lib/bs4/tests/test_tree.py

# -*- coding: utf-8 -*-
"""Tests for Beautiful Soup's tree traversal methods.

The tree traversal methods are the main advantage of using Beautiful
Soup over just using a parser.

Different parsers will build different Beautiful Soup trees given the
same markup, but all Beautiful Soup trees can be traversed with the
methods tested here.
"""

import copy
import pickle
import re
import warnings
from bs4 import BeautifulSoup
from bs4.builder import (
    builder_registry,
    HTMLParserTreeBuilder,
)
from bs4.element import (
    CData,
    Comment,
    Doctype,
    NavigableString,
    SoupStrainer,
    Tag,
)
from bs4.testing import (
    SoupTest,
    skipIf,
)

XML_BUILDER_PRESENT = (builder_registry.lookup("xml") is not None)
LXML_PRESENT = (builder_registry.lookup("lxml") is not None)

class TreeTest(SoupTest):

    def assertSelects(self, tags, should_match):
        """Make sure that the given tags have the correct text.

        This is used in tests that define a bunch of tags, each
        containing a single string, and then select certain strings by
        some mechanism.
        """
        self.assertEqual([tag.string for tag in tags], should_match)

    def assertSelectsIDs(self, tags, should_match):
        """Make sure that the given tags have the correct IDs.

        This is used in tests that define a bunch of tags, each
        containing a single string, and then select certain strings by
        some mechanism.
        """
        self.assertEqual([tag['id'] for tag in tags], should_match)


class TestFind(TreeTest):
    """Basic tests of the find() method.

    find() just calls find_all() with limit=1, so it's not tested all
    that thouroughly here.
    """

    def test_find_tag(self):
        soup = self.soup("<a>1</a><b>2</b><a>3</a><b>4</b>")
        self.assertEqual(soup.find("b").string, "2")

    def test_unicode_text_find(self):
        soup = self.soup(u'<h1>Räksmörgås</h1>')
        self.assertEqual(soup.find(text=u'Räksmörgås'), u'Räksmörgås')

    def test_find_everything(self):
        """Test an optimization that finds all tags."""
        soup = self.soup("<a>foo</a><b>bar</b>")
        self.assertEqual(2, len(soup.find_all()))

    def test_find_everything_with_name(self):
        """Test an optimization that finds all tags with a given name."""
        soup = self.soup("<a>foo</a><b>bar</b><a>baz</a>")
        self.assertEqual(2, len(soup.find_all('a')))

class TestFindAll(TreeTest):
    """Basic tests of the find_all() method."""

    def test_find_all_text_nodes(self):
        """You can search the tree for text nodes."""
        soup = self.soup("<html>Foo<b>bar</b>\xbb</html>")
        # Exact match.
        self.assertEqual(soup.find_all(text="bar"), [u"bar"])
        # Match any of a number of strings.
        self.assertEqual(
            soup.find_all(text=["Foo", "bar"]), [u"Foo", u"bar"])
        # Match a regular expression.
        self.assertEqual(soup.find_all(text=re.compile('.*')),
                         [u"Foo", u"bar", u'\xbb'])
        # Match anything.
        self.assertEqual(soup.find_all(text=True),
                         [u"Foo", u"bar", u'\xbb'])

    def test_find_all_limit(self):
        """You can limit the number of items returned by find_all."""
        soup = self.soup("<a>1</a><a>2</a><a>3</a><a>4</a><a>5</a>")
        self.assertSelects(soup.find_all('a', limit=3), ["1", "2", "3"])
        self.assertSelects(soup.find_all('a', limit=1), ["1"])
        self.assertSelects(
            soup.find_all('a', limit=10), ["1", "2", "3", "4", "5"])

        # A limit of 0 means no limit.
        self.assertSelects(
            soup.find_all('a', limit=0), ["1", "2", "3", "4", "5"])

    def test_calling_a_tag_is_calling_findall(self):
        soup = self.soup("<a>1</a><b>2<a id='foo'>3</a></b>")
        self.assertSelects(soup('a', limit=1), ["1"])
        self.assertSelects(soup.b(id="foo"), ["3"])

    def test_find_all_with_self_referential_data_structure_does_not_cause_infinite_recursion(self):
        soup = self.soup("<a></a>")
        # Create a self-referential list.
        l = []
        l.append(l)

        # Without special code in _normalize_search_value, this would cause infinite
        # recursion.
        self.assertEqual([], soup.find_all(l))

    def test_find_all_resultset(self):
        """All find_all calls return a ResultSet"""
        soup = self.soup("<a></a>")
        result = soup.find_all("a")
        self.assertTrue(hasattr(result, "source"))

        result = soup.find_all(True)
        self.assertTrue(hasattr(result, "source"))

        result = soup.find_all(text="foo")
        self.assertTrue(hasattr(result, "source"))


class TestFindAllBasicNamespaces(TreeTest):

    def test_find_by_namespaced_name(self):
        soup = self.soup('<mathml:msqrt>4</mathml:msqrt><a svg:fill="red">')
        self.assertEqual("4", soup.find("mathml:msqrt").string)
        self.assertEqual("a", soup.find(attrs= { "svg:fill" : "red" }).name)


class TestFindAllByName(TreeTest):
    """Test ways of finding tags by tag name."""

    def setUp(self):
        super(TreeTest, self).setUp()
        self.tree =  self.soup("""<a>First tag.</a>
                                  <b>Second tag.</b>
                                  <c>Third <a>Nested tag.</a> tag.</c>""")

    def test_find_all_by_tag_name(self):
        # Find all the <a> tags.
        self.assertSelects(
            self.tree.find_all('a'), ['First tag.', 'Nested tag.'])

    def test_find_all_by_name_and_text(self):
        self.assertSelects(
            self.tree.find_all('a', text='First tag.'), ['First tag.'])

        self.assertSelects(
            self.tree.find_all('a', text=True), ['First tag.', 'Nested tag.'])

        self.assertSelects(
            self.tree.find_all('a', text=re.compile("tag")),
            ['First tag.', 'Nested tag.'])


    def test_find_all_on_non_root_element(self):
        # You can call find_all on any node, not just the root.
        self.assertSelects(self.tree.c.find_all('a'), ['Nested tag.'])

    def test_calling_element_invokes_find_all(self):
        self.assertSelects(self.tree('a'), ['First tag.', 'Nested tag.'])

    def test_find_all_by_tag_strainer(self):
        self.assertSelects(
            self.tree.find_all(SoupStrainer('a')),
            ['First tag.', 'Nested tag.'])

    def test_find_all_by_tag_names(self):
        self.assertSelects(
            self.tree.find_all(['a', 'b']),
            ['First tag.', 'Second tag.', 'Nested tag.'])

    def test_find_all_by_tag_dict(self):
        self.assertSelects(
            self.tree.find_all({'a' : True, 'b' : True}),
            ['First tag.', 'Second tag.', 'Nested tag.'])

    def test_find_all_by_tag_re(self):
        self.assertSelects(
            self.tree.find_all(re.compile('^[ab]$')),
            ['First tag.', 'Second tag.', 'Nested tag.'])

    def test_find_all_with_tags_matching_method(self):
        # You can define an oracle method that determines whether
        # a tag matches the search.
        def id_matches_name(tag):
            return tag.name == tag.get('id')

        tree = self.soup("""<a id="a">Match 1.</a>
                            <a id="1">Does not match.</a>
                            <b id="b">Match 2.</a>""")

        self.assertSelects(
            tree.find_all(id_matches_name), ["Match 1.", "Match 2."])


class TestFindAllByAttribute(TreeTest):

    def test_find_all_by_attribute_name(self):
        # You can pass in keyword arguments to find_all to search by
        # attribute.
        tree = self.soup("""
                         <a id="first">Matching a.</a>
                         <a id="second">
                          Non-matching <b id="first">Matching b.</b>a.
                         </a>""")
        self.assertSelects(tree.find_all(id='first'),
                           ["Matching a.", "Matching b."])

    def test_find_all_by_utf8_attribute_value(self):
        peace = u"םולש".encode("utf8")
        data = u'<a title="םולש"></a>'.encode("utf8")
        soup = self.soup(data)
        self.assertEqual([soup.a], soup.find_all(title=peace))
        self.assertEqual([soup.a], soup.find_all(title=peace.decode("utf8")))
        self.assertEqual([soup.a], soup.find_all(title=[peace, "something else"]))

    def test_find_all_by_attribute_dict(self):
        # You can pass in a dictionary as the argument 'attrs'. This
        # lets you search for attributes like 'name' (a fixed argument
        # to find_all) and 'class' (a reserved word in Python.)
        tree = self.soup("""
                         <a name="name1" class="class1">Name match.</a>
                         <a name="name2" class="class2">Class match.</a>
                         <a name="name3" class="class3">Non-match.</a>
                         <name1>A tag called 'name1'.</name1>
                         """)

        # This doesn't do what you want.
        self.assertSelects(tree.find_all(name='name1'),
                           ["A tag called 'name1'."])
        # This does what you want.
        self.assertSelects(tree.find_all(attrs={'name' : 'name1'}),
                           ["Name match."])

        self.assertSelects(tree.find_all(attrs={'class' : 'class2'}),
                           ["Class match."])

    def test_find_all_by_class(self):
        tree = self.soup("""
                         <a class="1">Class 1.</a>
                         <a class="2">Class 2.</a>
                         <b class="1">Class 1.</b>
                         <c class="3 4">Class 3 and 4.</c>
                         """)

        # Passing in the class_ keyword argument will search against
        # the 'class' attribute.
        self.assertSelects(tree.find_all('a', class_='1'), ['Class 1.'])
        self.assertSelects(tree.find_all('c', class_='3'), ['Class 3 and 4.'])
        self.assertSelects(tree.find_all('c', class_='4'), ['Class 3 and 4.'])

