diff env/lib/python3.7/site-packages/bs4/tests/test_soup.py @ 0:26e78fe6e8c4 draft

"planemo upload commit c699937486c35866861690329de38ec1a5d9f783"
author shellac
date Sat, 02 May 2020 07:14:21 -0400
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.7/site-packages/bs4/tests/test_soup.py	Sat May 02 07:14:21 2020 -0400
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+# -*- coding: utf-8 -*-
+"""Tests of Beautiful Soup as a whole."""
+
+from pdb import set_trace
+import logging
+import unittest
+import sys
+import tempfile
+
+from bs4 import (
+    BeautifulSoup,
+    BeautifulStoneSoup,
+)
+from bs4.builder import (
+    TreeBuilder,
+    ParserRejectedMarkup,
+)
+from bs4.element import (
+    CharsetMetaAttributeValue,
+    Comment,
+    ContentMetaAttributeValue,
+    SoupStrainer,
+    NamespacedAttribute,
+    Tag,
+    NavigableString,
+    )
+
+import bs4.dammit
+from bs4.dammit import (
+    EntitySubstitution,
+    UnicodeDammit,
+    EncodingDetector,
+)
+from bs4.testing import (
+    default_builder,
+    SoupTest,
+    skipIf,
+)
+import warnings
+
+try:
+    from bs4.builder import LXMLTreeBuilder, LXMLTreeBuilderForXML
+    LXML_PRESENT = True
+except ImportError as e:
+    LXML_PRESENT = False
+
+PYTHON_3_PRE_3_2 = (sys.version_info[0] == 3 and sys.version_info < (3,2))
+
+class TestConstructor(SoupTest):
+
+    def test_short_unicode_input(self):
+        data = "<h1>éé</h1>"
+        soup = self.soup(data)
+        self.assertEqual("éé", soup.h1.string)
+
+    def test_embedded_null(self):
+        data = "<h1>foo\0bar</h1>"
+        soup = self.soup(data)
+        self.assertEqual("foo\0bar", soup.h1.string)
+
+    def test_exclude_encodings(self):
+        utf8_data = "Räksmörgås".encode("utf-8")
+        soup = self.soup(utf8_data, exclude_encodings=["utf-8"])
+        self.assertEqual("windows-1252", soup.original_encoding)
+
+    def test_custom_builder_class(self):
+        # Verify that you can pass in a custom Builder class and
+        # it'll be instantiated with the appropriate keyword arguments.
+        class Mock(object):
+            def __init__(self, **kwargs):
+                self.called_with = kwargs
+                self.is_xml = True
+                self.store_line_numbers = False
+                self.cdata_list_attributes = []
+                self.preserve_whitespace_tags = []
+                self.string_containers = {}
+            def initialize_soup(self, soup):
+                pass
+            def feed(self, markup):
+                self.fed = markup
+            def reset(self):
+                pass
+            def ignore(self, ignore):
+                pass
+            set_up_substitutions = can_be_empty_element = ignore
+            def prepare_markup(self, *args, **kwargs):
+                yield "prepared markup", "original encoding", "declared encoding", "contains replacement characters"
+                
+        kwargs = dict(
+            var="value",
+            # This is a deprecated BS3-era keyword argument, which
+            # will be stripped out.
+            convertEntities=True,
+        )
+        with warnings.catch_warnings(record=True):
+            soup = BeautifulSoup('', builder=Mock, **kwargs)
+        assert isinstance(soup.builder, Mock)
+        self.assertEqual(dict(var="value"), soup.builder.called_with)
+        self.assertEqual("prepared markup", soup.builder.fed)
+        
+        # You can also instantiate the TreeBuilder yourself. In this
+        # case, that specific object is used and any keyword arguments
+        # to the BeautifulSoup constructor are ignored.
+        builder = Mock(**kwargs)
+        with warnings.catch_warnings(record=True) as w:
+            soup = BeautifulSoup(
+                '', builder=builder, ignored_value=True,
+            )
+        msg = str(w[0].message)
+        assert msg.startswith("Keyword arguments to the BeautifulSoup constructor will be ignored.")
