Various changes so most tests pass on Python 3.

1 files changed, 586 insertions, 0 deletions

diff --git a/bs4/tests/test_lxml.py b/bs4/tests/test_lxml.py
new file mode 100644
index 0000000..2f64d31
--- /dev/null
+++ b/bs4/tests/test_lxml.py
@@ -0,0 +1,586 @@
+"""Tests to ensure that the lxml tree builder generates good trees."""
+
+import re
+
+from bs4 import BeautifulSoup
+from bs4.builder import LXMLTreeBuilder, LXMLTreeBuilderForXML
+from bs4.element import Comment, Doctype, SoupStrainer
+from bs4.testing import SoupTest
+
+
+class TestLXMLBuilder(SoupTest):
+    """A smoke test for the LXML tree builder.
+
+    Subclass this to test some other HTML tree builder. Subclasses of
+    this test ensure that all of Beautiful Soup's tree builders
+    generate more or less the same trees.
+
+    It's okay for trees to differ--just override the appropriate test
+    method to demonstrate how one tree builder differs from the LXML
+    builder. But in general, all HTML tree builders should generate
+    trees that make most of these tests pass.
+    """
+
+    def test_bare_string(self):
+        # A bare string is turned into some kind of HTML document or
+        # fragment recognizable as the original string.
+        #
+        # In this case, lxml puts a <p> tag around the bare string.
+        self.assertSoupEquals(
+            "A bare string", "<p>A bare string</p>")
+
+    def test_mixed_case_tags(self):
+        # Mixed-case tags are folded to lowercase.
+        self.assertSoupEquals(
+            "<a><B><Cd><EFG></efg></CD></b></A>",
+            "<a><b><cd><efg></efg></cd></b></a>")
+
+    def test_empty_element(self):
+        # HTML's empty-element tags are recognized as such.
+        self.assertSoupEquals(
+            "<p>A <meta> tag</p>", "<p>A <meta /> tag</p>")
+
+        self.assertSoupEquals(
+            "<p>Foo<br/>bar</p>", "<p>Foo<br />bar</p>")
+
+    def test_empty_tag_thats_not_an_empty_element_tag(self):
+        # A tag that is empty but not an HTML empty-element tag
+        # is not presented as an empty-element tag.
+        self.assertSoupEquals("<p>", "<p></p>")
+
+    def test_comment(self):
+        # Comments are represented as Comment objects.
+        markup = "<p>foo<!--foobar-->baz</p>"
+        self.assertSoupEquals(markup)
+
+        soup = self.soup(markup)
+        comment = soup.find(text="foobar")
+        self.assertEquals(comment.__class__, Comment)
+
+    def test_nested_inline_elements(self):
+        # Inline tags can be nested indefinitely.
+        b_tag = "<b>Inside a B tag</b>"
+        self.assertSoupEquals(b_tag)
+
+        nested_b_tag = "<p>A <i>nested <b>tag</b></i></p>"
+        self.assertSoupEquals(nested_b_tag)
+
+        double_nested_b_tag = "<p>A <a>doubly <i>nested <b>tag</b></i></a></p>"
+        self.assertSoupEquals(nested_b_tag)
+
+    def test_nested_block_level_elements(self):
+        soup = self.soup('<blockquote><p><b>Foo</b></p></blockquote>')
+        blockquote = soup.blockquote
+        self.assertEqual(blockquote.p.b.string, 'Foo')
+        self.assertEqual(blockquote.b.string, 'Foo')
+
+    # This is a <table> tag containing another <table> tag in one of its
+    # cells.
+    TABLE_MARKUP_1 = ('<table id="1">'
+                     '<tr>'
+                     "<td>Here's another table:"
+                     '<table id="2">'
+                     '<tr><td>foo</td></tr>'
+                     '</table></td>')
+
+    def test_correctly_nested_tables(self):
+        markup = ('<table id="1">'
+                  '<tr>'
+                  "<td>Here's another table:"
+                  '<table id="2">'
+                  '<tr><td>foo</td></tr>'
+                  '</table></td>')
+
+        self.assertSoupEquals(
+            markup,
+            '<table id="1"><tr><td>Here\'s another table:'
+            '<table id="2"><tr><td>foo</td></tr></table>'
+            '</td></tr></table>')
+
+        self.assertSoupEquals(
+            "<table><thead><tr><td>Foo</td></tr></thead>"
+            "<tbody><tr><td>Bar</td></tr></tbody>"
+            "<tfoot><tr><td>Baz</td></tr></tfoot></table>")
+
+    def test_collapsed_whitespace(self):
+        """In most tags, whitespace is collapsed."""