        # Passing in a string to 'attrs' will also search the CSS class.
        self.assertSelects(tree.find_all('a', '1'), ['Class 1.'])
        self.assertSelects(tree.find_all(attrs='1'), ['Class 1.', 'Class 1.'])
        self.assertSelects(tree.find_all('c', '3'), ['Class 3 and 4.'])
        self.assertSelects(tree.find_all('c', '4'), ['Class 3 and 4.'])

    def test_find_by_class_when_multiple_classes_present(self):
        tree = self.soup("<gar class='foo bar'>Found it</gar>")

        f = tree.find_all("gar", class_=re.compile("o"))
        self.assertSelects(f, ["Found it"])

        f = tree.find_all("gar", class_=re.compile("a"))
        self.assertSelects(f, ["Found it"])

        # Since the class is not the string "foo bar", but the two
        # strings "foo" and "bar", this will not find anything.
        f = tree.find_all("gar", class_=re.compile("o b"))
        self.assertSelects(f, [])

    def test_find_all_with_non_dictionary_for_attrs_finds_by_class(self):
        soup = self.soup("<a class='bar'>Found it</a>")

        self.assertSelects(soup.find_all("a", re.compile("ba")), ["Found it"])

        def big_attribute_value(value):
            return len(value) > 3

        self.assertSelects(soup.find_all("a", big_attribute_value), [])

        def small_attribute_value(value):
            return len(value) <= 3

        self.assertSelects(
            soup.find_all("a", small_attribute_value), ["Found it"])

    def test_find_all_with_string_for_attrs_finds_multiple_classes(self):
        soup = self.soup('<a class="foo bar"></a><a class="foo"></a>')
        a, a2 = soup.find_all("a")
        self.assertEqual([a, a2], soup.find_all("a", "foo"))
        self.assertEqual([a], soup.find_all("a", "bar"))

        # If you specify the class as a string that contains a
        # space, only that specific value will be found.
        self.assertEqual([a], soup.find_all("a", class_="foo bar"))
        self.assertEqual([a], soup.find_all("a", "foo bar"))
        self.assertEqual([], soup.find_all("a", "bar foo"))

    def test_find_all_by_attribute_soupstrainer(self):
        tree = self.soup("""
                         <a id="first">Match.</a>
                         <a id="second">Non-match.</a>""")

        strainer = SoupStrainer(attrs={'id' : 'first'})
        self.assertSelects(tree.find_all(strainer), ['Match.'])

    def test_find_all_with_missing_atribute(self):
        # You can pass in None as the value of an attribute to find_all.
        # This will match tags that do not have that attribute set.
        tree = self.soup("""<a id="1">ID present.</a>
                            <a>No ID present.</a>
                            <a id="">ID is empty.</a>""")
        self.assertSelects(tree.find_all('a', id=None), ["No ID present."])

    def test_find_all_with_defined_attribute(self):
        # You can pass in None as the value of an attribute to find_all.
        # This will match tags that have that attribute set to any value.
        tree = self.soup("""<a id="1">ID present.</a>
                            <a>No ID present.</a>
                            <a id="">ID is empty.</a>""")
        self.assertSelects(
            tree.find_all(id=True), ["ID present.", "ID is empty."])

    def test_find_all_with_numeric_attribute(self):
        # If you search for a number, it's treated as a string.
        tree = self.soup("""<a id=1>Unquoted attribute.</a>
                            <a id="1">Quoted attribute.</a>""")

        expected = ["Unquoted attribute.", "Quoted attribute."]
        self.assertSelects(tree.find_all(id=1), expected)
        self.assertSelects(tree.find_all(id="1"), expected)

    def test_find_all_with_list_attribute_values(self):
        # You can pass a list of attribute values instead of just one,
        # and you'll get tags that match any of the values.
        tree = self.soup("""<a id="1">1</a>
                            <a id="2">2</a>
                            <a id="3">3</a>
                            <a>No ID.</a>""")
        self.assertSelects(tree.find_all(id=["1", "3", "4"]),
                           ["1", "3"])

    def test_find_all_with_regular_expression_attribute_value(self):
        # You can pass a regular expression as an attribute value, and
        # you'll get tags whose values for that attribute match the
        # regular expression.
        tree = self.soup("""<a id="a">One a.</a>
                            <a id="aa">Two as.</a>
                            <a id="ab">Mixed as and bs.</a>
                            <a id="b">One b.</a>
                            <a>No ID.</a>""")

        self.assertSelects(tree.find_all(id=re.compile("^a+$")),
                           ["One a.", "Two as."])

    def test_find_by_name_and_containing_string(self):
        soup = self.soup("<b>foo</b><b>bar</b><a>foo</a>")
        a = soup.a

        self.assertEqual([a], soup.find_all("a", text="foo"))
        self.assertEqual([], soup.find_all("a", text="bar"))
        self.assertEqual([], soup.find_all("a", text="bar"))

    def test_find_by_name_and_containing_string_when_string_is_buried(self):
        soup = self.soup("<a>foo</a><a><b><c>foo</c></b></a>")
        self.assertEqual(soup.find_all("a"), soup.find_all("a", text="foo"))

    def test_find_by_attribute_and_containing_string(self):
        soup = self.soup('<b id="1">foo</b><a id="2">foo</a>')
        a = soup.a

        self.assertEqual([a], soup.find_all(id=2, text="foo"))
        self.assertEqual([], soup.find_all(id=1, text="bar"))


class TestIndex(TreeTest):
    """Test Tag.index"""
    def test_index(self):
        tree = self.soup("""<div>
                            <a>Identical</a>
                            <b>Not identical</b>
                            <a>Identical</a>

                            <c><d>Identical with child</d></c>
                            <b>Also not identical</b>
                            <c><d>Identical with child</d></c>
                            </div>""")
        div = tree.div
        for i, element in enumerate(div.contents):
            self.assertEqual(i, div.index(element))
        self.assertRaises(ValueError, tree.index, 1)


class TestParentOperations(TreeTest):
    """Test navigation and searching through an element's parents."""

    def setUp(self):
        super(TestParentOperations, self).setUp()
        self.tree = self.soup('''<ul id="empty"></ul>
                                 <ul id="top">
                                  <ul id="middle">
                                   <ul id="bottom">
                                    <b>Start here</b>
                                   </ul>
                                  </ul>''')
        self.start = self.tree.b


    def test_parent(self):
        self.assertEqual(self.start.parent['id'], 'bottom')
        self.assertEqual(self.start.parent.parent['id'], 'middle')
        self.assertEqual(self.start.parent.parent.parent['id'], 'top')

    def test_parent_of_top_tag_is_soup_object(self):
        top_tag = self.tree.contents[0]
        self.assertEqual(top_tag.parent, self.tree)

    def test_soup_object_has_no_parent(self):
        self.assertEqual(None, self.tree.parent)

    def test_find_parents(self):
        self.assertSelectsIDs(
            self.start.find_parents('ul'), ['bottom', 'middle', 'top'])
        self.assertSelectsIDs(
            self.start.find_parents('ul', id="middle"), ['middle'])

    def test_find_parent(self):
        self.assertEqual(self.start.find_parent('ul')['id'], 'bottom')
        self.assertEqual(self.start.find_parent('ul', id='top')['id'], 'top')

    def test_parent_of_text_element(self):
        text = self.tree.find(text="Start here")
        self.assertEqual(text.parent.name, 'b')

    def test_text_element_find_parent(self):
        text = self.tree.find(text="Start here")
        self.assertEqual(text.find_parent('ul')['id'], 'bottom')

    def test_parent_generator(self):
        parents = [parent['id'] for parent in self.start.parents
                   if parent is not None and 'id' in parent.attrs]
        self.assertEqual(parents, ['bottom', 'middle', 'top'])


class ProximityTest(TreeTest):

    def setUp(self):
        super(TreeTest, self).setUp()
        self.tree = self.soup(
            '<html id="start"><head></head><body><b id="1">One</b><b id="2">Two</b><b id="3">Three</b></body></html>')