+        self.assertEqual(builder, soup.builder)
+        self.assertEqual(kwargs, builder.called_with)
+
+    def test_parser_markup_rejection(self):
+        # If markup is completely rejected by the parser, an
+        # explanatory ParserRejectedMarkup exception is raised.
+        class Mock(TreeBuilder):
+            def feed(self, *args, **kwargs):
+                raise ParserRejectedMarkup("Nope.")
+
+        def prepare_markup(self, *args, **kwargs):
+            # We're going to try two different ways of preparing this markup,
+            # but feed() will reject both of them.
+            yield markup, None, None, False
+            yield markup, None, None, False
+            
+        import re
+        self.assertRaisesRegex(
+            ParserRejectedMarkup,
+            "The markup you provided was rejected by the parser. Trying a different parser or a different encoding may help.",
+            BeautifulSoup, '', builder=Mock,
+        )
+        
+    def test_cdata_list_attributes(self):
+        # Most attribute values are represented as scalars, but the
+        # HTML standard says that some attributes, like 'class' have
+        # space-separated lists as values.
+        markup = '<a id=" an id " class=" a class "></a>'
+        soup = self.soup(markup)
+
+        # Note that the spaces are stripped for 'class' but not for 'id'.
+        a = soup.a
+        self.assertEqual(" an id ", a['id'])
+        self.assertEqual(["a", "class"], a['class'])
+
+        # TreeBuilder takes an argument called 'mutli_valued_attributes'  which lets
+        # you customize or disable this. As always, you can customize the TreeBuilder
+        # by passing in a keyword argument to the BeautifulSoup constructor.
+        soup = self.soup(markup, builder=default_builder, multi_valued_attributes=None)
+        self.assertEqual(" a class ", soup.a['class'])
+
+        # Here are two ways of saying that `id` is a multi-valued
+        # attribute in this context, but 'class' is not.
+        for switcheroo in ({'*': 'id'}, {'a': 'id'}):
+            with warnings.catch_warnings(record=True) as w:
+                # This will create a warning about not explicitly
+                # specifying a parser, but we'll ignore it.
+                soup = self.soup(markup, builder=None, multi_valued_attributes=switcheroo)
+            a = soup.a
+            self.assertEqual(["an", "id"], a['id'])
+            self.assertEqual(" a class ", a['class'])
+
+    def test_replacement_classes(self):
+        # Test the ability to pass in replacements for element classes
+        # which will be used when building the tree.
+        class TagPlus(Tag):
+            pass
+
+        class StringPlus(NavigableString):
+            pass
+
+        class CommentPlus(Comment):
+            pass
+        
+        soup = self.soup(
+            "<a><b>foo</b>bar</a><!--whee-->",
+            element_classes = {
+                Tag: TagPlus,
+                NavigableString: StringPlus,
+                Comment: CommentPlus,
+            }
+        )
+
+        # The tree was built with TagPlus, StringPlus, and CommentPlus objects,
+        # rather than Tag, String, and Comment objects.
+        assert all(
+            isinstance(x, (TagPlus, StringPlus, CommentPlus))
+            for x in soup.recursiveChildGenerator()
+        )
+
+    def test_alternate_string_containers(self):
+        # Test the ability to customize the string containers for
+        # different types of tags.
+        class PString(NavigableString):
+            pass
+
+        class BString(NavigableString):
+            pass
+
+        soup = self.soup(
+            "<div>Hello.<p>Here is <b>some <i>bolded</i></b> text",
+            string_containers = {
+                'b': BString,
+                'p': PString,
+            }
+        )
+
+        # The string before the <p> tag is a regular NavigableString.
+        assert isinstance(soup.div.contents[0], NavigableString)
+        
+        # The string inside the <p> tag, but not inside the <i> tag,
+        # is a PString.
+        assert isinstance(soup.p.contents[0], PString)
+
+        # Every string inside the <b> tag is a BString, even the one that
+        # was also inside an <i> tag.