+        self.assertSoupEquals("<p>   </p>", "<p> </p>")
+
+    def test_preserved_whitespace_in_pre_and_textarea(self):
+        """In <pre> and <textarea> tags, whitespace is preserved."""
+        self.assertSoupEquals("<pre>   </pre>")
+        self.assertSoupEquals("<textarea> woo  </textarea>")
+
+    def test_single_quote_attribute_values_become_double_quotes(self):
+        self.assertSoupEquals("<foo attr='bar'></foo>",
+                              '<foo attr="bar"></foo>')
+
+    def test_attribute_values_with_nested_quotes_are_left_alone(self):
+        text = """<foo attr='bar "brawls" happen'>a</foo>"""
+        self.assertSoupEquals(text)
+
+    def test_attribute_values_with_double_nested_quotes_get_quoted(self):
+        text = """<foo attr='bar "brawls" happen'>a</foo>"""
+        soup = self.soup(text)
+        soup.foo['attr'] = 'Brawls happen at "Bob\'s Bar"'
+        self.assertSoupEquals(
+            soup.foo.decode(),
+            """<foo attr="Brawls happen at &quot;Bob\'s Bar&quot;">a</foo>""")
+
+    def test_ampersand_in_attribute_value_gets_quoted(self):
+        self.assertSoupEquals('<this is="really messed up & stuff"></this>',
+                              '<this is="really messed up &amp; stuff"></this>')
+
+    def test_literal_in_textarea(self):
+        # Anything inside a <textarea> is supposed to be treated as
+        # the literal value of the field, (XXX citation
+        # needed). html5lib does this correctly. But, lxml does its
+        # best to parse the contents of a <textarea> as HTML.
+        text = '<textarea>Junk like <b> tags and <&<&amp;</textarea>'
+        soup = self.soup(text)
+        self.assertEquals(len(soup.textarea.contents), 2)
+        self.assertEquals(soup.textarea.contents[0], u"Junk like ")
+        self.assertEquals(soup.textarea.contents[1].name, 'b')
+        self.assertEquals(soup.textarea.b.string, u" tags and ")
+
+    def test_literal_in_script(self):
+        # The contents of a <script> tag are treated as a literal string,
+        # even if that string contains HTML.
+        javascript = 'if (i < 2) { alert("<b>foo</b>"); }'
+        soup = self.soup('<script>%s</script>' % javascript)
+        self.assertEquals(soup.script.string, javascript)
+
+    def test_naked_ampersands(self):
+        # Ampersands are left alone.
+        text = "<p>AT&T</p>"
+        soup = self.soup(text)
+        self.assertEquals(soup.p.string, "AT&T")
+
+        # Even if they're in attribute values.
+        invalid_url = '<a href="http://example.org?a=1&b=2;3">foo</a>'
+        soup = self.soup(invalid_url)
+        self.assertEquals(soup.a['href'], "http://example.org?a=1&b=2;3")
+
+    def test_entities_in_strings_converted_during_parsing(self):
+        # Both XML and HTML entities are converted to Unicode characters
+        # during parsing.
+        text = "<p>&lt;&lt;sacr&eacute;&#32;bleu!&gt;&gt;</p>"
+        expected = u"<p><<sacr\N{LATIN SMALL LETTER E WITH ACUTE} bleu!>></p>"
+        self.assertSoupEquals(text, expected)
+
+    def test_smart_quotes_converted_on_the_way_in(self):
+        # Microsoft smart quotes are converted to Unicode characters during
+        # parsing.
+        quote = b"<p>\x91Foo\x92</p>"
+        soup = self.soup(quote)
+        self.assertEquals(
+            soup.p.string,
+            u"\N{LEFT SINGLE QUOTATION MARK}Foo\N{RIGHT SINGLE QUOTATION MARK}")
+
+    def test_non_breaking_spaces_converted_on_the_way_in(self):
+        soup = self.soup("<a>&nbsp;&nbsp;</a>")
+        self.assertEquals(soup.a.string, u"\N{NO-BREAK SPACE}" * 2)
+
+    def test_cdata_where_its_ok(self):
+        # lxml strips CDATA sections, no matter where they occur.
