstallCommand(install):
 
 
 setup(name='talon',
-      version='1.2.15',
+      version='1.4.7',
       description=("Mailgun library "
                    "to extract message quotations and signatures."),
       long_description=open("README.rst").read(),
@@ -48,11 +48,12 @@ setup(name='talon',
           "regex>=1",
           "numpy",
           "scipy",
-          "scikit-learn==0.16.1", # pickled versions of classifier, else rebuild
+          "scikit-learn>=0.16.1", # pickled versions of classifier, else rebuild
           'chardet>=1.0.1',
           'cchardet>=0.3.5',
           'cssselect',
           'six>=1.10.0',
+          'html5lib'
           ],
       tests_require=[
           "mock",

talon/html_quotations.py

@@ -6,6 +6,7 @@ messages (without quoted messages) from html
 from __future__ import absolute_import
 import regex as re
 
+from talon.utils import cssselect 
 
 CHECKPOINT_PREFIX = '#!%!'
 CHECKPOINT_SUFFIX = '!%!#'
@@ -78,7 +79,7 @@ def delete_quotation_tags(html_note, counter, quotation_checkpoints):
 
 def cut_gmail_quote(html_message):
     ''' Cuts the outermost block element with class gmail_quote. '''
-    gmail_quote = html_message.cssselect('div.gmail_quote')
+    gmail_quote = cssselect('div.gmail_quote', html_message)
     if gmail_quote and (gmail_quote[0].text is None or not RE_FWD.match(gmail_quote[0].text)):
         gmail_quote[0].getparent().remove(gmail_quote[0])
         return True
@@ -86,17 +87,24 @@ def cut_gmail_quote(html_message):
 
 def cut_microsoft_quote(html_message):
     ''' Cuts splitter block and all following blocks. '''
+    #use EXSLT extensions to have a regex match() function with lxml
+    ns = {"re": "http://exslt.org/regular-expressions"}
+
+    #general pattern: @style='border:none;border-top:solid <color> 1.0pt;padding:3.0pt 0<unit> 0<unit> 0<unit>'
+    #outlook 2007, 2010 (international) <color=#B5C4DF> <unit=cm>
+    #outlook 2007, 2010 (american)      <color=#B5C4DF> <unit=pt>
+    #outlook 2013       (international) <color=#E1E1E1> <unit=cm>
+    #outlook 2013       (american)      <color=#E1E1E1> <unit=pt>
+    #also handles a variant with a space after the semicolon
     splitter = html_message.xpath(
-        #outlook 2007, 2010 (international)
+        #outlook 2007, 2010, 2013 (international, american)
-        "//div[@style='border:none;border-top:solid #B5C4DF 1.0pt;"
+        "//div[@style[re:match(., 'border:none; ?border-top:solid #(E1E1E1|B5C4DF) 1.0pt; ?"
-        "padding:3.0pt 0cm 0cm 0cm']|"
+        "padding:3.0pt 0(in|cm) 0(in|cm) 0(in|cm)')]]|"
-        #outlook 2007, 2010 (american)
-        "//div[@style='border:none;border-top:solid #B5C4DF 1.0pt;"
-        "padding:3.0pt 0in 0in 0in']|"
         #windows mail
         "//div[@style='padding-top: 5px; "
         "border-top-color: rgb(229, 229, 229); "
         "border-top-width: 1px; border-top-style: solid;']"
+        , namespaces=ns
     )
 
     if splitter:
@@ -135,7 +143,7 @@ def cut_microsoft_quote(html_message):
 def cut_by_id(html_message):
     found = False
     for quote_id in QUOTE_IDS:
-        quote = html_message.cssselect('#{}'.format(quote_id))
+        quote = cssselect('#{}'.format(quote_id), html_message)
         if quote:
             found = True
             quote[0].getparent().remove(quote[0])

talon/quotations.py

@@ -12,7 +12,8 @@ from copy import deepcopy
 
 from lxml import html, etree
 
-from talon.utils import get_delimiter, html_tree_to_text
+from talon.utils import (get_delimiter, html_tree_to_text,
+                         html_document_fromstring)
 from talon import html_quotations
 from six.moves import range
 import six
@@ -21,7 +22,7 @@ import six
 log = logging.getLogger(__name__)
 
 
-RE_FWD = re.compile("^[-]+[ ]*Forwarded message[ ]*[-]+$", re.I | re.M)
+RE_FWD = re.compile("^[-]+[ ]*Forwarded message[ ]*[-]+\s*$", re.I | re.M)
 
 RE_ON_DATE_SMB_WROTE = re.compile(
     u'(-*[>]?[ ]?({0})[ ].*({1})(.*\n){{0,2}}.*({2}):?-*)'.format(
@@ -37,10 +38,14 @@ RE_ON_DATE_SMB_WROTE = re.compile(
             'Op',
             # German
             'Am',
+            # Portuguese
+            'Em',
             # Norwegian
             u'På',
             # Swedish, Danish
             'Den',
+            # Vietnamese
+            u'Vào',
         )),
         # Date and sender separator
         u'|'.join((
@@ -61,8 +66,12 @@ RE_ON_DATE_SMB_WROTE = re.compile(
             'schreef','verzond','geschreven',
             # German
             'schrieb',
+            # Portuguese
+            'escreveu',
             # Norwegian, Swedish
             'skrev',
+            # Vietnamese
+            u'đã viết',
         ))
     ))
 # Special case for languages where text is translated like this: 'on {date} wrote {somebody}:'
@@ -130,14 +139,33 @@ RE_ORIGINAL_MESSAGE = re.compile(u'[\s]*[-]+[ ]*({})[ ]*[-]+'.format(
         'Oprindelig meddelelse',
     ))), re.I)
 