class TestNextOperations(ProximityTest):

    def setUp(self):
        super(TestNextOperations, self).setUp()
        self.start = self.tree.b

    def test_next(self):
        self.assertEqual(self.start.next_element, "One")
        self.assertEqual(self.start.next_element.next_element['id'], "2")

    def test_next_of_last_item_is_none(self):
        last = self.tree.find(text="Three")
        self.assertEqual(last.next_element, None)

    def test_next_of_root_is_none(self):
        # The document root is outside the next/previous chain.
        self.assertEqual(self.tree.next_element, None)

    def test_find_all_next(self):
        self.assertSelects(self.start.find_all_next('b'), ["Two", "Three"])
        self.start.find_all_next(id=3)
        self.assertSelects(self.start.find_all_next(id=3), ["Three"])

    def test_find_next(self):
        self.assertEqual(self.start.find_next('b')['id'], '2')
        self.assertEqual(self.start.find_next(text="Three"), "Three")

    def test_find_next_for_text_element(self):
        text = self.tree.find(text="One")
        self.assertEqual(text.find_next("b").string, "Two")
        self.assertSelects(text.find_all_next("b"), ["Two", "Three"])

    def test_next_generator(self):
        start = self.tree.find(text="Two")
        successors = [node for node in start.next_elements]
        # There are two successors: the final <b> tag and its text contents.
        tag, contents = successors
        self.assertEqual(tag['id'], '3')
        self.assertEqual(contents, "Three")

class TestPreviousOperations(ProximityTest):

    def setUp(self):
        super(TestPreviousOperations, self).setUp()
        self.end = self.tree.find(text="Three")

    def test_previous(self):
        self.assertEqual(self.end.previous_element['id'], "3")
        self.assertEqual(self.end.previous_element.previous_element, "Two")

    def test_previous_of_first_item_is_none(self):
        first = self.tree.find('html')
        self.assertEqual(first.previous_element, None)

    def test_previous_of_root_is_none(self):
        # The document root is outside the next/previous chain.
        # XXX This is broken!
        #self.assertEqual(self.tree.previous_element, None)
        pass

    def test_find_all_previous(self):
        # The <b> tag containing the "Three" node is the predecessor
        # of the "Three" node itself, which is why "Three" shows up
        # here.
        self.assertSelects(
            self.end.find_all_previous('b'), ["Three", "Two", "One"])
        self.assertSelects(self.end.find_all_previous(id=1), ["One"])

    def test_find_previous(self):
        self.assertEqual(self.end.find_previous('b')['id'], '3')
        self.assertEqual(self.end.find_previous(text="One"), "One")

    def test_find_previous_for_text_element(self):
        text = self.tree.find(text="Three")
        self.assertEqual(text.find_previous("b").string, "Three")
        self.assertSelects(
            text.find_all_previous("b"), ["Three", "Two", "One"])

    def test_previous_generator(self):
        start = self.tree.find(text="One")
        predecessors = [node for node in start.previous_elements]

        # There are four predecessors: the <b> tag containing "One"
        # the <body> tag, the <head> tag, and the <html> tag.
        b, body, head, html = predecessors
        self.assertEqual(b['id'], '1')
        self.assertEqual(body.name, "body")
        self.assertEqual(head.name, "head")
        self.assertEqual(html.name, "html")


class SiblingTest(TreeTest):

    def setUp(self):
        super(SiblingTest, self).setUp()
        markup = '''<html>
                    <span id="1">
                     <span id="1.1"></span>
                    </span>
                    <span id="2">
                     <span id="2.1"></span>
                    </span>
                    <span id="3">
                     <span id="3.1"></span>
                    </span>
                    <span id="4"></span>
                    </html>'''
        # All that whitespace looks good but makes the tests more
        # difficult. Get rid of it.
        markup = re.compile("\n\s*").sub("", markup)
        self.tree = self.soup(markup)


class TestNextSibling(SiblingTest):

    def setUp(self):
        super(TestNextSibling, self).setUp()
        self.start = self.tree.find(id="1")

    def test_next_sibling_of_root_is_none(self):
        self.assertEqual(self.tree.next_sibling, None)

    def test_next_sibling(self):
        self.assertEqual(self.start.next_sibling['id'], '2')
        self.assertEqual(self.start.next_sibling.next_sibling['id'], '3')

        # Note the difference between next_sibling and next_element.
        self.assertEqual(self.start.next_element['id'], '1.1')

    def test_next_sibling_may_not_exist(self):
        self.assertEqual(self.tree.html.next_sibling, None)

        nested_span = self.tree.find(id="1.1")
        self.assertEqual(nested_span.next_sibling, None)

        last_span = self.tree.find(id="4")
        self.assertEqual(last_span.next_sibling, None)

    def test_find_next_sibling(self):
        self.assertEqual(self.start.find_next_sibling('span')['id'], '2')

    def test_next_siblings(self):
        self.assertSelectsIDs(self.start.find_next_siblings("span"),
                              ['2', '3', '4'])

        self.assertSelectsIDs(self.start.find_next_siblings(id='3'), ['3'])

    def test_next_sibling_for_text_element(self):
        soup = self.soup("Foo<b>bar</b>baz")
        start = soup.find(text="Foo")
        self.assertEqual(start.next_sibling.name, 'b')
        self.assertEqual(start.next_sibling.next_sibling, 'baz')

        self.assertSelects(start.find_next_siblings('b'), ['bar'])
        self.assertEqual(start.find_next_sibling(text="baz"), "baz")
        self.assertEqual(start.find_next_sibling(text="nonesuch"), None)


class TestPreviousSibling(SiblingTest):

    def setUp(self):
        super(TestPreviousSibling, self).setUp()
        self.end = self.tree.find(id="4")

    def test_previous_sibling_of_root_is_none(self):
        self.assertEqual(self.tree.previous_sibling, None)

    def test_previous_sibling(self):
        self.assertEqual(self.end.previous_sibling['id'], '3')
        self.assertEqual(self.end.previous_sibling.previous_sibling['id'], '2')

        # Note the difference between previous_sibling and previous_element.
        self.assertEqual(self.end.previous_element['id'], '3.1')

    def test_previous_sibling_may_not_exist(self):
        self.assertEqual(self.tree.html.previous_sibling, None)

        nested_span = self.tree.find(id="1.1")
        self.assertEqual(nested_span.previous_sibling, None)

        first_span = self.tree.find(id="1")
        self.assertEqual(first_span.previous_sibling, None)

    def test_find_previous_sibling(self):
        self.assertEqual(self.end.find_previous_sibling('span')['id'], '3')

    def test_previous_siblings(self):
        self.assertSelectsIDs(self.end.find_previous_siblings("span"),
                              ['3', '2', '1'])

        self.assertSelectsIDs(self.end.find_previous_siblings(id='1'), ['1'])

    def test_previous_sibling_for_text_element(self):
        soup = self.soup("Foo<b>bar</b>baz")
        start = soup.find(text="baz")
        self.assertEqual(start.previous_sibling.name, 'b')
        self.assertEqual(start.previous_sibling.previous_sibling, 'Foo')

        self.assertSelects(start.find_previous_siblings('b'), ['bar'])
        self.assertEqual(start.find_previous_sibling(text="Foo"), "Foo")
        self.assertEqual(start.find_previous_sibling(text="nonesuch"), None)


class TestTagCreation(SoupTest):
    """Test the ability to create new tags."""
    def test_new_tag(self):
        soup = self.soup("")
        new_tag = soup.new_tag("foo", bar="baz")
        self.assertTrue(isinstance(new_tag, Tag))
        self.assertEqual("foo", new_tag.name)
        self.assertEqual(dict(bar="baz"), new_tag.attrs)
        self.assertEqual(None, new_tag.parent)

    def test_tag_inherits_self_closing_rules_from_builder(self):
        if XML_BUILDER_PRESENT:
            xml_soup = BeautifulSoup("", "xml")
            xml_br = xml_soup.new_tag("br")
            xml_p = xml_soup.new_tag("p")

            # Both the <br> and <p> tag are empty-element, just because
            # they have no contents.
            self.assertEqual(b"<br/>", xml_br.encode())
            self.assertEqual(b"<p/>", xml_p.encode())

        html_soup = BeautifulSoup("", "html")
        html_br = html_soup.new_tag("br")
        html_p = html_soup.new_tag("p")