+        markup = "<svg><![CDATA[foobar]]>"
+        self.assertSoupEquals(markup, "<svg></svg>")
+
+    def _test_doctype(self, doctype_fragment):
+        """Run a battery of assertions on a given doctype string."""
+        doctype_str = '<!DOCTYPE %s>' % doctype_fragment
+        markup = doctype_str + '<p>foo</p>'
+        soup = self.soup(markup)
+        doctype = soup.contents[0]
+        self.assertEquals(doctype.__class__, Doctype)
+        self.assertEquals(doctype, doctype_fragment)
+        self.assertEquals(str(soup)[:len(doctype_str)], doctype_str)
+
+        # Make sure that the doctype was correctly associated with the
+        # parse tree and that the rest of the document parsed.
+        self.assertEquals(soup.p.contents[0], 'foo')
+
+    def test_doctype(self):
+        # Test a normal HTML doctype you'll commonly see in a real document.
+        self._test_doctype(
+            'html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"')
+
+    def test_namespaced_system_doctype(self):
+        # Test a namespaced doctype with a system id.
+        self._test_doctype('xsl:stylesheet SYSTEM "htmlent.dtd"')
+
+    def test_namespaced_public_doctype(self):
+        # Test a namespaced doctype with a public id.
+        self._test_doctype('xsl:stylesheet PUBLIC "htmlent.dtd"')
+
+    def test_real_iso_latin_document(self):
+        # Smoke test of interrelated functionality, using an
+        # easy-to-understand document.
+
+        # Here it is in Unicode. Note that it claims to be in ISO-Latin-1.
+        unicode_html = u'<html><head><meta content="text/html; charset=ISO-Latin-1" http-equiv="Content-type" /></head><body><p>Sacr\N{LATIN SMALL LETTER E WITH ACUTE} bleu!</p></body></html>'
+
+        # That's because we're going to encode it into ISO-Latin-1, and use
+        # that to test.
+        iso_latin_html = unicode_html.encode("iso-8859-1")
+
+        # Parse the ISO-Latin-1 HTML.
+        soup = self.soup(iso_latin_html)
+        # Encode it to UTF-8.
+        result = soup.encode("utf-8")
+
+        # What do we expect the result to look like? Well, it would
+        # look like unicode_html, except that the META tag would say
+        # UTF-8 instead of ISO-Latin-1.
+        expected = unicode_html.replace("ISO-Latin-1", "utf-8")
+
+        # And, of course, it would be in UTF-8, not Unicode.
+        expected = expected.encode("utf-8")
+
+        # Ta-da!
+        self.assertEquals(result, expected)
+
+    def test_real_shift_jis_document(self):
+        # Smoke test to make sure the parser can handle a document in
+        # Shift-JIS encoding, without choking.
+        shift_jis_html = (
+            b'<html><head></head><body><pre>'
+            b'\x82\xb1\x82\xea\x82\xcdShift-JIS\x82\xc5\x83R\x81[\x83f'
+            b'\x83B\x83\x93\x83O\x82\xb3\x82\xea\x82\xbd\x93\xfa\x96{\x8c'
+            b'\xea\x82\xcc\x83t\x83@\x83C\x83\x8b\x82\xc5\x82\xb7\x81B'
+            b'</pre></body></html>')
+        unicode_html = shift_jis_html.decode("shift-jis")
+        soup = self.soup(shift_jis_html)
+
+        # Make sure the parse tree is correctly encoded to various
+        # encodings.
+        self.assertEquals(soup.encode("utf-8"), unicode_html.encode("utf-8"))
+        self.assertEquals(soup.encode("euc_jp"), unicode_html.encode("euc_jp"))
+
+    # Tests below this line need work.
+
+    def test_meta_tag_reflects_current_encoding(self):
+        # Here's the <meta> tag saying that a document is
+        # encoded in Shift-JIS.
+        meta_tag = ('<meta content="text/html; charset=x-sjis" '
+                    'http-equiv="Content-type" />')
+
+        # Here's a document incorporating that meta tag.
+        shift_jis_html = (
+            '<html><head>\n%s\n'
+            '<meta http-equiv="Content-language" content="ja" />'
+            '</head><body>Shift-JIS markup goes here.') % meta_tag
+        soup = self.soup(shift_jis_html)
+
+        # Parse the document, and the charset is replaced with a
+        # generic value.
+        parsed_meta = soup.find('meta', {'http-equiv': 'Content-type'})
+        self.assertEquals(parsed_meta['content'],
+                          'text/html; charset=%SOUP-ENCODING%')
+        self.assertEquals(parsed_meta.contains_substitutions, True)
+
+        # For the rest of the story, see TestSubstitutions in
+        # test_tree.py.