-RE_FROM_COLON_OR_DATE_COLON = re.compile(u'(_+\r?\n)?[\s]*(:?[*]?{})[\s]?:[*]? .*'.format(
+RE_FROM_COLON_OR_DATE_COLON = re.compile(u'((_+\r?\n)?[\s]*:?[*]?({})[\s]?:([^\n$]+\n){{1,2}}){{2,}}'.format(
     u'|'.join((
         # "From" in different languages.
         'From', 'Van', 'De', 'Von', 'Fra', u'Från',
         # "Date" in different languages.
-        'Date', 'Datum', u'Envoyé', 'Skickat', 'Sendt',
+        'Date', '[S]ent', 'Datum', u'Envoyé', 'Skickat', 'Sendt', 'Gesendet',
+        # "Subject" in different languages.
+        'Subject', 'Betreff', 'Objet', 'Emne', u'Ämne',
+        # "To" in different languages.
+        'To', 'An', 'Til', u'À', 'Till'
+    ))), re.I | re.M)
+
+# ---- John Smith wrote ----
+RE_ANDROID_WROTE = re.compile(u'[\s]*[-]+.*({})[ ]*[-]+'.format(
+    u'|'.join((
+        # English
+        'wrote',
     ))), re.I)
 
+# Support polymail.io reply format
+# On Tue, Apr 11, 2017 at 10:07 PM John Smith
+#
+# <
+# mailto:John Smith <johnsmith@gmail.com>
+# > wrote:
+RE_POLYMAIL = re.compile('On.*\s{2}<\smailto:.*\s> wrote:', re.I)
+
 SPLITTER_PATTERNS = [
     RE_ORIGINAL_MESSAGE,
     RE_ON_DATE_SMB_WROTE,
@@ -145,24 +173,25 @@ SPLITTER_PATTERNS = [
     RE_FROM_COLON_OR_DATE_COLON,
     # 02.04.2012 14:20 пользователь "bob@example.com" <
     # bob@xxx.mailgun.org> написал:
-    re.compile("(\d+/\d+/\d+|\d+\.\d+\.\d+).*@", re.S),
+    re.compile("(\d+/\d+/\d+|\d+\.\d+\.\d+).*\s\S+@\S+", re.S),
     # 2014-10-17 11:28 GMT+03:00 Bob <
     # bob@example.com>:
-    re.compile("\d{4}-\d{2}-\d{2}\s+\d{2}:\d{2}\s+GMT.*@", re.S),
+    re.compile("\d{4}-\d{2}-\d{2}\s+\d{2}:\d{2}\s+GMT.*\s\S+@\S+", re.S),
     # Thu, 26 Jun 2014 14:00:51 +0400 Bob <bob@example.com>:
     re.compile('\S{3,10}, \d\d? \S{3,10} 20\d\d,? \d\d?:\d\d(:\d\d)?'
                '( \S+){3,6}@\S+:'),
     # Sent from Samsung MobileName <address@example.com> wrote:
-    re.compile('Sent from Samsung .*@.*> wrote')
+    re.compile('Sent from Samsung.* \S+@\S+> wrote'),
+    RE_ANDROID_WROTE,
+    RE_POLYMAIL
     ]
 
-
 RE_LINK = re.compile('<(http://[^>]*)>')
 RE_NORMALIZED_LINK = re.compile('@@(http://[^>@]*)@@')
 
 RE_PARENTHESIS_LINK = re.compile("\(https?://")
 
-SPLITTER_MAX_LINES = 4
+SPLITTER_MAX_LINES = 6
 MAX_LINES_COUNT = 1000
 # an extensive research shows that exceeding this limit
 # leads to excessive processing time
@@ -171,6 +200,9 @@ MAX_HTML_LEN = 2794202
 QUOT_PATTERN = re.compile('^>+ ?')
 NO_QUOT_LINE = re.compile('^[^>].*[\S].*')
 
+# Regular expression to identify if a line is a header.
+RE_HEADER = re.compile(": ")
+
 
 def extract_from(msg_body, content_type='text/plain'):
     try:
@@ -184,6 +216,19 @@ def extract_from(msg_body, content_type='text/plain'):
     return msg_body
 
 
+def remove_initial_spaces_and_mark_message_lines(lines):
+    """
+    Removes the initial spaces in each line before marking message lines.
+
+    This ensures headers can be identified if they are indented with spaces.
+    """
+    i = 0
+    while i < len(lines):
+        lines[i] = lines[i].lstrip(' ')
+        i += 1
+    return mark_message_lines(lines)
+
+
 def mark_message_lines(lines):
     """Mark message lines with markers to distinguish quotation lines.
 
@@ -249,7 +294,7 @@ def process_marked_lines(lines, markers, return_flags=[False, -1, -1]):
     # inlined reply
     # use lookbehind assertions to find overlapping entries e.g. for 'mtmtm'
     # both 't' entries should be found
-    for inline_reply in re.finditer('(?<=m)e*((?:t+e*)+)m', markers):
+    for inline_reply in re.finditer('(?<=m)e*(t[te]*)m', markers):
         # long links could break sequence of quotation lines but they shouldn't
         # be considered an inline reply
         links = (
@@ -286,9 +331,21 @@ def preprocess(msg_body, delimiter, content_type='text/plain'):
 
     Converts msg_body into a unicode.
     """
-    # normalize links i.e. replace '<', '>' wrapping the link with some symbols
+    msg_body = _replace_link_brackets(msg_body)
-    # so that '>' closing the link couldn't be mistakenly taken for quotation
+
-    # marker.
+    msg_body = _wrap_splitter_with_newline(msg_body, delimiter, content_type)
+
+    return msg_body
+
+
+def _replace_link_brackets(msg_body):
+    """
+    Normalize links i.e. replace '<', '>' wrapping the link with some symbols
+    so that '>' closing the link couldn't be mistakenly taken for quotation
+    marker.
+
+    Converts msg_body into a unicode
+    """
     if isinstance(msg_body, bytes):
         msg_body = msg_body.decode('utf8')
 
@@ -300,7 +357,14 @@ def preprocess(msg_body, delimiter, content_type='text/plain'):
             return "@@%s@@" % link.group(1)
 
     msg_body = re.sub(RE_LINK, link_wrapper, msg_body)
+    return msg_body
 
+
+def _wrap_splitter_with_newline(msg_body, delimiter, content_type='text/plain'):
+    """
+    Splits line in two if splitter pattern preceded by some text on the same
+    line (done only for 'On <date> <person> wrote:' pattern.
+    """
     def splitter_wrapper(splitter):
         """Wraps splitter with new line"""
         if splitter.start() and msg_body[splitter.start() - 1] != '\n':
@@ -374,6 +438,9 @@ def _extract_from_html(msg_body):
     Extract not quoted message from provided html message body
     using tags and plain text algorithm.
 
+    Cut out first some encoding html tags such as xml and doctype
+    for avoiding conflict with unicode decoding
+
     Cut out the 'blockquote', 'gmail_quote' tags.
     Cut Microsoft quotations.
 