        # The HTML builder users HTML's rules about which tags are
        # empty-element tags, and the new tags reflect these rules.
        self.assertEqual(b"<br/>", html_br.encode())
        self.assertEqual(b"<p></p>", html_p.encode())

    def test_new_string_creates_navigablestring(self):
        soup = self.soup("")
        s = soup.new_string("foo")
        self.assertEqual("foo", s)
        self.assertTrue(isinstance(s, NavigableString))

    def test_new_string_can_create_navigablestring_subclass(self):
        soup = self.soup("")
        s = soup.new_string("foo", Comment)
        self.assertEqual("foo", s)
        self.assertTrue(isinstance(s, Comment))

class TestTreeModification(SoupTest):

    def test_attribute_modification(self):
        soup = self.soup('<a id="1"></a>')
        soup.a['id'] = 2
        self.assertEqual(soup.decode(), self.document_for('<a id="2"></a>'))
        del(soup.a['id'])
        self.assertEqual(soup.decode(), self.document_for('<a></a>'))
        soup.a['id2'] = 'foo'
        self.assertEqual(soup.decode(), self.document_for('<a id2="foo"></a>'))

    def test_new_tag_creation(self):
        builder = builder_registry.lookup('html')()
        soup = self.soup("<body></body>", builder=builder)
        a = Tag(soup, builder, 'a')
        ol = Tag(soup, builder, 'ol')
        a['href'] = 'http://foo.com/'
        soup.body.insert(0, a)
        soup.body.insert(1, ol)
        self.assertEqual(
            soup.body.encode(),
            b'<body><a href="http://foo.com/"></a><ol></ol></body>')

    def test_append_to_contents_moves_tag(self):
        doc = """<p id="1">Don't leave me <b>here</b>.</p>
                <p id="2">Don\'t leave!</p>"""
        soup = self.soup(doc)
        second_para = soup.find(id='2')
        bold = soup.b

        # Move the <b> tag to the end of the second paragraph.
        soup.find(id='2').append(soup.b)

        # The <b> tag is now a child of the second paragraph.
        self.assertEqual(bold.parent, second_para)

        self.assertEqual(
            soup.decode(), self.document_for(
                '<p id="1">Don\'t leave me .</p>\n'
                '<p id="2">Don\'t leave!<b>here</b></p>'))

    def test_replace_with_returns_thing_that_was_replaced(self):
        text = "<a></a><b><c></c></b>"
        soup = self.soup(text)
        a = soup.a
        new_a = a.replace_with(soup.c)
        self.assertEqual(a, new_a)

    def test_unwrap_returns_thing_that_was_replaced(self):
        text = "<a><b></b><c></c></a>"
        soup = self.soup(text)
        a = soup.a
        new_a = a.unwrap()
        self.assertEqual(a, new_a)

    def test_replace_tag_with_itself(self):
        text = "<a><b></b><c>Foo<d></d></c></a><a><e></e></a>"
        soup = self.soup(text)
        c = soup.c
        soup.c.replace_with(c)
        self.assertEqual(soup.decode(), self.document_for(text))

    def test_replace_tag_with_its_parent_raises_exception(self):
        text = "<a><b></b></a>"
        soup = self.soup(text)
        self.assertRaises(ValueError, soup.b.replace_with, soup.a)

    def test_insert_tag_into_itself_raises_exception(self):
        text = "<a><b></b></a>"
        soup = self.soup(text)
        self.assertRaises(ValueError, soup.a.insert, 0, soup.a)

    def test_replace_with_maintains_next_element_throughout(self):
        soup = self.soup('<p><a>one</a><b>three</b></p>')
        a = soup.a
        b = a.contents[0]
        # Make it so the <a> tag has two text children.
        a.insert(1, "two")

        # Now replace each one with the empty string.
        left, right = a.contents
        left.replaceWith('')
        right.replaceWith('')

        # The <b> tag is still connected to the tree.
        self.assertEqual("three", soup.b.string)

    def test_replace_final_node(self):
        soup = self.soup("<b>Argh!</b>")
        soup.find(text="Argh!").replace_with("Hooray!")
        new_text = soup.find(text="Hooray!")
        b = soup.b
        self.assertEqual(new_text.previous_element, b)
        self.assertEqual(new_text.parent, b)
        self.assertEqual(new_text.previous_element.next_element, new_text)
        self.assertEqual(new_text.next_element, None)

    def test_consecutive_text_nodes(self):
        # A builder should never create two consecutive text nodes,
        # but if you insert one next to another, Beautiful Soup will
        # handle it correctly.
        soup = self.soup("<a><b>Argh!</b><c></c></a>")
        soup.b.insert(1, "Hooray!")

        self.assertEqual(
            soup.decode(), self.document_for(
                "<a><b>Argh!Hooray!</b><c></c></a>"))

        new_text = soup.find(text="Hooray!")
        self.assertEqual(new_text.previous_element, "Argh!")
        self.assertEqual(new_text.previous_element.next_element, new_text)

        self.assertEqual(new_text.previous_sibling, "Argh!")
        self.assertEqual(new_text.previous_sibling.next_sibling, new_text)

        self.assertEqual(new_text.next_sibling, None)
        self.assertEqual(new_text.next_element, soup.c)

    def test_insert_string(self):
        soup = self.soup("<a></a>")
        soup.a.insert(0, "bar")
        soup.a.insert(0, "foo")
        # The string were added to the tag.
        self.assertEqual(["foo", "bar"], soup.a.contents)
        # And they were converted to NavigableStrings.
        self.assertEqual(soup.a.contents[0].next_element, "bar")

    def test_insert_tag(self):
        builder = self.default_builder
        soup = self.soup(
            "<a><b>Find</b><c>lady!</c><d></d></a>", builder=builder)
        magic_tag = Tag(soup, builder, 'magictag')
        magic_tag.insert(0, "the")
        soup.a.insert(1, magic_tag)

        self.assertEqual(
            soup.decode(), self.document_for(
                "<a><b>Find</b><magictag>the</magictag><c>lady!</c><d></d></a>"))

        # Make sure all the relationships are hooked up correctly.
        b_tag = soup.b
        self.assertEqual(b_tag.next_sibling, magic_tag)
        self.assertEqual(magic_tag.previous_sibling, b_tag)

        find = b_tag.find(text="Find")
        self.assertEqual(find.next_element, magic_tag)
        self.assertEqual(magic_tag.previous_element, find)

        c_tag = soup.c
        self.assertEqual(magic_tag.next_sibling, c_tag)
        self.assertEqual(c_tag.previous_sibling, magic_tag)

        the = magic_tag.find(text="the")
        self.assertEqual(the.parent, magic_tag)
        self.assertEqual(the.next_element, c_tag)
        self.assertEqual(c_tag.previous_element, the)

    def test_append_child_thats_already_at_the_end(self):
        data = "<a><b></b></a>"
        soup = self.soup(data)
        soup.a.append(soup.b)
        self.assertEqual(data, soup.decode())

    def test_move_tag_to_beginning_of_parent(self):
        data = "<a><b></b><c></c><d></d></a>"
        soup = self.soup(data)
        soup.a.insert(0, soup.d)
        self.assertEqual("<a><d></d><b></b><c></c></a>", soup.decode())

    def test_insert_works_on_empty_element_tag(self):
        # This is a little strange, since most HTML parsers don't allow
        # markup like this to come through. But in general, we don't
        # know what the parser would or wouldn't have allowed, so
        # I'm letting this succeed for now.
        soup = self.soup("<br/>")
        soup.br.insert(1, "Contents")
        self.assertEqual(str(soup.br), "<br>Contents</br>")

    def test_insert_before(self):
        soup = self.soup("<a>foo</a><b>bar</b>")
        soup.b.insert_before("BAZ")
        soup.a.insert_before("QUUX")
        self.assertEqual(
            soup.decode(), self.document_for("QUUX<a>foo</a>BAZ<b>bar</b>"))

        soup.a.insert_before(soup.b)
        self.assertEqual(
            soup.decode(), self.document_for("QUUX<b>bar</b><a>foo</a>BAZ"))

    def test_insert_after(self):
        soup = self.soup("<a>foo</a><b>bar</b>")
        soup.b.insert_after("BAZ")
        soup.a.insert_after("QUUX")
        self.assertEqual(
            soup.decode(), self.document_for("<a>foo</a>QUUX<b>bar</b>BAZ"))
        soup.b.insert_after(soup.a)
        self.assertEqual(
            soup.decode(), self.document_for("QUUX<b>bar</b><a>foo</a>BAZ"))

    def test_insert_after_raises_exception_if_after_has_no_meaning(self):
        soup = self.soup("")
        tag = soup.new_tag("a")
        string = soup.new_string("")
        self.assertRaises(ValueError, string.insert_after, tag)
        self.assertRaises(NotImplementedError, soup.insert_after, tag)
        self.assertRaises(ValueError, tag.insert_after, tag)

    def test_insert_before_raises_notimplementederror_if_before_has_no_meaning(self):
        soup = self.soup("")
        tag = soup.new_tag("a")
        string = soup.new_string("")
        self.assertRaises(ValueError, string.insert_before, tag)
        self.assertRaises(NotImplementedError, soup.insert_before, tag)
        self.assertRaises(ValueError, tag.insert_before, tag)

    def test_replace_with(self):
        soup = self.soup(
                "<p>There's <b>no</b> business like <b>show</b> business</p>")
        no, show = soup.find_all('b')
        show.replace_with(no)
        self.assertEqual(
            soup.decode(),
            self.document_for(
                "<p>There's  business like <b>no</b> business</p>"))

        self.assertEqual(show.parent, None)
        self.assertEqual(no.parent, soup.p)
        self.assertEqual(no.next_element, "no")
        self.assertEqual(no.next_sibling, " business")

    def test_replace_first_child(self):
        data = "<a><b></b><c></c></a>"
        soup = self.soup(data)
        soup.b.replace_with(soup.c)
        self.assertEqual("<a><c></c></a>", soup.decode())

    def test_replace_last_child(self):
        data = "<a><b></b><c></c></a>"
        soup = self.soup(data)
        soup.c.replace_with(soup.b)
        self.assertEqual("<a><b></b></a>", soup.decode())

    def test_nested_tag_replace_with(self):
        soup = self.soup(
            """<a>We<b>reserve<c>the</c><d>right</d></b></a><e>to<f>refuse</f><g>service</g></e>""")