+
+    def test_entities_converted_on_the_way_out(self):
+        text = "<p>&lt;&lt;sacr&eacute;&#32;bleu!&gt;&gt;</p>"
+        expected = u"&lt;&lt;sacr\N{LATIN SMALL LETTER E WITH ACUTE} bleu!&gt;&gt;".encode("utf-8")
+        soup = self.soup(text)
+        str = soup.p.string
+        #self.assertEquals(str.encode("utf-8"), expected)
+
+    def test_br_tag_is_empty_element(self):
+        """A <br> tag is designated as an empty-element tag."""
+        soup = self.soup("<br></br>")
+        self.assertTrue(soup.br.is_empty_element)
+        self.assertEquals(str(soup.br), "<br />")
+
+    def test_p_tag_is_not_empty_element(self):
+        """A <p> tag is not designated as an empty-element tag."""
+        soup = self.soup("<p />")
+        self.assertFalse(soup.p.is_empty_element)
+        self.assertEquals(str(soup.p), "<p></p>")
+
+    def test_soupstrainer(self):
+        strainer = SoupStrainer("b")
+        soup = self.soup("A <b>bold</b> <meta /> <i>statement</i>",
+                         parse_only=strainer)
+        self.assertEquals(soup.decode(), "<b>bold</b>")
+
+
+class TestLXMLBuilderInvalidMarkup(SoupTest):
+    """Tests of invalid markup for the LXML tree builder.
+
+    Subclass this to test other builders.
+
+    These are very likely to give different results for different tree
+    builders. It's not required that a tree builder handle invalid
+    markup at all.
+    """
+
+    def test_table_containing_bare_markup(self):
+        # Markup should be in table cells, not directly in the table.
+        self.assertSoupEquals("<table><div>Foo</div></table>")
+
+    def test_incorrectly_nested_table(self):
+        # The second <table> tag is floating in the <tr> tag
+        # rather than being inside a <td>.
+        bad_markup = ('<table id="1">'
+                      '<tr>'
+                      "<td>Here's another table:</td>"
+                      '<table id="2">'
+                      '<tr><td>foo</td></tr>'
+                      '</table></td>')
+
+    def test_unclosed_block_level_elements(self):
+        # Unclosed block-level elements should be closed.
+        self.assertSoupEquals(
+            '<blockquote><p><b>Foo</blockquote><p>Bar',
+            '<blockquote><p><b>Foo</b></p></blockquote><p>Bar</p>')
+
+    def test_fake_self_closing_tag(self):
+        # If a self-closing tag presents as a normal tag, the 'open'
+        # tag is treated as an instance of the self-closing tag and
+        # the 'close' tag is ignored.
+        self.assertSoupEquals(
+            "<item><link>http://foo.com/</link></item>",
+            "<item><link />http://foo.com/</item>")
+
+    def test_boolean_attribute_with_no_value_gets_empty_value(self):
+        soup = self.soup("<table><td nowrap>foo</td></table>")
+        self.assertEquals(soup.table.td['nowrap'], '')
+
+    def test_incorrectly_nested_tables(self):
+        self.assertSoupEquals(
+            '<table><tr><table><tr id="nested">',
+            '<table><tr><table><tr id="nested"></tr></table></tr></table>')
+
+    def test_paragraphs_containing_block_display_elements(self):
+        markup = self.soup("<p>this is the definition:"
+                           "<dl><dt>first case</dt>")
+        # The <p> tag is closed before the <dl> tag begins.
+        self.assertEquals(markup.p.contents, ["this is the definition:"])
+
+    def test_empty_element_tag_with_contents(self):
+        self.assertSoupEquals("<br>foo</br>", "<br />foo")
+
+    def test_doctype_in_body(self):
+        markup = "<p>one<!DOCTYPE foobar>two</p>"
+        self.assertSoupEquals(markup)
+
+    def test_nonsensical_declaration(self):
+        # Declarations that don't make any sense are ignored.
+        self.assertSoupEquals('<! Foo = -8><p>a</p>', "<p>a</p>")
+
+    def test_whitespace_in_doctype(self):
+        # A declaration that has extra whitespace is ignored.
+        self.assertSoupEquals(
+            ('<! DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN">'
+             '<p>foo</p>'),
+            '<p>foo</p>')
+
+    def test_incomplete_declaration(self):
+        # An incomplete declaration will screw up the rest of the document.