@@ -385,17 +452,18 @@ def _extract_from_html(msg_body):
     then checking deleted checkpoints,
     then deleting necessary tags.
     """
-    if len(msg_body) > MAX_HTML_LEN:
-        return msg_body
-
     if msg_body.strip() == b'':
         return msg_body
 
     msg_body = msg_body.replace(b'\r\n', b'\n')
-    html_tree = html.document_fromstring(
+
-        msg_body,
+    msg_body = re.sub(r"\<\?xml.+\?\>|\<\!DOCTYPE.+]\>", "", msg_body)
-        parser=html.HTMLParser(encoding="utf-8")
+
-    )
+    html_tree = html_document_fromstring(msg_body)
+
+    if html_tree is None:
+        return msg_body
+
     cut_quotations = (html_quotations.cut_gmail_quote(html_tree) or
                       html_quotations.cut_zimbra_quote(html_tree) or
                       html_quotations.cut_blockquote(html_tree) or
@@ -451,6 +519,81 @@ def _extract_from_html(msg_body):
     return html.tostring(html_tree_copy)
 
 
+def split_emails(msg):
+    """
+    Given a message (which may consist of an email conversation thread with
+    multiple emails), mark the lines to identify split lines, content lines and
+    empty lines.
+
+    Correct the split line markers inside header blocks. Header blocks are
+    identified by the regular expression RE_HEADER.
+
+    Return the corrected markers
+    """
+    msg_body = _replace_link_brackets(msg)
+
+    # don't process too long messages
+    lines = msg_body.splitlines()[:MAX_LINES_COUNT]
+    markers = remove_initial_spaces_and_mark_message_lines(lines)
+
+    markers = _mark_quoted_email_splitlines(markers, lines)
+
+    # we don't want splitlines in header blocks
+    markers = _correct_splitlines_in_headers(markers, lines)
+
+    return markers
+
+
+def _mark_quoted_email_splitlines(markers, lines):
+    """
+    When there are headers indented with '>' characters, this method will
+    attempt to identify if the header is a splitline header. If it is, then we
+    mark it with 's' instead of leaving it as 'm' and return the new markers.
+    """
+    # Create a list of markers to easily alter specific characters
+    markerlist = list(markers)
+    for i, line in enumerate(lines):
+        if markerlist[i] != 'm':
+            continue
+        for pattern in SPLITTER_PATTERNS:
+            matcher = re.search(pattern, line)
+            if matcher:
+                markerlist[i] = 's'
+                break
+
+    return "".join(markerlist)
+
+
+def _correct_splitlines_in_headers(markers, lines):
+    """
+    Corrects markers by removing splitlines deemed to be inside header blocks.
+    """
+    updated_markers = ""
+    i = 0
+    in_header_block = False
+    for m in markers:
+        # Only set in_header_block flag when we hit an 's' and line is a header
+        if m == 's':
+            if not in_header_block:
+                if bool(re.search(RE_HEADER, lines[i])):
+                    in_header_block = True
+            else:
+                if QUOT_PATTERN.match(lines[i]):
+                    m = 'm'
+                else:
+                    m = 't'
+
+        # If the line is not a header line, set in_header_block false.
+        if not bool(re.search(RE_HEADER, lines[i])):
+            in_header_block = False
+
+        # Add the marker to the new updated markers string.
+        updated_markers += m
+        i += 1
+
+    return updated_markers
+
+
 def _readable_text_empty(html_tree):
     return not bool(html_tree_to_text(html_tree).strip())
 
@@ -468,7 +611,7 @@ def is_splitter(line):
 
 def text_content(context):
     '''XPath Extension function to return a node text content.'''
-    return context.context_node.text_content().strip()
+    return context.context_node.xpath("string()").strip()
 
 
 def tail(context):

talon/signature/bruteforce.py

@@ -1,15 +1,15 @@
 from __future__ import absolute_import
+
 import logging
 
 import regex as re
 
-from talon.utils import get_delimiter
 from talon.signature.constants import (SIGNATURE_MAX_LINES,
                                        TOO_LONG_SIGNATURE_LINE)
+from talon.utils import get_delimiter
 
 log = logging.getLogger(__name__)
 
-
 # regex to fetch signature based on common signature words
 RE_SIGNATURE = re.compile(r'''
                (
@@ -28,7 +28,6 @@ RE_SIGNATURE = re.compile(r'''
                )
                ''', re.I | re.X | re.M | re.S)
 
-
 # signatures appended by phone email clients
 RE_PHONE_SIGNATURE = re.compile(r'''
                (
@@ -45,7 +44,6 @@ RE_PHONE_SIGNATURE = re.compile(r'''
                )
                ''', re.I | re.X | re.M | re.S)
 
-
 # see _mark_candidate_indexes() for details
 # c - could be signature line
 # d - line starts with dashes (could be signature or list item)
@@ -112,7 +110,7 @@ def extract_signature(msg_body):
 
             return (stripped_body.strip(),
                     signature.strip())
-    except Exception as e:
+    except Exception:
         log.exception('ERROR extracting signature')
         return (msg_body, None)
 
@@ -163,7 +161,7 @@ def _mark_candidate_indexes(lines, candidate):
     'cdc'
     """
     # at first consider everything to be potential signature lines
-    markers = bytearray('c'*len(candidate))
+    markers = list('c' * len(candidate))
 
     # mark lines starting from bottom up
     for i, line_idx in reversed(list(enumerate(candidate))):
@@ -174,7 +172,7 @@ def _mark_candidate_indexes(lines, candidate):
             if line.startswith('-') and line.strip("-"):
                 markers[i] = 'd'
 
-    return markers
+    return "".join(markers)
 
 
 def _process_marked_candidate_indexes(candidate, markers):

talon/signature/extraction.py

@@ -1,16 +1,15 @@
 # -*- coding: utf-8 -*-
 
 from __future__ import absolute_import
+
 import logging
 
-import regex as re
 import numpy
-
+import regex as re
-from talon.signature.learning.featurespace import features, build_pattern
-from talon.utils import get_delimiter
 from talon.signature.bruteforce import get_signature_candidate
+from talon.signature.learning.featurespace import features, build_pattern
 from talon.signature.learning.helpers import has_signature
-
+from talon.utils import get_delimiter
 
 log = logging.getLogger(__name__)
 