        # Replace the entire <b> tag and its contents ("reserve the
        # right") with the <f> tag ("refuse").
        remove_tag = soup.b
        move_tag = soup.f
        remove_tag.replace_with(move_tag)

        self.assertEqual(
            soup.decode(), self.document_for(
                "<a>We<f>refuse</f></a><e>to<g>service</g></e>"))

        # The <b> tag is now an orphan.
        self.assertEqual(remove_tag.parent, None)
        self.assertEqual(remove_tag.find(text="right").next_element, None)
        self.assertEqual(remove_tag.previous_element, None)
        self.assertEqual(remove_tag.next_sibling, None)
        self.assertEqual(remove_tag.previous_sibling, None)

        # The <f> tag is now connected to the <a> tag.
        self.assertEqual(move_tag.parent, soup.a)
        self.assertEqual(move_tag.previous_element, "We")
        self.assertEqual(move_tag.next_element.next_element, soup.e)
        self.assertEqual(move_tag.next_sibling, None)

        # The gap where the <f> tag used to be has been mended, and
        # the word "to" is now connected to the <g> tag.
        to_text = soup.find(text="to")
        g_tag = soup.g
        self.assertEqual(to_text.next_element, g_tag)
        self.assertEqual(to_text.next_sibling, g_tag)
        self.assertEqual(g_tag.previous_element, to_text)
        self.assertEqual(g_tag.previous_sibling, to_text)

    def test_unwrap(self):
        tree = self.soup("""
            <p>Unneeded <em>formatting</em> is unneeded</p>
            """)
        tree.em.unwrap()
        self.assertEqual(tree.em, None)
        self.assertEqual(tree.p.text, "Unneeded formatting is unneeded")

    def test_wrap(self):
        soup = self.soup("I wish I was bold.")
        value = soup.string.wrap(soup.new_tag("b"))
        self.assertEqual(value.decode(), "<b>I wish I was bold.</b>")
        self.assertEqual(
            soup.decode(), self.document_for("<b>I wish I was bold.</b>"))

    def test_wrap_extracts_tag_from_elsewhere(self):
        soup = self.soup("<b></b>I wish I was bold.")
        soup.b.next_sibling.wrap(soup.b)
        self.assertEqual(
            soup.decode(), self.document_for("<b>I wish I was bold.</b>"))

    def test_wrap_puts_new_contents_at_the_end(self):
        soup = self.soup("<b>I like being bold.</b>I wish I was bold.")
        soup.b.next_sibling.wrap(soup.b)
        self.assertEqual(2, len(soup.b.contents))
        self.assertEqual(
            soup.decode(), self.document_for(
                "<b>I like being bold.I wish I was bold.</b>"))

    def test_extract(self):
        soup = self.soup(
            '<html><body>Some content. <div id="nav">Nav crap</div> More content.</body></html>')

        self.assertEqual(len(soup.body.contents), 3)
        extracted = soup.find(id="nav").extract()

        self.assertEqual(
            soup.decode(), "<html><body>Some content.  More content.</body></html>")
        self.assertEqual(extracted.decode(), '<div id="nav">Nav crap</div>')

        # The extracted tag is now an orphan.
        self.assertEqual(len(soup.body.contents), 2)
        self.assertEqual(extracted.parent, None)
        self.assertEqual(extracted.previous_element, None)
        self.assertEqual(extracted.next_element.next_element, None)

        # The gap where the extracted tag used to be has been mended.
        content_1 = soup.find(text="Some content. ")
        content_2 = soup.find(text=" More content.")
        self.assertEqual(content_1.next_element, content_2)
        self.assertEqual(content_1.next_sibling, content_2)
        self.assertEqual(content_2.previous_element, content_1)
        self.assertEqual(content_2.previous_sibling, content_1)

    def test_extract_distinguishes_between_identical_strings(self):
        soup = self.soup("<a>foo</a><b>bar</b>")
        foo_1 = soup.a.string
        bar_1 = soup.b.string
        foo_2 = soup.new_string("foo")
        bar_2 = soup.new_string("bar")
        soup.a.append(foo_2)
        soup.b.append(bar_2)

        # Now there are two identical strings in the <a> tag, and two
        # in the <b> tag. Let's remove the first "foo" and the second
        # "bar".
        foo_1.extract()
        bar_2.extract()
        self.assertEqual(foo_2, soup.a.string)
        self.assertEqual(bar_2, soup.b.string)

    def test_clear(self):
        """Tag.clear()"""
        soup = self.soup("<p><a>String <em>Italicized</em></a> and another</p>")
        # clear using extract()
        a = soup.a
        soup.p.clear()
        self.assertEqual(len(soup.p.contents), 0)
        self.assertTrue(hasattr(a, "contents"))

        # clear using decompose()
        em = a.em
        a.clear(decompose=True)
        self.assertEqual(0, len(em.contents))

    def test_string_set(self):
        """Tag.string = 'string'"""
        soup = self.soup("<a></a> <b><c></c></b>")
        soup.a.string = "foo"
        self.assertEqual(soup.a.contents, ["foo"])
        soup.b.string = "bar"
        self.assertEqual(soup.b.contents, ["bar"])

    def test_string_set_does_not_affect_original_string(self):
        soup = self.soup("<a><b>foo</b><c>bar</c>")
        soup.b.string = soup.c.string
        self.assertEqual(soup.a.encode(), b"<a><b>bar</b><c>bar</c></a>")

    def test_set_string_preserves_class_of_string(self):
        soup = self.soup("<a></a>")
        cdata = CData("foo")
        soup.a.string = cdata
        self.assertTrue(isinstance(soup.a.string, CData))

class TestElementObjects(SoupTest):
    """Test various features of element objects."""

    def test_len(self):
        """The length of an element is its number of children."""
        soup = self.soup("<top>1<b>2</b>3</top>")

        # The BeautifulSoup object itself contains one element: the
        # <top> tag.
        self.assertEqual(len(soup.contents), 1)
        self.assertEqual(len(soup), 1)

        # The <top> tag contains three elements: the text node "1", the
        # <b> tag, and the text node "3".
        self.assertEqual(len(soup.top), 3)
        self.assertEqual(len(soup.top.contents), 3)

    def test_member_access_invokes_find(self):
        """Accessing a Python member .foo invokes find('foo')"""
        soup = self.soup('<b><i></i></b>')
        self.assertEqual(soup.b, soup.find('b'))
        self.assertEqual(soup.b.i, soup.find('b').find('i'))
        self.assertEqual(soup.a, None)

    def test_deprecated_member_access(self):
        soup = self.soup('<b><i></i></b>')
        with warnings.catch_warnings(record=True) as w:
            tag = soup.bTag
        self.assertEqual(soup.b, tag)
        self.assertEqual(
            '.bTag is deprecated, use .find("b") instead.',
            str(w[0].message))

    def test_has_attr(self):
        """has_attr() checks for the presence of an attribute.