+        self.assertSoupEquals('a<!b <p>c', '<p>a</p>')
+
+    def test_cdata_where_it_doesnt_belong(self):
+        #CDATA sections are ignored.
+        markup = "<div><![CDATA[foo]]>"
+        self.assertSoupEquals(markup, "<div></div>")
+
+    def test_attribute_value_never_got_closed(self):
+        markup = '<a href="http://foo.com/</a> and blah and blah'
+        soup = self.soup(markup)
+        self.assertEquals(
+            soup.a['href'], "http://foo.com/</a> and blah and blah")
+
+    def test_attribute_value_was_closed_by_subsequent_tag(self):
+        markup = """<a href="foo</a>, </a><a href="bar">baz</a>"""
+        soup = self.soup(markup)
+        # The string between the first and second quotes was interpreted
+        # as the value of the 'href' attribute.
+        self.assertEquals(soup.a['href'], 'foo</a>, </a><a href=')
+
+        #The string after the second quote (bar"), was treated as an
+        #empty attribute called bar.
+        self.assertEquals(soup.a['bar'], '')
+        self.assertEquals(soup.a.string, "baz")
+
+    def test_unquoted_attribute_value(self):
+        soup = self.soup('<a style={height:21px;}></a>')
+        self.assertEquals(soup.a['style'], '{height:21px;}')
+
+    def test_attribute_value_with_embedded_brackets(self):
+        soup = self.soup('<a b="<a>">')
+        self.assertEquals(soup.a['b'], '<a>')
+
+    def test_nonexistent_entity(self):
+        soup = self.soup("<p>foo&#bar;baz</p>")
+        self.assertEquals(soup.p.string, "foobar;baz")
+
+        # Compare a real entity.
+        soup = self.soup("<p>foo&#100;baz</p>")
+        self.assertEquals(soup.p.string, "foodbaz")
+
+        # Also compare html5lib, which preserves the &# before the
+        # entity name.
+
+    def test_entity_out_of_range(self):
+        # An entity that's out of range will be ignored.
+        soup = self.soup("<p>&#10000000000000;</p>")
+        self.assertEquals(soup.p.string, None)
+
+        soup = self.soup("<p>&#x1000000000000;</p>")
+        self.assertEquals(soup.p.string, None)
+
+
+    def test_entity_was_not_finished(self):
+        soup = self.soup("<p>&lt;Hello&gt")
+        # Compare html5lib, which completes the entity.
+        self.assertEquals(soup.p.string, "<Hello&gt")
+
+    def test_document_ends_with_incomplete_declaration(self):
+        soup = self.soup('<p>a<!b')
+        # This becomes a string 'a'. The incomplete declaration is ignored.
+        # Compare html5lib, which turns it into a comment.
+        self.assertEquals(soup.p.contents, ['a'])
+
+    def test_document_starts_with_bogus_declaration(self):
+        soup = self.soup('<! Foo ><p>a</p>')
+        # The declaration is ignored altogether.
+        self.assertEquals(soup.encode(), b"<html><body><p>a</p></body></html>")
+
+    def test_tag_name_contains_unicode(self):
+        # Unicode characters in tag names are stripped.
+        tag_name = u"<our\N{SNOWMAN}>Joe</our\N{SNOWMAN}>"
+        self.assertSoupEquals("<our>Joe</our>")
+
+class TestLXMLBuilderEncodingConversion(SoupTest):
+    # Test Beautiful Soup's ability to decode and encode from various
+    # encodings.
+
+    def setUp(self):
+        super(TestLXMLBuilderEncodingConversion, self).setUp()
+        self.unicode_data = u"<html><head></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></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.
+        ascii = b"<foo>a</foo>"
+        soup_from_ascii = self.soup(ascii)
+        unicode_output = soup_from_ascii.decode()
+        self.assertTrue(isinstance(unicode_output, unicode))
+        self.assertEquals(unicode_output, self.document_for(ascii.decode()))
+        self.assertEquals(soup_from_ascii.original_encoding, "ascii")
+
+    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.assertEquals(soup_from_unicode.decode(), self.unicode_data)
+        self.assertEquals(soup_from_unicode.foo.string, u'Sacr\xe9 bleu!')