@@ -33,7 +32,7 @@ RE_REVERSE_SIGNATURE = re.compile(r'''
 
 def is_signature_line(line, sender, classifier):
     '''Checks if the line belongs to signature. Returns True or False.'''
-    data = numpy.array(build_pattern(line, features(sender)))
+    data = numpy.array(build_pattern(line, features(sender))).reshape(1, -1)
     return classifier.predict(data) > 0
 
 
@@ -58,7 +57,7 @@ def extract(body, sender):
                 text = delimiter.join(text)
                 if text.strip():
                     return (text, delimiter.join(signature))
-    except Exception:
+    except Exception as e:
         log.exception('ERROR when extracting signature with classifiers')
 
     return (body, None)
@@ -81,7 +80,7 @@ def _mark_lines(lines, sender):
     candidate = get_signature_candidate(lines)
 
     # at first consider everything to be text no signature
-    markers = bytearray('t'*len(lines))
+    markers = list('t' * len(lines))
 
     # mark lines starting from bottom up
     # mark only lines that belong to candidate
@@ -96,7 +95,7 @@ def _mark_lines(lines, sender):
         elif is_signature_line(line, sender, EXTRACTOR):
             markers[j] = 's'
 
-    return markers
+    return "".join(markers)
 
 
 def _process_marked_lines(lines, markers):
@@ -111,3 +110,4 @@ def _process_marked_lines(lines, markers):
         return (lines[:-signature.end()], lines[-signature.end():])
 
     return (lines, None)
+

talon/signature/learning/classifier.py

@@ -6,9 +6,10 @@ body belongs to the signature.
 """
 
 from __future__ import absolute_import
+
 from numpy import genfromtxt
-from sklearn.svm import LinearSVC
 from sklearn.externals import joblib
+from sklearn.svm import LinearSVC
 
 
 def init():
@@ -29,4 +30,40 @@ def train(classifier, train_data_filename, save_classifier_filename=None):
 
 def load(saved_classifier_filename, train_data_filename):
     """Loads saved classifier. """
+    try:
         return joblib.load(saved_classifier_filename)
+    except Exception:
+        import sys
+        if sys.version_info > (3, 0):
+            return load_compat(saved_classifier_filename)
+
+        raise
+
+
+def load_compat(saved_classifier_filename):
+    import os
+    import pickle
+    import tempfile
+
+    # we need to switch to the data path to properly load the related _xx.npy files
+    cwd = os.getcwd()
+    os.chdir(os.path.dirname(saved_classifier_filename))
+
+    # convert encoding using pick.load and write to temp file which we'll tell joblib to use
+    pickle_file = open(saved_classifier_filename, 'rb')
+    classifier = pickle.load(pickle_file, encoding='latin1')
+
+    try:
+        # save our conversion if permissions allow
+        joblib.dump(classifier, saved_classifier_filename)
+    except Exception:
+        # can't write to classifier, use a temp file
+        tmp = tempfile.SpooledTemporaryFile()
+        joblib.dump(classifier, tmp)
+        saved_classifier_filename = tmp
+
+    # important, use joblib.load before switching back to original cwd
+    jb_classifier = joblib.load(saved_classifier_filename)
+    os.chdir(cwd)
+
+    return jb_classifier

talon/signature/learning/dataset.py

@@ -17,13 +17,14 @@ suffix which should be `_sender`.
 """
 
 from __future__ import absolute_import
+
 import os
+
 import regex as re
+from six.moves import range
 
 from talon.signature.constants import SIGNATURE_MAX_LINES
 from talon.signature.learning.featurespace import build_pattern, features
-from six.moves import range
-
 
 SENDER_SUFFIX = '_sender'
 BODY_SUFFIX = '_body'
@@ -57,9 +58,14 @@ def parse_msg_sender(filename, sender_known=True):
     algorithm:
     >>> parse_msg_sender(filename, False)
     """
+    import sys
+    kwargs = {}
+    if sys.version_info > (3, 0):
+        kwargs["encoding"] = "utf8"
+
     sender, msg = None, None
     if os.path.isfile(filename) and not is_sender_filename(filename):
-        with open(filename) as f:
+        with open(filename, **kwargs) as f:
             msg = f.read()
             sender = u''
             if sender_known:

talon/utils.py

@@ -1,17 +1,18 @@
 # coding:utf-8
 
 from __future__ import absolute_import
-import logging
-from random import shuffle
-import chardet
-import cchardet
-import regex as re
 
-from lxml import html
+from random import shuffle
+
+import cchardet
+import chardet
+import html5lib
+import regex as re
+import six
 from lxml.cssselect import CSSSelector
+from lxml.html import html5parser
 
 from talon.constants import RE_DELIMITER
-import six
 
 
 def safe_format(format_string, *args, **kwargs):
@@ -112,18 +113,25 @@ def get_delimiter(msg_body):
 
     return delimiter
 
+
 def html_tree_to_text(tree):
     for style in CSSSelector('style')(tree):
         style.getparent().remove(style)
 
     for c in tree.xpath('//comment()'):
-        c.getparent().remove(c)
+        parent = c.getparent()
+
+        # comment with no parent does not impact produced text
+        if parent is None:
+            continue
+
+        parent.remove(c)
 
     text = ""
     for el in tree.iter():
         el_text = (el.text or '') + (el.tail or '')
         if len(el_text) > 1:
-            if el.tag in _BLOCKTAGS:
+            if el.tag in _BLOCKTAGS + _HARDBREAKS:
                 text += "\n"
             if el.tag == 'li':
                 text += "  * "
@@ -134,7 +142,8 @@ def html_tree_to_text(tree):
             if href:
                 text += "(%s) " % href
 
-        if el.tag in _HARDBREAKS and text and not text.endswith("\n"):
+        if (el.tag in _HARDBREAKS and text and
+            not text.endswith("\n") and not el_text):
             text += "\n"
 
     retval = _rm_excessive_newlines(text)
@@ -150,17 +159,59 @@ def html_to_text(string):
     NOTES:
         1. the string is expected to contain UTF-8 encoded HTML!
         2. returns utf-8 encoded str (not unicode)
+        3. if html can't be parsed returns None
     """
     if isinstance(string, six.text_type):
         string = string.encode('utf8')
 
     s = _prepend_utf8_declaration(string)
     s = s.replace(b"\n", b"")
+    tree = html_fromstring(s)
+
+    if tree is None:
+        return None
 