+        for s in soup.b.strings:
+            assert isinstance(s, BString)
+
+        # Now that parsing was complete, the string_container_stack
+        # (where this information was kept) has been cleared out.
+        self.assertEqual([], soup.string_container_stack)
+
+
+class TestWarnings(SoupTest):
+
+    def _no_parser_specified(self, s, is_there=True):
+        v = s.startswith(BeautifulSoup.NO_PARSER_SPECIFIED_WARNING[:80])
+        self.assertTrue(v)
+
+    def test_warning_if_no_parser_specified(self):
+        with warnings.catch_warnings(record=True) as w:
+            soup = self.soup("<a><b></b></a>")
+        msg = str(w[0].message)
+        self._assert_no_parser_specified(msg)
+
+    def test_warning_if_parser_specified_too_vague(self):
+        with warnings.catch_warnings(record=True) as w:
+            soup = self.soup("<a><b></b></a>", "html")
+        msg = str(w[0].message)
+        self._assert_no_parser_specified(msg)
+
+    def test_no_warning_if_explicit_parser_specified(self):
+        with warnings.catch_warnings(record=True) as w:
+            soup = self.soup("<a><b></b></a>", "html.parser")
+        self.assertEqual([], w)
+
+    def test_parseOnlyThese_renamed_to_parse_only(self):
+        with warnings.catch_warnings(record=True) as w:
+            soup = self.soup("<a><b></b></a>", parseOnlyThese=SoupStrainer("b"))
+        msg = str(w[0].message)
+        self.assertTrue("parseOnlyThese" in msg)
+        self.assertTrue("parse_only" in msg)
+        self.assertEqual(b"<b></b>", soup.encode())
+
+    def test_fromEncoding_renamed_to_from_encoding(self):
+        with warnings.catch_warnings(record=True) as w:
+            utf8 = b"\xc3\xa9"
+            soup = self.soup(utf8, fromEncoding="utf8")
+        msg = str(w[0].message)
+        self.assertTrue("fromEncoding" in msg)
+        self.assertTrue("from_encoding" in msg)
+        self.assertEqual("utf8", soup.original_encoding)
+
+    def test_unrecognized_keyword_argument(self):
+        self.assertRaises(
+            TypeError, self.soup, "<a>", no_such_argument=True)
+
+class TestWarnings(SoupTest):
+
+    def test_disk_file_warning(self):
+        filehandle = tempfile.NamedTemporaryFile()
+        filename = filehandle.name
+        try:
+            with warnings.catch_warnings(record=True) as w:
+                soup = self.soup(filename)
+            msg = str(w[0].message)
+            self.assertTrue("looks like a filename" in msg)
+        finally:
+            filehandle.close()
+
+        # The file no longer exists, so Beautiful Soup will no longer issue the warning.
+        with warnings.catch_warnings(record=True) as w:
+            soup = self.soup(filename)
+        self.assertEqual(0, len(w))
+
+    def test_url_warning_with_bytes_url(self):
+        with warnings.catch_warnings(record=True) as warning_list:
+            soup = self.soup(b"http://www.crummybytes.com/")
+        # Be aware this isn't the only warning that can be raised during
+        # execution..