        Please note note: has_attr() is different from
        __in__. has_attr() checks the tag's attributes and __in__
        checks the tag's chidlren.
        """
        soup = self.soup("<foo attr='bar'>")
        self.assertTrue(soup.foo.has_attr('attr'))
        self.assertFalse(soup.foo.has_attr('attr2'))


    def test_attributes_come_out_in_alphabetical_order(self):
        markup = '<b a="1" z="5" m="3" f="2" y="4"></b>'
        self.assertSoupEquals(markup, '<b a="1" f="2" m="3" y="4" z="5"></b>')

    def test_string(self):
        # A tag that contains only a text node makes that node
        # available as .string.
        soup = self.soup("<b>foo</b>")
        self.assertEqual(soup.b.string, 'foo')

    def test_empty_tag_has_no_string(self):
        # A tag with no children has no .stirng.
        soup = self.soup("<b></b>")
        self.assertEqual(soup.b.string, None)

    def test_tag_with_multiple_children_has_no_string(self):
        # A tag with no children has no .string.
        soup = self.soup("<a>foo<b></b><b></b></b>")
        self.assertEqual(soup.b.string, None)

        soup = self.soup("<a>foo<b></b>bar</b>")
        self.assertEqual(soup.b.string, None)

        # Even if all the children are strings, due to trickery,
        # it won't work--but this would be a good optimization.
        soup = self.soup("<a>foo</b>")
        soup.a.insert(1, "bar")
        self.assertEqual(soup.a.string, None)

    def test_tag_with_recursive_string_has_string(self):
        # A tag with a single child which has a .string inherits that
        # .string.
        soup = self.soup("<a><b>foo</b></a>")
        self.assertEqual(soup.a.string, "foo")
        self.assertEqual(soup.string, "foo")

    def test_lack_of_string(self):
        """Only a tag containing a single text node has a .string."""
        soup = self.soup("<b>f<i>e</i>o</b>")
        self.assertFalse(soup.b.string)

        soup = self.soup("<b></b>")
        self.assertFalse(soup.b.string)

    def test_all_text(self):
        """Tag.text and Tag.get_text(sep=u"") -> all child text, concatenated"""
        soup = self.soup("<a>a<b>r</b>   <r> t </r></a>")
        self.assertEqual(soup.a.text, "ar  t ")
        self.assertEqual(soup.a.get_text(strip=True), "art")
        self.assertEqual(soup.a.get_text(","), "a,r, , t ")
        self.assertEqual(soup.a.get_text(",", strip=True), "a,r,t")

    def test_get_text_ignores_comments(self):
        soup = self.soup("foo<!--IGNORE-->bar")
        self.assertEqual(soup.get_text(), "foobar")

        self.assertEqual(
            soup.get_text(types=(NavigableString, Comment)), "fooIGNOREbar")
        self.assertEqual(
            soup.get_text(types=None), "fooIGNOREbar")

    def test_all_strings_ignores_comments(self):
        soup = self.soup("foo<!--IGNORE-->bar")
        self.assertEqual(['foo', 'bar'], list(soup.strings))

class TestCDAtaListAttributes(SoupTest):

    """Testing cdata-list attributes like 'class'.
    """
    def test_single_value_becomes_list(self):
        soup = self.soup("<a class='foo'>")
        self.assertEqual(["foo"],soup.a['class'])

    def test_multiple_values_becomes_list(self):
        soup = self.soup("<a class='foo bar'>")
        self.assertEqual(["foo", "bar"], soup.a['class'])

    def test_multiple_values_separated_by_weird_whitespace(self):
        soup = self.soup("<a class='foo\tbar\nbaz'>")
        self.assertEqual(["foo", "bar", "baz"],soup.a['class'])

    def test_attributes_joined_into_string_on_output(self):
        soup = self.soup("<a class='foo\tbar'>")
        self.assertEqual(b'<a class="foo bar"></a>', soup.a.encode())

    def test_accept_charset(self):
        soup = self.soup('<form accept-charset="ISO-8859-1 UTF-8">')
        self.assertEqual(['ISO-8859-1', 'UTF-8'], soup.form['accept-charset'])

    def test_cdata_attribute_applying_only_to_one_tag(self):
        data = '<a accept-charset="ISO-8859-1 UTF-8"></a>'
        soup = self.soup(data)
        # We saw in another test that accept-charset is a cdata-list
        # attribute for the <form> tag. But it's not a cdata-list
        # attribute for any other tag.
        self.assertEqual('ISO-8859-1 UTF-8', soup.a['accept-charset'])

    def test_string_has_immutable_name_property(self):
        string = self.soup("s").string
        self.assertEqual(None, string.name)
        def t():
            string.name = 'foo'
        self.assertRaises(AttributeError, t)

class TestPersistence(SoupTest):
    "Testing features like pickle and deepcopy."

    def setUp(self):
        super(TestPersistence, self).setUp()
        self.page = """<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
"http://www.w3.org/TR/REC-html40/transitional.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Beautiful Soup: We called him Tortoise because he taught us.</title>
<link rev="made" href="mailto:leonardr@segfault.org">
<meta name="Description" content="Beautiful Soup: an HTML parser optimized for screen-scraping.">
<meta name="generator" content="Markov Approximation 1.4 (module: leonardr)">
<meta name="author" content="Leonard Richardson">
</head>
<body>
<a href="foo">foo</a>
<a href="foo"><b>bar</b></a>
</body>
</html>"""
        self.tree = self.soup(self.page)

    def test_pickle_and_unpickle_identity(self):
        # Pickling a tree, then unpickling it, yields a tree identical
        # to the original.
        dumped = pickle.dumps(self.tree, 2)
        loaded = pickle.loads(dumped)
        self.assertEqual(loaded.__class__, BeautifulSoup)
        self.assertEqual(loaded.decode(), self.tree.decode())

    def test_deepcopy_identity(self):
        # Making a deepcopy of a tree yields an identical tree.
        copied = copy.deepcopy(self.tree)
        self.assertEqual(copied.decode(), self.tree.decode())

    def test_unicode_pickle(self):
        # A tree containing Unicode characters can be pickled.
        html = u"<b>\N{SNOWMAN}</b>"
        soup = self.soup(html)
        dumped = pickle.dumps(soup, pickle.HIGHEST_PROTOCOL)
        loaded = pickle.loads(dumped)
        self.assertEqual(loaded.decode(), soup.decode())


class TestSubstitutions(SoupTest):

    def test_default_formatter_is_minimal(self):
        markup = u"<b>&lt;&lt;Sacr\N{LATIN SMALL LETTER E WITH ACUTE} bleu!&gt;&gt;</b>"
        soup = self.soup(markup)
        decoded = soup.decode(formatter="minimal")
        # The < is converted back into &lt; but the e-with-acute is left alone.
        self.assertEqual(
            decoded,
            self.document_for(
                u"<b>&lt;&lt;Sacr\N{LATIN SMALL LETTER E WITH ACUTE} bleu!&gt;&gt;</b>"))

    def test_formatter_html(self):
        markup = u"<b>&lt;&lt;Sacr\N{LATIN SMALL LETTER E WITH ACUTE} bleu!&gt;&gt;</b>"
        soup = self.soup(markup)
        decoded = soup.decode(formatter="html")
        self.assertEqual(
            decoded,
            self.document_for("<b>&lt;&lt;Sacr&eacute; bleu!&gt;&gt;</b>"))

    def test_formatter_minimal(self):
        markup = u"<b>&lt;&lt;Sacr\N{LATIN SMALL LETTER E WITH ACUTE} bleu!&gt;&gt;</b>"
        soup = self.soup(markup)
        decoded = soup.decode(formatter="minimal")
        # The < is converted back into &lt; but the e-with-acute is left alone.
        self.assertEqual(
            decoded,
            self.document_for(
                u"<b>&lt;&lt;Sacr\N{LATIN SMALL LETTER E WITH ACUTE} bleu!&gt;&gt;</b>"))

    def test_formatter_null(self):
        markup = u"<b>&lt;&lt;Sacr\N{LATIN SMALL LETTER E WITH ACUTE} bleu!&gt;&gt;</b>"
        soup = self.soup(markup)
        decoded = soup.decode(formatter=None)
        # Neither the angle brackets nor the e-with-acute are converted.
        # This is not valid HTML, but it's what the user wanted.
        self.assertEqual(decoded,
                          self.document_for(u"<b><<Sacr\N{LATIN SMALL LETTER E WITH ACUTE} bleu!>></b>"))

    def test_formatter_custom(self):
        markup = u"<b>&lt;foo&gt;</b><b>bar</b>"
        soup = self.soup(markup)
        decoded = soup.decode(formatter = lambda x: x.upper())
        # Instead of normal entity conversion code, the custom
        # callable is called on every string.
        self.assertEqual(
            decoded,
            self.document_for(u"<b><FOO></b><b>BAR</b>"))

    def test_formatter_is_run_on_attribute_values(self):
        markup = u'<a href="http://a.com?a=b&c=é">e</a>'
        soup = self.soup(markup)
        a = soup.a

        expect_minimal = u'<a href="http://a.com?a=b&amp;c=é">e</a>'

        self.assertEqual(expect_minimal, a.decode())
        self.assertEqual(expect_minimal, a.decode(formatter="minimal"))

        expect_html = u'<a href="http://a.com?a=b&amp;c=&eacute;">e</a>'
        self.assertEqual(expect_html, a.decode(formatter="html"))

        self.assertEqual(markup, a.decode(formatter=None))
        expect_upper = u'<a href="HTTP://A.COM?A=B&C=É">E</a>'
        self.assertEqual(expect_upper, a.decode(formatter=lambda x: x.upper()))