-    tree = html.fromstring(s)
     return html_tree_to_text(tree)
 
 
+def html_fromstring(s):
+    """Parse html tree from string. Return None if the string can't be parsed.
+    """
+    if isinstance(s, six.text_type):
+        s = s.encode('utf8')
+    try:
+        if html_too_big(s):
+            return None
+
+        return html5parser.fromstring(s, parser=_html5lib_parser())
+    except Exception:
+        pass
+
+
+def html_document_fromstring(s):
+    """Parse html tree from string. Return None if the string can't be parsed.
+    """
+    if isinstance(s, six.text_type):
+        s = s.encode('utf8')
+    try:
+        if html_too_big(s):
+            return None
+
+        return html5parser.document_fromstring(s, parser=_html5lib_parser())
+    except Exception:
+        pass
+
+
+def cssselect(expr, tree):
+    return CSSSelector(expr)(tree)
+
+
+def html_too_big(s):
+    if isinstance(s, six.text_type):
+        s = s.encode('utf8')
+    return s.count(b'<') > _MAX_TAGS_COUNT
+
+
 def _contains_charset_spec(s):
     """Return True if the first 4KB contain charset spec
     """
@@ -185,12 +236,29 @@ def _encode_utf8(s):
     return s.encode('utf-8') if isinstance(s, six.text_type) else s
 
 
+def _html5lib_parser():
+    """
+    html5lib is a pure-python library that conforms to the WHATWG HTML spec
+    and is not vulnarable to certain attacks common for XML libraries
+    """
+    return html5lib.HTMLParser(
+        # build lxml tree
+        html5lib.treebuilders.getTreeBuilder("lxml"),
+        # remove namespace value from inside lxml.html.html5paser element tag
+        # otherwise it yields something like "{http://www.w3.org/1999/xhtml}div"
+        # instead of "div", throwing the algo off
+        namespaceHTMLElements=False
+    )
+
+
 _UTF8_DECLARATION = (b'<meta http-equiv="Content-Type" content="text/html;'
                      b'charset=utf-8">')
 
-
 _BLOCKTAGS = ['div', 'p', 'ul', 'li', 'h1', 'h2', 'h3']
 _HARDBREAKS = ['br', 'hr', 'tr']
 
-
 _RE_EXCESSIVE_NEWLINES = re.compile("\n{2,10}")
+
+# an extensive research shows that exceeding this limit
+# might lead to excessive processing time
+_MAX_TAGS_COUNT = 419

tests/html_quotations_test.py

@@ -1,13 +1,13 @@
 # -*- coding: utf-8 -*-
 
 from __future__ import absolute_import
-from . import *
-from . fixtures import *
 
-import regex as re
+# noinspection PyUnresolvedReferences
+import re
 
 from talon import quotations, utils as u
-
+from . import *
+from .fixtures import *
 
 RE_WHITESPACE = re.compile("\s")
 RE_DOUBLE_WHITESPACE = re.compile("\s")
@@ -27,7 +27,7 @@ def test_quotation_splitter_inside_blockquote():
 
 </blockquote>"""
 
-    eq_("<html><body><p>Reply</p></body></html>",
+    eq_("<html><head></head><body>Reply</body></html>",
         RE_WHITESPACE.sub('', quotations.extract_from_html(msg_body)))
 
 
@@ -44,7 +44,7 @@ def test_quotation_splitter_outside_blockquote():
   </div>
 </blockquote>
 """
-    eq_("<html><body><p>Reply</p></body></html>",
+    eq_("<html><head></head><body>Reply</body></html>",
         RE_WHITESPACE.sub('', quotations.extract_from_html(msg_body)))
 
 
@@ -62,7 +62,7 @@ def test_regular_blockquote():
   </div>
 </blockquote>
 """
-    eq_("<html><body><p>Reply</p><blockquote>Regular</blockquote></body></html>",
+    eq_("<html><head></head><body>Reply<blockquote>Regular</blockquote></body></html>",
         RE_WHITESPACE.sub('', quotations.extract_from_html(msg_body)))
 
 
@@ -85,6 +85,7 @@ Reply
 
     reply = """
 <html>
+<head></head>
 <body>
 Reply
 
@@ -128,7 +129,7 @@ def test_gmail_quote():
     </div>
   </div>
 </div>"""
-    eq_("<html><body><p>Reply</p></body></html>",
+    eq_("<html><head></head><body>Reply</body></html>",
         RE_WHITESPACE.sub('', quotations.extract_from_html(msg_body)))
 
 
@@ -139,7 +140,7 @@ def test_gmail_quote_compact():
                '<div>Test</div>' \
                '</div>' \
                '</div>'
-    eq_("<html><body><p>Reply</p></body></html>",
+    eq_("<html><head></head><body>Reply</body></html>",
         RE_WHITESPACE.sub('', quotations.extract_from_html(msg_body)))
 
 
@@ -166,7 +167,7 @@ def test_unicode_in_reply():
   Quote
 </blockquote>""".encode("utf-8")
 
-    eq_("<html><body><p>Reply&#160;&#160;Text<br></p><div><br></div>"
+    eq_("<html><head></head><body>Reply&#160;&#160;Text<br><div><br></div>"
         "</body></html>",
         RE_WHITESPACE.sub('', quotations.extract_from_html(msg_body)))
 
@@ -192,6 +193,7 @@ def test_blockquote_disclaimer():
 
     stripped_html = """
 <html>
+  <head></head>
   <body>
   <div>
     <div>
@@ -223,7 +225,7 @@ def test_date_block():
   </div>
 </div>
 """
-    eq_('<html><body><div>message<br></div></body></html>',
+    eq_('<html><head></head><body><div>message<br></div></body></html>',
         RE_WHITESPACE.sub('', quotations.extract_from_html(msg_body)))
 
 
@@ -240,7 +242,7 @@ Subject: You Have New Mail From Mary!<br><br>
 text
 </div></div>
 """
-    eq_('<html><body><div>message<br></div></body></html>',
+    eq_('<html><head></head><body><div>message<br></div></body></html>',
         RE_WHITESPACE.sub('', quotations.extract_from_html(msg_body)))
 