+        self.assertTrue(any("looks like a URL" in str(w.message) 
+            for w in warning_list))
+
+    def test_url_warning_with_unicode_url(self):
+        with warnings.catch_warnings(record=True) as warning_list:
+            # note - this url must differ from the bytes one otherwise
+            # python's warnings system swallows the second warning
+            soup = self.soup("http://www.crummyunicode.com/")
+        self.assertTrue(any("looks like a URL" in str(w.message) 
+            for w in warning_list))
+
+    def test_url_warning_with_bytes_and_space(self):
+        with warnings.catch_warnings(record=True) as warning_list:
+            soup = self.soup(b"http://www.crummybytes.com/ is great")
+        self.assertFalse(any("looks like a URL" in str(w.message) 
+            for w in warning_list))
+
+    def test_url_warning_with_unicode_and_space(self):
+        with warnings.catch_warnings(record=True) as warning_list:
+            soup = self.soup("http://www.crummyuncode.com/ is great")
+        self.assertFalse(any("looks like a URL" in str(w.message) 
+            for w in warning_list))
+
+
+class TestSelectiveParsing(SoupTest):
+
+    def test_parse_with_soupstrainer(self):
+        markup = "No<b>Yes</b><a>No<b>Yes <c>Yes</c></b>"
+        strainer = SoupStrainer("b")
+        soup = self.soup(markup, parse_only=strainer)
+        self.assertEqual(soup.encode(), b"<b>Yes</b><b>Yes <c>Yes</c></b>")
+
+
+class TestEntitySubstitution(unittest.TestCase):
+    """Standalone tests of the EntitySubstitution class."""
+    def setUp(self):
+        self.sub = EntitySubstitution
+
+    def test_simple_html_substitution(self):
+        # Unicode characters corresponding to named HTML entites
+        # are substituted, and no others.
+        s = "foo\u2200\N{SNOWMAN}\u00f5bar"
+        self.assertEqual(self.sub.substitute_html(s),
+                          "foo&forall;\N{SNOWMAN}&otilde;bar")
+
+    def test_smart_quote_substitution(self):
+        # MS smart quotes are a common source of frustration, so we
+        # give them a special test.
+        quotes = b"\x91\x92foo\x93\x94"
+        dammit = UnicodeDammit(quotes)
+        self.assertEqual(self.sub.substitute_html(dammit.markup),
+                          "&lsquo;&rsquo;foo&ldquo;&rdquo;")
+
+    def test_xml_converstion_includes_no_quotes_if_make_quoted_attribute_is_false(self):
+        s = 'Welcome to "my bar"'
+        self.assertEqual(self.sub.substitute_xml(s, False), s)
+
+    def test_xml_attribute_quoting_normally_uses_double_quotes(self):
+        self.assertEqual(self.sub.substitute_xml("Welcome", True),
+                          '"Welcome"')
+        self.assertEqual(self.sub.substitute_xml("Bob's Bar", True),
+                          '"Bob\'s Bar"')
+
+    def test_xml_attribute_quoting_uses_single_quotes_when_value_contains_double_quotes(self):
+        s = 'Welcome to "my bar"'
+        self.assertEqual(self.sub.substitute_xml(s, True),
+                          "'Welcome to \"my bar\"'")
+
+    def test_xml_attribute_quoting_escapes_single_quotes_when_value_contains_both_single_and_double_quotes(self):
+        s = 'Welcome to "Bob\'s Bar"'
+        self.assertEqual(
+            self.sub.substitute_xml(s, True),
+            '"Welcome to &quot;Bob\'s Bar&quot;"')
+
+    def test_xml_quotes_arent_escaped_when_value_is_not_being_quoted(self):
+        quoted = 'Welcome to "Bob\'s Bar"'
+        self.assertEqual(self.sub.substitute_xml(quoted), quoted)
+
+    def test_xml_quoting_handles_angle_brackets(self):
+        self.assertEqual(
+            self.sub.substitute_xml("foo<bar>"),
+            "foo&lt;bar&gt;")
+
+    def test_xml_quoting_handles_ampersands(self):
+        self.assertEqual(self.sub.substitute_xml("AT&T"), "AT&amp;T")
+
+    def test_xml_quoting_including_ampersands_when_they_are_part_of_an_entity(self):
+        self.assertEqual(
+            self.sub.substitute_xml("&Aacute;T&T"),
+            "&amp;Aacute;T&amp;T")
+
+    def test_xml_quoting_ignoring_ampersands_when_they_are_part_of_an_entity(self):
+        self.assertEqual(
+            self.sub.substitute_xml_containing_entities("&Aacute;T&T"),
+            "&Aacute;T&amp;T")
+       
+    def test_quotes_not_html_substituted(self):
+        """There's no need to do this except inside attribute values."""