+        self.assertEquals(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.assertEquals(soup_from_utf8.decode(), self.unicode_data)
+        self.assertEquals(soup_from_utf8.foo.string, u'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.assertEquals(soup_from_unicode.encode('utf-8'), self.utf8_data)
+
+    HEBREW_DOCUMENT = b'<html><head><title>Hebrew (ISO 8859-8) in Visual Directionality</title></head><body><h1>Hebrew (ISO 8859-8) in Visual Directionality</h1>\xed\xe5\xec\xf9</body></html>'
+
+    def test_real_hebrew_document(self):
+        # A real-world test to make sure we can convert ISO-8859-9 (a
+        # Hebrew encoding) to UTF-8.
+        soup = self.soup(self.HEBREW_DOCUMENT,
+                         from_encoding="iso-8859-8")
+        self.assertEquals(soup.original_encoding, 'iso-8859-8')
+        self.assertEquals(
+            soup.encode('utf-8'),
+            self.HEBREW_DOCUMENT.decode("iso-8859-8").encode("utf-8"))
+
+
+class TestLXMLXMLBuilder(SoupTest):
+    """Test XML-specific parsing behavior.
+
+    Most of the tests use HTML as an example, since Beautiful Soup is
+    mainly an HTML parser. This test suite is a base for XML-specific
+    tree builders.
+    """
+
+    @property
+    def default_builder(self):
+        return LXMLTreeBuilderForXML()
+
+    def test_mixed_case_tags(self):
+        # Mixed-case tags are *not* folded to lowercase, but the
+        # end tag is always the same case as the start tag.
+        self.assertSoupEquals(
+            "<a><B><Cd><EFG /></CD></b></A>",
+            "<a><B><Cd><EFG /></Cd></B></a>")
+
+
+    def test_cdata_becomes_text(self):
+        # LXML sends CData sections as 'data' events, so we can't
+        # create special CData objects for them. We have to use
+        # NavigableString. I would like to fix this, but it's not a
+        # very high priority.
+        markup = "<foo><![CDATA[iamcdata]]></foo>"
+        soup = self.soup(markup)
+        cdata = soup.foo.contents[0]
+        self.assertEquals(cdata.__class__.__name__, 'NavigableString')
+
+
+    def test_can_handle_invalid_xml(self):
+        self.assertSoupEquals("<a><b>", "<a><b /></a>")
+
+    def test_empty_element_tag(self):
+        soup = self.soup("<p><iamselfclosing /></p>")
+        self.assertTrue(soup.iamselfclosing.is_empty_element)
+
+    def test_self_empty_tag_treated_as_empty_element(self):
+        soup = self.soup("<p><iamclosed></iamclosed></p>")
+        self.assertTrue(soup.iamclosed.is_empty_element)
+
+    def test_self_nonempty_tag_is_not_empty_element(self):
+        soup = self.soup("<p><ihavecontents>contents</ihavecontents></p>")
+        self.assertFalse(soup.ihavecontents.is_empty_element)
+
+    def test_empty_tag_that_stops_being_empty_gets_a_closing_tag(self):
+        soup = self.soup("<bar />")
+        self.assertTrue(soup.bar.is_empty_element)
+        soup.bar.insert(1, "Contents")
+        self.assertFalse(soup.bar.is_empty_element)
+        self.assertEquals(str(soup), self.document_for("<bar>Contents</bar>"))
+
+    def test_designated_empty_element_tag_has_no_closing_tag(self):
+        builder = LXMLTreeBuilderForXML(empty_element_tags=['bar'])
+        soup = BeautifulSoup(builder=builder, markup="<bar></bar>")
+        self.assertTrue(soup.bar.is_empty_element)
+        self.assertEquals(str(soup), self.document_for("<bar />"))
+
+    def test_empty_tag_not_in_empty_element_tag_list_has_closing_tag(self):
+        builder = LXMLTreeBuilderForXML(empty_element_tags=['bar'])
+
+        soup = BeautifulSoup(builder=builder, markup="<foo />")
+        self.assertFalse(soup.foo.is_empty_element)
+        self.assertEquals(str(soup), self.document_for("<foo></foo>"))
+
+    def test_designated_empty_element_tag_does_not_change_parser_behavior(self):
+        # The designated list of empty-element tags only affects how
+        # empty tags are presented. It does not affect how tags are
+        # parsed--that's the parser's job.
+        builder = LXMLTreeBuilderForXML(empty_element_tags=['bar'])
+        soup = BeautifulSoup(builder=builder, markup="<bar>contents</bar>")
+        self.assertEquals(str(soup), self.document_for("<bar>contents</bar>"))