 
@@ -258,7 +260,7 @@ def test_reply_shares_div_with_from_block():
 
   </div>
 </body>'''
-    eq_('<html><body><div>Blah<br><br></div></body></html>',
+    eq_('<html><head></head><body><div>Blah<br><br></div></body></html>',
         RE_WHITESPACE.sub('', quotations.extract_from_html(msg_body)))
 
 
@@ -269,13 +271,13 @@ def test_reply_quotations_share_block():
 
 
 def test_OLK_SRC_BODY_SECTION_stripped():
-    eq_('<html><body><div>Reply</div></body></html>',
+    eq_('<html><head></head><body><div>Reply</div></body></html>',
         RE_WHITESPACE.sub(
             '', quotations.extract_from_html(OLK_SRC_BODY_SECTION)))
 
 
 def test_reply_separated_by_hr():
-    eq_('<html><body><div>Hi<div>there</div></div></body></html>',
+    eq_('<html><head></head><body><div>Hi<div>there</div></div></body></html>',
         RE_WHITESPACE.sub(
             '', quotations.extract_from_html(REPLY_SEPARATED_BY_HR)))
 
@@ -296,12 +298,17 @@ Reply
   </div>
 </div>
 '''
-    eq_('<html><body><p>Reply</p><div><hr></div></body></html>',
+    eq_('<html><head></head><body>Reply<div><hr></div></body></html>',
         RE_WHITESPACE.sub('', quotations.extract_from_html(msg_body)))
 
 
 def extract_reply_and_check(filename):
-    f = open(filename)
+    import sys
+    kwargs = {}
+    if sys.version_info > (3, 0):
+        kwargs["encoding"] = "utf8"
+
+    f = open(filename, **kwargs)
 
     msg_body = f.read()
     reply = quotations.extract_from_html(msg_body)
@@ -373,7 +380,7 @@ reply
     extracted = quotations.extract_from_html(msg_body)
     assert_false(symbol in extracted)
     # Keep new lines otherwise "My reply" becomes one word - "Myreply" 
-    eq_("<html><body><p>My\nreply\n</p></body></html>", extracted)
+    eq_("<html><head></head><body>My\nreply\n</body></html>", extracted)
 
 
 def test_gmail_forwarded_msg():
@@ -383,7 +390,7 @@ def test_gmail_forwarded_msg():
     eq_(RE_WHITESPACE.sub('', msg_body), RE_WHITESPACE.sub('', extracted))
 
 
-@patch.object(quotations, 'MAX_HTML_LEN', 1)
+@patch.object(u, '_MAX_TAGS_COUNT', 4)
 def test_too_large_html():
     msg_body = 'Reply' \
                '<div class="gmail_quote">' \
@@ -411,3 +418,9 @@ def test_readable_html_empty():
 
     eq_(RE_WHITESPACE.sub('', msg_body),
         RE_WHITESPACE.sub('', quotations.extract_from_html(msg_body)))
+
+
+@patch.object(quotations, 'html_document_fromstring', Mock(return_value=None))
+def test_bad_html():
+    bad_html = "<html></html>"
+    eq_(bad_html, quotations.extract_from_html(bad_html))

tests/signature/extraction_test.py

@@ -1,16 +1,16 @@
 # -*- coding: utf-8 -*-
 
 from __future__ import absolute_import
-from .. import *
 
 import os
 
-from talon.signature.learning import dataset
-from talon import signature
-from talon.signature import extraction as e
-from talon.signature import bruteforce
 from six.moves import range
 
+from talon.signature import bruteforce, extraction, extract
+from talon.signature import extraction as e
+from talon.signature.learning import dataset
+from .. import *
+
 
 def test_message_shorter_SIGNATURE_MAX_LINES():
     sender = "bob@foo.bar"
@@ -18,20 +18,25 @@ def test_message_shorter_SIGNATURE_MAX_LINES():
 
 Thanks in advance,
 Bob"""
-    text, extracted_signature = signature.extract(body, sender)
+    text, extracted_signature = extract(body, sender)
     eq_('\n'.join(body.splitlines()[:2]), text)
     eq_('\n'.join(body.splitlines()[-2:]), extracted_signature)
 
 
 def test_messages_longer_SIGNATURE_MAX_LINES():
+    import sys
+    kwargs = {}
+    if sys.version_info > (3, 0):
+        kwargs["encoding"] = "utf8"
+
     for filename in os.listdir(STRIPPED):
         filename = os.path.join(STRIPPED, filename)
         if not filename.endswith('_body'):
             continue
         sender, body = dataset.parse_msg_sender(filename)
-        text, extracted_signature = signature.extract(body, sender)
+        text, extracted_signature = extract(body, sender)
         extracted_signature = extracted_signature or ''
-        with open(filename[:-len('body')] + 'signature') as ms:
+        with open(filename[:-len('body')] + 'signature', **kwargs) as ms:
             msg_signature = ms.read()
             eq_(msg_signature.strip(), extracted_signature.strip())
             stripped_msg = body.strip()[:len(body.strip()) - len(msg_signature)]
@@ -47,7 +52,7 @@ Thanks in advance,
 some text which doesn't seem to be a signature at all
 Bob"""
 
-    text, extracted_signature = signature.extract(body, sender)
+    text, extracted_signature = extract(body, sender)
     eq_('\n'.join(body.splitlines()[:2]), text)
     eq_('\n'.join(body.splitlines()[-3:]), extracted_signature)
 
@@ -60,7 +65,7 @@ Thanks in advance,
 some long text here which doesn't seem to be a signature at all
 Bob"""
 
-    text, extracted_signature = signature.extract(body, sender)
+    text, extracted_signature = extract(body, sender)
     eq_('\n'.join(body.splitlines()[:-1]), text)
     eq_('Bob', extracted_signature)
 
@@ -68,13 +73,13 @@ Bob"""
 
     some *long* text here which doesn't seem to be a signature at all
     """
-    ((body, None), signature.extract(body, "david@example.com"))
+    ((body, None), extract(body, "david@example.com"))
 
 
 def test_basic():
     msg_body = 'Blah\r\n--\r\n\r\nSergey Obukhov'
     eq_(('Blah', '--\r\n\r\nSergey Obukhov'),
-        signature.extract(msg_body, 'Sergey'))
+        extract(msg_body, 'Sergey'))
 
 
 def test_capitalized():
@@ -99,7 +104,7 @@ Doe Inc
 Doe Inc
 555-531-7967"""
 