+        text = 'Bob\'s "bar"'
+        self.assertEqual(self.sub.substitute_html(text), text)
+
+
+class TestEncodingConversion(SoupTest):
+    # Test Beautiful Soup's ability to decode and encode from various
+    # encodings.
+
+    def setUp(self):
+        super(TestEncodingConversion, self).setUp()
+        self.unicode_data = '<html><head><meta charset="utf-8"/></head><body><foo>Sacr\N{LATIN SMALL LETTER E WITH ACUTE} bleu!</foo></body></html>'
+        self.utf8_data = self.unicode_data.encode("utf-8")
+        # Just so you know what it looks like.
+        self.assertEqual(
+            self.utf8_data,
+            b'<html><head><meta charset="utf-8"/></head><body><foo>Sacr\xc3\xa9 bleu!</foo></body></html>')
+
+    def test_ascii_in_unicode_out(self):
+        # ASCII input is converted to Unicode. The original_encoding
+        # attribute is set to 'utf-8', a superset of ASCII.
+        chardet = bs4.dammit.chardet_dammit
+        logging.disable(logging.WARNING)
+        try:
+            def noop(str):
+                return None
+            # Disable chardet, which will realize that the ASCII is ASCII.
+            bs4.dammit.chardet_dammit = noop
+            ascii = b"<foo>a</foo>"
+            soup_from_ascii = self.soup(ascii)
+            unicode_output = soup_from_ascii.decode()
+            self.assertTrue(isinstance(unicode_output, str))
+            self.assertEqual(unicode_output, self.document_for(ascii.decode()))
+            self.assertEqual(soup_from_ascii.original_encoding.lower(), "utf-8")
+        finally:
+            logging.disable(logging.NOTSET)
+            bs4.dammit.chardet_dammit = chardet
+
+    def test_unicode_in_unicode_out(self):
+        # Unicode input is left alone. The original_encoding attribute
+        # is not set.
+        soup_from_unicode = self.soup(self.unicode_data)
+        self.assertEqual(soup_from_unicode.decode(), self.unicode_data)
+        self.assertEqual(soup_from_unicode.foo.string, 'Sacr\xe9 bleu!')
+        self.assertEqual(soup_from_unicode.original_encoding, None)
+
+    def test_utf8_in_unicode_out(self):
+        # UTF-8 input is converted to Unicode. The original_encoding
+        # attribute is set.
+        soup_from_utf8 = self.soup(self.utf8_data)
+        self.assertEqual(soup_from_utf8.decode(), self.unicode_data)
+        self.assertEqual(soup_from_utf8.foo.string, 'Sacr\xe9 bleu!')
+
+    def test_utf8_out(self):
+        # The internal data structures can be encoded as UTF-8.
+        soup_from_unicode = self.soup(self.unicode_data)
+        self.assertEqual(soup_from_unicode.encode('utf-8'), self.utf8_data)
+
+    @skipIf(
+        PYTHON_3_PRE_3_2,
+        "Bad HTMLParser detected; skipping test of non-ASCII characters in attribute name.")
+    def test_attribute_name_containing_unicode_characters(self):
+        markup = '<div><a \N{SNOWMAN}="snowman"></a></div>'
+        self.assertEqual(self.soup(markup).div.encode("utf8"), markup.encode("utf8"))
+
+class TestUnicodeDammit(unittest.TestCase):
+    """Standalone tests of UnicodeDammit."""