    def test_formatter_skips_script_tag_for_html_documents(self):
        doc = """
  <script type="text/javascript">
   console.log("< < hey > > ");
  </script>
"""
        encoded = BeautifulSoup(doc).encode()
        self.assertTrue(b"< < hey > >" in encoded)

    def test_formatter_skips_style_tag_for_html_documents(self):
        doc = """
  <style type="text/css">
   console.log("< < hey > > ");
  </style>
"""
        encoded = BeautifulSoup(doc).encode()
        self.assertTrue(b"< < hey > >" in encoded)

    def test_prettify_leaves_preformatted_text_alone(self):
        soup = self.soup("<div>  foo  <pre>  \tbar\n  \n  </pre>  baz  ")
        # Everything outside the <pre> tag is reformatted, but everything
        # inside is left alone.
        self.assertEqual(
            u'<div>\n foo\n <pre>  \tbar\n  \n  </pre>\n baz\n</div>',
            soup.div.prettify())

    def test_prettify_accepts_formatter(self):
        soup = BeautifulSoup("<html><body>foo</body></html>")
        pretty = soup.prettify(formatter = lambda x: x.upper())
        self.assertTrue("FOO" in pretty)

    def test_prettify_outputs_unicode_by_default(self):
        soup = self.soup("<a></a>")
        self.assertEqual(unicode, type(soup.prettify()))

    def test_prettify_can_encode_data(self):
        soup = self.soup("<a></a>")
        self.assertEqual(bytes, type(soup.prettify("utf-8")))

    def test_html_entity_substitution_off_by_default(self):
        markup = u"<b>Sacr\N{LATIN SMALL LETTER E WITH ACUTE} bleu!</b>"
        soup = self.soup(markup)
        encoded = soup.b.encode("utf-8")
        self.assertEqual(encoded, markup.encode('utf-8'))

    def test_encoding_substitution(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"/>')
        soup = self.soup(meta_tag)

        # Parse the document, and the charset apprears unchanged.
        self.assertEqual(soup.meta['content'], 'text/html; charset=x-sjis')

        # Encode the document into some encoding, and the encoding is
        # substituted into the meta tag.
        utf_8 = soup.encode("utf-8")
        self.assertTrue(b"charset=utf-8" in utf_8)

        euc_jp = soup.encode("euc_jp")
        self.assertTrue(b"charset=euc_jp" in euc_jp)

        shift_jis = soup.encode("shift-jis")
        self.assertTrue(b"charset=shift-jis" in shift_jis)

        utf_16_u = soup.encode("utf-16").decode("utf-16")
        self.assertTrue("charset=utf-16" in utf_16_u)

    def test_encoding_substitution_doesnt_happen_if_tag_is_strained(self):
        markup = ('<head><meta content="text/html; charset=x-sjis" '
                    'http-equiv="Content-type"/></head><pre>foo</pre>')

        # Beautiful Soup used to try to rewrite the meta tag even if the
        # meta tag got filtered out by the strainer. This test makes
        # sure that doesn't happen.
        strainer = SoupStrainer('pre')
        soup = self.soup(markup, parse_only=strainer)
        self.assertEqual(soup.contents[0].name, 'pre')

class TestEncoding(SoupTest):
    """Test the ability to encode objects into strings."""

    def test_unicode_string_can_be_encoded(self):
        html = u"<b>\N{SNOWMAN}</b>"
        soup = self.soup(html)
        self.assertEqual(soup.b.string.encode("utf-8"),
                          u"\N{SNOWMAN}".encode("utf-8"))

    def test_tag_containing_unicode_string_can_be_encoded(self):
        html = u"<b>\N{SNOWMAN}</b>"
        soup = self.soup(html)
        self.assertEqual(
            soup.b.encode("utf-8"), html.encode("utf-8"))

    def test_encoding_substitutes_unrecognized_characters_by_default(self):
        html = u"<b>\N{SNOWMAN}</b>"
        soup = self.soup(html)
        self.assertEqual(soup.b.encode("ascii"), b"<b>&#9731;</b>")

    def test_encoding_can_be_made_strict(self):
        html = u"<b>\N{SNOWMAN}</b>"
        soup = self.soup(html)
        self.assertRaises(
            UnicodeEncodeError, soup.encode, "ascii", errors="strict")

    def test_decode_contents(self):
        html = u"<b>\N{SNOWMAN}</b>"
        soup = self.soup(html)
        self.assertEqual(u"\N{SNOWMAN}", soup.b.decode_contents())

    def test_encode_contents(self):
        html = u"<b>\N{SNOWMAN}</b>"
        soup = self.soup(html)
        self.assertEqual(
            u"\N{SNOWMAN}".encode("utf8"), soup.b.encode_contents(
                encoding="utf8"))

    def test_deprecated_renderContents(self):
        html = u"<b>\N{SNOWMAN}</b>"
        soup = self.soup(html)
        self.assertEqual(
            u"\N{SNOWMAN}".encode("utf8"), soup.b.renderContents())

class TestNavigableStringSubclasses(SoupTest):

    def test_cdata(self):
        # None of the current builders turn CDATA sections into CData
        # objects, but you can create them manually.
        soup = self.soup("")
        cdata = CData("foo")
        soup.insert(1, cdata)
        self.assertEqual(str(soup), "<![CDATA[foo]]>")
        self.assertEqual(soup.find(text="foo"), "foo")
        self.assertEqual(soup.contents[0], "foo")

    def test_cdata_is_never_formatted(self):
        """Text inside a CData object is passed into the formatter.

        But the return value is ignored.
        """

        self.count = 0
        def increment(*args):
            self.count += 1
            return "BITTER FAILURE"

        soup = self.soup("")
        cdata = CData("<><><>")
        soup.insert(1, cdata)
        self.assertEqual(
            b"<![CDATA[<><><>]]>", soup.encode(formatter=increment))
        self.assertEqual(1, self.count)

    def test_doctype_ends_in_newline(self):
        # Unlike other NavigableString subclasses, a DOCTYPE always ends
        # in a newline.
        doctype = Doctype("foo")
        soup = self.soup("")
        soup.insert(1, doctype)
        self.assertEqual(soup.encode(), b"<!DOCTYPE foo>\n")


class TestSoupSelector(TreeTest):

    HTML = """
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>The title</title>
<link rel="stylesheet" href="blah.css" type="text/css" id="l1">
</head>
<body>

<div id="main" class="fancy">
<div id="inner">
<h1 id="header1">An H1</h1>
<p>Some text</p>
<p class="onep" id="p1">Some more text</p>
<h2 id="header2">An H2</h2>
<p class="class1 class2 class3" id="pmulti">Another</p>
<a href="http://bob.example.org/" rel="friend met" id="bob">Bob</a>
<h2 id="header3">Another H2</h2>
<a id="me" href="http://simonwillison.net/" rel="me">me</a>
<span class="s1">
<a href="#" id="s1a1">span1a1</a>
<a href="#" id="s1a2">span1a2 <span id="s1a2s1">test</span></a>
<span class="span2">
<a href="#" id="s2a1">span2a1</a>
</span>
<span class="span3"></span>
</span>
</div>
<p lang="en" id="lang-en">English</p>
<p lang="en-gb" id="lang-en-gb">English UK</p>
<p lang="en-us" id="lang-en-us">English US</p>
<p lang="fr" id="lang-fr">French</p>
</div>

<div id="footer">
</div>
"""

    def setUp(self):
        self.soup = BeautifulSoup(self.HTML)

    def assertSelects(self, selector, expected_ids):
        el_ids = [el['id'] for el in self.soup.select(selector)]
        el_ids.sort()
        expected_ids.sort()
        self.assertEqual(expected_ids, el_ids,
            "Selector %s, expected [%s], got [%s]" % (
                selector, ', '.join(expected_ids), ', '.join(el_ids)
            )
        )

    assertSelect = assertSelects

    def assertSelectMultiple(self, *tests):
        for selector, expected_ids in tests:
            self.assertSelect(selector, expected_ids)

    def test_one_tag_one(self):
        els = self.soup.select('title')
        self.assertEqual(len(els), 1)
        self.assertEqual(els[0].name, 'title')
        self.assertEqual(els[0].contents, [u'The title'])

    def test_one_tag_many(self):
        els = self.soup.select('div')
        self.assertEqual(len(els), 3)
        for div in els:
            self.assertEqual(div.name, 'div')

    def test_tag_in_tag_one(self):
        els = self.soup.select('div div')
        self.assertSelects('div div', ['inner'])

    def test_tag_in_tag_many(self):
        for selector in ('html div', 'html body div', 'body div'):
            self.assertSelects(selector, ['main', 'inner', 'footer'])

    def test_tag_no_match(self):
        self.assertEqual(len(self.soup.select('del')), 0)

    def test_invalid_tag(self):
        self.assertRaises(ValueError, self.soup.select, 'tag%t')