-    eq_(sig, signature.extract(msg_body, 'Doe')[1])
+    eq_(sig, extract(msg_body, 'Doe')[1])
 
 
 def test_over_2_text_lines_after_signature():
@@ -110,25 +115,25 @@ def test_over_2_text_lines_after_signature():
     2 non signature lines in the end
     It's not signature
     """
-    text, extracted_signature = signature.extract(body, "Bob")
+    text, extracted_signature = extract(body, "Bob")
     eq_(extracted_signature, None)
 
 
 def test_no_signature():
     sender, body = "bob@foo.bar", "Hello"
-    eq_((body, None), signature.extract(body, sender))
+    eq_((body, None), extract(body, sender))
 
 
 def test_handles_unicode():
     sender, body = dataset.parse_msg_sender(UNICODE_MSG)
-    text, extracted_signature = signature.extract(body, sender)
+    text, extracted_signature = extract(body, sender)
 
 
-@patch.object(signature.extraction, 'has_signature')
+@patch.object(extraction, 'has_signature')
 def test_signature_extract_crash(has_signature):
     has_signature.side_effect = Exception('Bam!')
     msg_body = u'Blah\r\n--\r\n\r\nСергей'
-    eq_((msg_body, None), signature.extract(msg_body, 'Сергей'))
+    eq_((msg_body, None), extract(msg_body, 'Сергей'))
 
 
 def test_mark_lines():

tests/text_quotations_test.py

@@ -35,6 +35,19 @@ On 11-Apr-2011, at 6:54 PM, Roman Tkachenko <romant@example.com> wrote:
 
     eq_("Test reply", quotations.extract_from_plain(msg_body))
 
+def test_pattern_on_date_polymail():
+    msg_body = """Test reply
+
+On Tue, Apr 11, 2017 at 10:07 PM John Smith
+
+<
+mailto:John Smith <johnsmith@gmail.com>
+> wrote:
+Test quoted data
+"""
+
+    eq_("Test reply", quotations.extract_from_plain(msg_body))
+
 
 def test_pattern_sent_from_samsung_smb_wrote():
     msg_body = """Test reply
@@ -106,6 +119,38 @@ On 11-Apr-2011, at 6:54 PM, Roman Tkachenko <romant@example.com> sent:
     eq_("Test reply", quotations.extract_from_plain(msg_body))
 
 
+def test_appointment():
+    msg_body = """Response
+
+10/19/2017 @ 9:30 am for physical therapy
+Bla
+1517 4th Avenue Ste 300
+London CA 19129, 555-421-6780
+
+John Doe, FCLS
+Mailgun Inc
+555-941-0697
+
+From: from@example.com [mailto:from@example.com]
+Sent: Wednesday, October 18, 2017 2:05 PM
+To: John Doer - SIU <jd@example.com>
+Subject: RE: Claim # 5551188-1
+
+Text"""
+
+    expected = """Response
+
+10/19/2017 @ 9:30 am for physical therapy
+Bla
+1517 4th Avenue Ste 300
+London CA 19129, 555-421-6780
+
+John Doe, FCLS
+Mailgun Inc
+555-941-0697"""
+    eq_(expected, quotations.extract_from_plain(msg_body))
+
+
 def test_line_starts_with_on():
     msg_body = """Blah-blah-blah
 On blah-blah-blah"""
@@ -142,7 +187,8 @@ def _check_pattern_original_message(original_message_indicator):
 -----{}-----
 
 Test"""
-    eq_('Test reply', quotations.extract_from_plain(msg_body.format(six.text_type(original_message_indicator))))
+    eq_('Test reply', quotations.extract_from_plain(
+        msg_body.format(six.text_type(original_message_indicator))))
 
 def test_english_original_message():
     _check_pattern_original_message('Original Message')
@@ -165,6 +211,17 @@ Test reply"""
     eq_("Test reply", quotations.extract_from_plain(msg_body))
 
 
+def test_android_wrote():
+    msg_body = """Test reply
+
+---- John Smith wrote ----
+
+> quoted
+> text
+"""
+    eq_("Test reply", quotations.extract_from_plain(msg_body))
+
+
 def test_reply_wraps_quotations():
     msg_body = """Test reply
 
@@ -376,6 +433,14 @@ Op 17-feb.-2015, om 13:18 heeft Julius Caesar <pantheon@rome.com> het volgende g
 Small batch beard laboris tempor, non listicle hella Tumblr heirloom.
 """))
 
+def test_vietnamese_from_block():
+    eq_('Hello', quotations.extract_from_plain(
+    u"""Hello
+
+Vào 14:24 8 tháng 6, 2017, Hùng Nguyễn <hungnguyen@xxx.com> đã viết:
+
+> Xin chào
+"""))
 
 def test_quotation_marker_false_positive():
     msg_body = """Visit us now for assistance...
@@ -388,6 +453,7 @@ def test_link_closed_with_quotation_marker_on_new_line():
     msg_body = '''8.45am-1pm
 
 From: somebody@example.com
+Date: Wed, 16 May 2012 00:15:02 -0600
  
 <http://email.example.com/c/dHJhY2tpbmdfY29kZT1mMDdjYzBmNzM1ZjYzMGIxNT
 >  <bob@example.com <mailto:bob@example.com> >
@@ -429,7 +495,9 @@ def test_from_block_starts_with_date():
     msg_body = """Blah
 
 Date: Wed, 16 May 2012 00:15:02 -0600
-To: klizhentas@example.com"""
+To: klizhentas@example.com
+
+"""
     eq_('Blah', quotations.extract_from_plain(msg_body))
 