+
+    def test_unicode_input(self):
+        markup = "I'm already Unicode! \N{SNOWMAN}"
+        dammit = UnicodeDammit(markup)
+        self.assertEqual(dammit.unicode_markup, markup)
+
+    def test_smart_quotes_to_unicode(self):
+        markup = b"<foo>\x91\x92\x93\x94</foo>"
+        dammit = UnicodeDammit(markup)
+        self.assertEqual(
+            dammit.unicode_markup, "<foo>\u2018\u2019\u201c\u201d</foo>")
+
+    def test_smart_quotes_to_xml_entities(self):
+        markup = b"<foo>\x91\x92\x93\x94</foo>"
+        dammit = UnicodeDammit(markup, smart_quotes_to="xml")
+        self.assertEqual(
+            dammit.unicode_markup, "<foo>&#x2018;&#x2019;&#x201C;&#x201D;</foo>")
+
+    def test_smart_quotes_to_html_entities(self):
+        markup = b"<foo>\x91\x92\x93\x94</foo>"
+        dammit = UnicodeDammit(markup, smart_quotes_to="html")
+        self.assertEqual(
+            dammit.unicode_markup, "<foo>&lsquo;&rsquo;&ldquo;&rdquo;</foo>")
+
+    def test_smart_quotes_to_ascii(self):
+        markup = b"<foo>\x91\x92\x93\x94</foo>"
+        dammit = UnicodeDammit(markup, smart_quotes_to="ascii")
+        self.assertEqual(
+            dammit.unicode_markup, """<foo>''""</foo>""")
+
+    def test_detect_utf8(self):
+        utf8 = b"Sacr\xc3\xa9 bleu! \xe2\x98\x83"
+        dammit = UnicodeDammit(utf8)
+        self.assertEqual(dammit.original_encoding.lower(), 'utf-8')
+        self.assertEqual(dammit.unicode_markup, 'Sacr\xe9 bleu! \N{SNOWMAN}')
+
+
+    def test_convert_hebrew(self):
+        hebrew = b"\xed\xe5\xec\xf9"
+        dammit = UnicodeDammit(hebrew, ["iso-8859-8"])
+        self.assertEqual(dammit.original_encoding.lower(), 'iso-8859-8')
+        self.assertEqual(dammit.unicode_markup, '\u05dd\u05d5\u05dc\u05e9')
+
+    def test_dont_see_smart_quotes_where_there_are_none(self):
+        utf_8 = b"\343\202\261\343\203\274\343\202\277\343\202\244 Watch"
+        dammit = UnicodeDammit(utf_8)
+        self.assertEqual(dammit.original_encoding.lower(), 'utf-8')
+        self.assertEqual(dammit.unicode_markup.encode("utf-8"), utf_8)
+
+    def test_ignore_inappropriate_codecs(self):
+        utf8_data = "Räksmörgås".encode("utf-8")
+        dammit = UnicodeDammit(utf8_data, ["iso-8859-8"])
+        self.assertEqual(dammit.original_encoding.lower(), 'utf-8')
+
+    def test_ignore_invalid_codecs(self):
+        utf8_data = "Räksmörgås".encode("utf-8")
+        for bad_encoding in ['.utf8', '...', 'utF---16.!']:
+            dammit = UnicodeDammit(utf8_data, [bad_encoding])
+            self.assertEqual(dammit.original_encoding.lower(), 'utf-8')
+
+    def test_exclude_encodings(self):
+        # This is UTF-8.
+        utf8_data = "Räksmörgås".encode("utf-8")
+
+        # But if we exclude UTF-8 from consideration, the guess is
+        # Windows-1252.
+        dammit = UnicodeDammit(utf8_data, exclude_encodings=["utf-8"])
+        self.assertEqual(dammit.original_encoding.lower(), 'windows-1252')
+
+        # And if we exclude that, there is no valid guess at all.
+        dammit = UnicodeDammit(
+            utf8_data, exclude_encodings=["utf-8", "windows-1252"])
+        self.assertEqual(dammit.original_encoding, None)
+
+    def test_encoding_detector_replaces_junk_in_encoding_name_with_replacement_character(self):
+        detected = EncodingDetector(
+            b'<?xml version="1.0" encoding="UTF-\xdb" ?>')
+        encodings = list(detected.encodings)
+        assert 'utf-\N{REPLACEMENT CHARACTER}' in encodings
+
+    def test_detect_html5_style_meta_tag(self):
+
+        for data in (
+            b'<html><meta charset="euc-jp" /></html>',
+            b"<html><meta charset='euc-jp' /></html>",
+            b"<html><meta charset=euc-jp /></html>",
+            b"<html><meta charset=euc-jp/></html>"):
+            dammit = UnicodeDammit(data, is_html=True)
+            self.assertEqual(
+                "euc-jp", dammit.original_encoding)
+
+    def test_last_ditch_entity_replacement(self):
+        # This is a UTF-8 document that contains bytestrings
+        # completely incompatible with UTF-8 (ie. encoded with some other
+        # encoding).