 
@@ -499,11 +567,12 @@ def test_mark_message_lines():
              # next line should be marked as splitter
              '_____________',
              'From: foo@bar.com',
+             'Date: Wed, 16 May 2012 00:15:02 -0600',
              '',
              '> Hi',
              '',
              'Signature']
-    eq_('tessemet', quotations.mark_message_lines(lines))
+    eq_('tesssemet', quotations.mark_message_lines(lines))
 
     lines = ['Just testing the email reply',
              '',
@@ -696,3 +765,77 @@ def test_standard_replies():
                 "'%(reply)s' != %(stripped)s for %(fn)s" % \
                 {'reply': reply_text, 'stripped': stripped_text,
                  'fn': filename}
+
+
+def test_split_email():
+    msg = """From: Mr. X
+    Date: 24 February 2016
+    To: Mr. Y
+    Subject: Hi
+    Attachments: none
+    Goodbye.
+    From: Mr. Y
+    To: Mr. X
+    Date: 24 February 2016
+    Subject: Hi
+    Attachments: none
+
+    Hello.
+
+        On 24th February 2016 at 09.32am, Conal wrote:
+
+        Hey!
+
+        On Mon, 2016-10-03 at 09:45 -0600, Stangel, Dan wrote:
+        > Mohan,
+        >
+        > We have not yet migrated the systems.
+        >
+        > Dan
+        >
+        > > -----Original Message-----
+        > > Date: Mon, 2 Apr 2012 17:44:22 +0400
+        > > Subject: Test
+        > > From: bob@xxx.mailgun.org
+        > > To: xxx@gmail.com; xxx@hotmail.com; xxx@yahoo.com; xxx@aol.com; xxx@comcast.net; xxx@nyc.rr.com
+        > >
+        > > Hi
+        > >
+        > > > From: bob@xxx.mailgun.org
+        > > > To: xxx@gmail.com; xxx@hotmail.com; xxx@yahoo.com; xxx@aol.com; xxx@comcast.net; xxx@nyc.rr.com
+        > > > Date: Mon, 2 Apr 2012 17:44:22 +0400
+        > > > Subject: Test
+        > > > Hi
+        > > >
+        > >
+        >
+        >
+"""
+    expected_markers = "stttttsttttetesetesmmmmmmsmmmmmmmmmmmmmmmm"
+    markers = quotations.split_emails(msg)
+    eq_(markers, expected_markers)
+
+
+
+def test_feedback_below_left_unparsed():
+    msg_body = """Please enter your feedback below. Thank you.
+
+------------------------------------- Enter Feedback Below -------------------------------------
+
+The user experience was unparallelled. Please continue production. I'm sending payment to ensure
+that this line is intact."""
+
+    parsed = quotations.extract_from_plain(msg_body)
+    eq_(msg_body, parsed.decode('utf8'))
+
+
+def test_appointment():
+    msg_body = """Invitation for an interview:
+
+Date: Wednesday 3, October 2011 
+Time: 7 : 00am 
+Address: 130 Fox St
+
+Please bring in your ID."""
+    parsed = quotations.extract_from_plain(msg_body)
+    eq_(msg_body, parsed.decode('utf8'))

tests/utils_test.py

@@ -1,12 +1,13 @@
 # coding:utf-8
 
 from __future__ import absolute_import
-from . import *
 
-from talon import utils as u
 import cchardet
 import six
 
+from talon import utils as u
+from . import *
+
 
 def test_get_delimiter():
     eq_('\r\n', u.get_delimiter('abc\r\n123'))
@@ -28,7 +29,9 @@ def test_unicode():
 
 def test_detect_encoding():
     eq_('ascii', u.detect_encoding(b'qwe').lower())
-    eq_ ('iso-8859-2', u.detect_encoding(u'Versi\xf3n'.encode('iso-8859-2')).lower())
+    ok_(u.detect_encoding(
+        u'Versi\xf3n'.encode('iso-8859-2')).lower() in [
+            'iso-8859-1', 'iso-8859-2'])
     eq_('utf-8', u.detect_encoding(u'привет'.encode('utf8')).lower())
     # fallback to utf-8
     with patch.object(u.chardet, 'detect') as detect:
@@ -38,7 +41,9 @@ def test_detect_encoding():
 
 def test_quick_detect_encoding():
     eq_('ascii', u.quick_detect_encoding(b'qwe').lower())
-    eq_ ('windows-1252', u.quick_detect_encoding(u'Versi\xf3n'.encode('windows-1252')).lower())
+    ok_(u.quick_detect_encoding(
+        u'Versi\xf3n'.encode('windows-1252')).lower() in [
+            'windows-1252', 'windows-1250'])
     eq_('utf-8', u.quick_detect_encoding(u'привет'.encode('utf8')).lower())
 
 
@@ -107,3 +112,52 @@ font: 13px 'Lucida Grande', Arial, sans-serif;
 <p>TEXT 2 <!-- COMMENT 2 --></p>
 </div>"""
     eq_(b'TEXT 1 \nTEXT 2', u.html_to_text(html))
+
+
+def test_comment_no_parent():
+    s = b'<!-- COMMENT 1 --> no comment'
+    d = u.html_document_fromstring(s)
+    eq_(b"no comment", u.html_tree_to_text(d))
+
+
+@patch.object(u.html5parser, 'fromstring', Mock(side_effect=Exception()))
+def test_html_fromstring_exception():
+    eq_(None, u.html_fromstring("<html></html>"))
+
+
+@patch.object(u, 'html_too_big', Mock())
+@patch.object(u.html5parser, 'fromstring')
+def test_html_fromstring_too_big(fromstring):
+    eq_(None, u.html_fromstring("<html></html>"))
+    assert_false(fromstring.called)
+
+
+@patch.object(u.html5parser, 'document_fromstring')
+def test_html_document_fromstring_exception(document_fromstring):
+    document_fromstring.side_effect = Exception()
+    eq_(None, u.html_document_fromstring("<html></html>"))
+
+
+@patch.object(u, 'html_too_big', Mock())
+@patch.object(u.html5parser, 'document_fromstring')
+def test_html_document_fromstring_too_big(document_fromstring):
+    eq_(None, u.html_document_fromstring("<html></html>"))
+    assert_false(document_fromstring.called)
+
+
+@patch.object(u, 'html_fromstring', Mock(return_value=None))
+def test_bad_html_to_text():
+    bad_html = "one<br>two<br>three"
+    eq_(None, u.html_to_text(bad_html))
+
+
+@patch.object(u, '_MAX_TAGS_COUNT', 3)
+def test_html_too_big():
+    eq_(False, u.html_too_big("<div></div>"))
+    eq_(True, u.html_too_big("<div><span>Hi</span></div>"))
+
+
+@patch.object(u, '_MAX_TAGS_COUNT', 3)
+def test_html_to_text():
+    eq_(b"Hello", u.html_to_text("<div>Hello</div>"))
+    eq_(None, u.html_to_text("<div><span>Hi</span></div>"))