+        #
+        # Since there is no consistent encoding for the document,
+        # Unicode, Dammit will eventually encode the document as UTF-8
+        # and encode the incompatible characters as REPLACEMENT
+        # CHARACTER.
+        #
+        # If chardet is installed, it will detect that the document
+        # can be converted into ISO-8859-1 without errors. This happens
+        # to be the wrong encoding, but it is a consistent encoding, so the
+        # code we're testing here won't run.
+        #
+        # So we temporarily disable chardet if it's present.
+        doc = b"""\357\273\277<?xml version="1.0" encoding="UTF-8"?>
+<html><b>\330\250\330\252\330\261</b>
+<i>\310\322\321\220\312\321\355\344</i></html>"""
+        chardet = bs4.dammit.chardet_dammit
+        logging.disable(logging.WARNING)
+        try:
+            def noop(str):
+                return None
+            bs4.dammit.chardet_dammit = noop
+            dammit = UnicodeDammit(doc)
+            self.assertEqual(True, dammit.contains_replacement_characters)
+            self.assertTrue("\ufffd" in dammit.unicode_markup)
+
+            soup = BeautifulSoup(doc, "html.parser")
+            self.assertTrue(soup.contains_replacement_characters)
+        finally:
+            logging.disable(logging.NOTSET)
+            bs4.dammit.chardet_dammit = chardet
+
+    def test_byte_order_mark_removed(self):
+        # A document written in UTF-16LE will have its byte order marker stripped.
+        data = b'\xff\xfe<\x00a\x00>\x00\xe1\x00\xe9\x00<\x00/\x00a\x00>\x00'
+        dammit = UnicodeDammit(data)
+        self.assertEqual("<a>áé</a>", dammit.unicode_markup)
+        self.assertEqual("utf-16le", dammit.original_encoding)
+
+    def test_detwingle(self):
+        # Here's a UTF8 document.
+        utf8 = ("\N{SNOWMAN}" * 3).encode("utf8")
+
+        # Here's a Windows-1252 document.
+        windows_1252 = (
+            "\N{LEFT DOUBLE QUOTATION MARK}Hi, I like Windows!"
+            "\N{RIGHT DOUBLE QUOTATION MARK}").encode("windows_1252")
+
+        # Through some unholy alchemy, they've been stuck together.
+        doc = utf8 + windows_1252 + utf8
+
+        # The document can't be turned into UTF-8:
+        self.assertRaises(UnicodeDecodeError, doc.decode, "utf8")
+
+        # Unicode, Dammit thinks the whole document is Windows-1252,
+        # and decodes it into "☃☃☃“Hi, I like Windows!”☃☃☃"
+
+        # But if we run it through fix_embedded_windows_1252, it's fixed:
+
+        fixed = UnicodeDammit.detwingle(doc)
+        self.assertEqual(
+            "☃☃☃“Hi, I like Windows!”☃☃☃", fixed.decode("utf8"))
+
+    def test_detwingle_ignores_multibyte_characters(self):
+        # Each of these characters has a UTF-8 representation ending
+        # in \x93. \x93 is a smart quote if interpreted as
+        # Windows-1252. But our code knows to skip over multibyte
+        # UTF-8 characters, so they'll survive the process unscathed.
+        for tricky_unicode_char in (
+            "\N{LATIN SMALL LIGATURE OE}", # 2-byte char '\xc5\x93'
+            "\N{LATIN SUBSCRIPT SMALL LETTER X}", # 3-byte char '\xe2\x82\x93'
+            "\xf0\x90\x90\x93", # This is a CJK character, not sure which one.
+            ):
+            input = tricky_unicode_char.encode("utf8")
+            self.assertTrue(input.endswith(b'\x93'))
+            output = UnicodeDammit.detwingle(input)
+            self.assertEqual(output, input)
+
+    def test_find_declared_encoding(self):
+        # Test our ability to find a declared encoding inside an
+        # XML or HTML document.
+        #
+        # Even if the document comes in as Unicode, it may be
+        # interesting to know what encoding was claimed
+        # originally.
+
+        html_unicode = '<html><head><meta charset="utf-8"></head></html>'
+        html_bytes = html_unicode.encode("ascii")
+
+        xml_unicode= '<?xml version="1.0" encoding="ISO-8859-1" ?>'
+        xml_bytes = xml_unicode.encode("ascii")
+
+        m = EncodingDetector.find_declared_encoding
+        self.assertEqual(None, m(html_unicode, is_html=False))
+        self.assertEqual("utf-8", m(html_unicode, is_html=True))
+        self.assertEqual("utf-8", m(html_bytes, is_html=True))
+
+        self.assertEqual("iso-8859-1", m(xml_unicode))
+        self.assertEqual("iso-8859-1", m(xml_bytes))
+
+        # Normally, only the first few kilobytes of a document are checked for
+        # an encoding.
+        spacer = b' ' * 5000
+        self.assertEqual(None, m(spacer + html_bytes))
+        self.assertEqual(None, m(spacer + xml_bytes))
+
+        # But you can tell find_declared_encoding to search an entire
+        # HTML document.
+        self.assertEqual(
+            "utf-8",
+            m(spacer + html_bytes, is_html=True, search_entire_document=True)
+        )
+
+        # The XML encoding declaration has to be the very first thing
+        # in the document. We'll allow whitespace before the document
+        # starts, but nothing else.
+        self.assertEqual(
+            "iso-8859-1",
+            m(xml_bytes, search_entire_document=True)
+        )
+        self.assertEqual(
+            None, m(b'a' + xml_bytes, search_entire_document=True)
+        )
+            
+class TestNamedspacedAttribute(SoupTest):
+
+    def test_name_may_be_none_or_missing(self):
+        a = NamespacedAttribute("xmlns", None)
+        self.assertEqual(a, "xmlns")
+
+        a = NamespacedAttribute("xmlns")
+        self.assertEqual(a, "xmlns")
+        
+    def test_attribute_is_equivalent_to_colon_separated_string(self):
+        a = NamespacedAttribute("a", "b")
+        self.assertEqual("a:b", a)
+
+    def test_attributes_are_equivalent_if_prefix_and_name_identical(self):
+        a = NamespacedAttribute("a", "b", "c")
+        b = NamespacedAttribute("a", "b", "c")
+        self.assertEqual(a, b)
+
+        # The actual namespace is not considered.
+        c = NamespacedAttribute("a", "b", None)
+        self.assertEqual(a, c)
+
+        # But name and prefix are important.
+        d = NamespacedAttribute("a", "z", "c")
+        self.assertNotEqual(a, d)
+
+        e = NamespacedAttribute("z", "b", "c")
+        self.assertNotEqual(a, e)
+
+
+class TestAttributeValueWithCharsetSubstitution(unittest.TestCase):
+
+    def test_content_meta_attribute_value(self):
+        value = CharsetMetaAttributeValue("euc-jp")
+        self.assertEqual("euc-jp", value)
+        self.assertEqual("euc-jp", value.original_value)
+        self.assertEqual("utf8", value.encode("utf8"))
+
+
+    def test_content_meta_attribute_value(self):
+        value = ContentMetaAttributeValue("text/html; charset=euc-jp")
+        self.assertEqual("text/html; charset=euc-jp", value)
+        self.assertEqual("text/html; charset=euc-jp", value.original_value)
+        self.assertEqual("text/html; charset=utf8", value.encode("utf8"))