    def test_header_tags(self):
        self.assertSelectMultiple(
            ('h1', ['header1']),
            ('h2', ['header2', 'header3']),
        )

    def test_class_one(self):
        for selector in ('.onep', 'p.onep', 'html p.onep'):
            els = self.soup.select(selector)
            self.assertEqual(len(els), 1)
            self.assertEqual(els[0].name, 'p')
            self.assertEqual(els[0]['class'], ['onep'])

    def test_class_mismatched_tag(self):
        els = self.soup.select('div.onep')
        self.assertEqual(len(els), 0)

    def test_one_id(self):
        for selector in ('div#inner', '#inner', 'div div#inner'):
            self.assertSelects(selector, ['inner'])

    def test_bad_id(self):
        els = self.soup.select('#doesnotexist')
        self.assertEqual(len(els), 0)

    def test_items_in_id(self):
        els = self.soup.select('div#inner p')
        self.assertEqual(len(els), 3)
        for el in els:
            self.assertEqual(el.name, 'p')
        self.assertEqual(els[1]['class'], ['onep'])
        self.assertFalse(els[0].has_attr('class'))

    def test_a_bunch_of_emptys(self):
        for selector in ('div#main del', 'div#main div.oops', 'div div#main'):
            self.assertEqual(len(self.soup.select(selector)), 0)

    def test_multi_class_support(self):
        for selector in ('.class1', 'p.class1', '.class2', 'p.class2',
            '.class3', 'p.class3', 'html p.class2', 'div#inner .class2'):
            self.assertSelects(selector, ['pmulti'])

    def test_multi_class_selection(self):
        for selector in ('.class1.class3', '.class3.class2',
                         '.class1.class2.class3'):
            self.assertSelects(selector, ['pmulti'])

    def test_child_selector(self):
        self.assertSelects('.s1 > a', ['s1a1', 's1a2'])
        self.assertSelects('.s1 > a span', ['s1a2s1'])

    def test_child_selector_id(self):
        self.assertSelects('.s1 > a#s1a2 span', ['s1a2s1'])

    def test_attribute_equals(self):
        self.assertSelectMultiple(
            ('p[class="onep"]', ['p1']),
            ('p[id="p1"]', ['p1']),
            ('[class="onep"]', ['p1']),
            ('[id="p1"]', ['p1']),
            ('link[rel="stylesheet"]', ['l1']),
            ('link[type="text/css"]', ['l1']),
            ('link[href="blah.css"]', ['l1']),
            ('link[href="no-blah.css"]', []),
            ('[rel="stylesheet"]', ['l1']),
            ('[type="text/css"]', ['l1']),
            ('[href="blah.css"]', ['l1']),
            ('[href="no-blah.css"]', []),
            ('p[href="no-blah.css"]', []),
            ('[href="no-blah.css"]', []),
        )

    def test_attribute_tilde(self):
        self.assertSelectMultiple(
            ('p[class~="class1"]', ['pmulti']),
            ('p[class~="class2"]', ['pmulti']),
            ('p[class~="class3"]', ['pmulti']),
            ('[class~="class1"]', ['pmulti']),
            ('[class~="class2"]', ['pmulti']),
            ('[class~="class3"]', ['pmulti']),
            ('a[rel~="friend"]', ['bob']),
            ('a[rel~="met"]', ['bob']),
            ('[rel~="friend"]', ['bob']),
            ('[rel~="met"]', ['bob']),
        )

    def test_attribute_startswith(self):
        self.assertSelectMultiple(
            ('[rel^="style"]', ['l1']),
            ('link[rel^="style"]', ['l1']),
            ('notlink[rel^="notstyle"]', []),
            ('[rel^="notstyle"]', []),
            ('link[rel^="notstyle"]', []),
            ('link[href^="bla"]', ['l1']),
            ('a[href^="http://"]', ['bob', 'me']),
            ('[href^="http://"]', ['bob', 'me']),
            ('[id^="p"]', ['pmulti', 'p1']),
            ('[id^="m"]', ['me', 'main']),
            ('div[id^="m"]', ['main']),
            ('a[id^="m"]', ['me']),
        )

    def test_attribute_endswith(self):
        self.assertSelectMultiple(
            ('[href$=".css"]', ['l1']),
            ('link[href$=".css"]', ['l1']),
            ('link[id$="1"]', ['l1']),
            ('[id$="1"]', ['l1', 'p1', 'header1', 's1a1', 's2a1', 's1a2s1']),
            ('div[id$="1"]', []),
            ('[id$="noending"]', []),
        )

    def test_attribute_contains(self):
        self.assertSelectMultiple(
            # From test_attribute_startswith
            ('[rel*="style"]', ['l1']),
            ('link[rel*="style"]', ['l1']),
            ('notlink[rel*="notstyle"]', []),
            ('[rel*="notstyle"]', []),
            ('link[rel*="notstyle"]', []),
            ('link[href*="bla"]', ['l1']),
            ('a[href*="http://"]', ['bob', 'me']),
            ('[href*="http://"]', ['bob', 'me']),
            ('[id*="p"]', ['pmulti', 'p1']),
            ('div[id*="m"]', ['main']),
            ('a[id*="m"]', ['me']),
            # From test_attribute_endswith
            ('[href*=".css"]', ['l1']),
            ('link[href*=".css"]', ['l1']),
            ('link[id*="1"]', ['l1']),
            ('[id*="1"]', ['l1', 'p1', 'header1', 's1a1', 's1a2', 's2a1', 's1a2s1']),
            ('div[id*="1"]', []),
            ('[id*="noending"]', []),
            # New for this test
            ('[href*="."]', ['bob', 'me', 'l1']),
            ('a[href*="."]', ['bob', 'me']),
            ('link[href*="."]', ['l1']),
            ('div[id*="n"]', ['main', 'inner']),
            ('div[id*="nn"]', ['inner']),
        )

    def test_attribute_exact_or_hypen(self):
        self.assertSelectMultiple(
            ('p[lang|="en"]', ['lang-en', 'lang-en-gb', 'lang-en-us']),
            ('[lang|="en"]', ['lang-en', 'lang-en-gb', 'lang-en-us']),
            ('p[lang|="fr"]', ['lang-fr']),
            ('p[lang|="gb"]', []),
        )

    def test_attribute_exists(self):
        self.assertSelectMultiple(
            ('[rel]', ['l1', 'bob', 'me']),
            ('link[rel]', ['l1']),
            ('a[rel]', ['bob', 'me']),
            ('[lang]', ['lang-en', 'lang-en-gb', 'lang-en-us', 'lang-fr']),
            ('p[class]', ['p1', 'pmulti']),
            ('[blah]', []),
            ('p[blah]', []),
        )

    def test_nth_of_type(self):
        # Try to select first paragraph
        els = self.soup.select('div#inner p:nth-of-type(1)')
        self.assertEqual(len(els), 1)
        self.assertEqual(els[0].string, u'Some text')

        # Try to select third paragraph
        els = self.soup.select('div#inner p:nth-of-type(3)')
        self.assertEqual(len(els), 1)
        self.assertEqual(els[0].string, u'Another')

        # Try to select (non-existent!) fourth paragraph
        els = self.soup.select('div#inner p:nth-of-type(4)')
        self.assertEqual(len(els), 0)

        # Pass in an invalid value.
        self.assertRaises(
            ValueError, self.soup.select, 'div p:nth-of-type(0)')

    def test_nth_of_type_direct_descendant(self):
        els = self.soup.select('div#inner > p:nth-of-type(1)')
        self.assertEqual(len(els), 1)
        self.assertEqual(els[0].string, u'Some text')

    def test_id_child_selector_nth_of_type(self):
        self.assertSelects('#inner > p:nth-of-type(2)', ['p1'])

    def test_select_on_element(self):
        # Other tests operate on the tree; this operates on an element
        # within the tree.
        inner = self.soup.find("div", id="main")
        selected = inner.select("div")
        # The <div id="inner"> tag was selected. The <div id="footer">
        # tag was not.
        self.assertSelectsIDs(selected, ['inner'])

    def test_overspecified_child_id(self):
        self.assertSelects(".fancy #inner", ['inner'])
        self.assertSelects(".normal #inner", [])

    def test_adjacent_sibling_selector(self):
        self.assertSelects('#p1 + h2', ['header2'])
        self.assertSelects('#p1 + h2 + p', ['pmulti'])
        self.assertSelects('#p1 + #header2 + .class1', ['pmulti'])
        self.assertEqual([], self.soup.select('#p1 + p'))

    def test_general_sibling_selector(self):
        self.assertSelects('#p1 ~ h2', ['header2', 'header3'])
        self.assertSelects('#p1 ~ #header2', ['header2'])
        self.assertSelects('#p1 ~ h2 + a', ['me'])
        self.assertSelects('#p1 ~ h2 + [rel="me"]', ['me'])
        self.assertEqual([], self.soup.select('#inner ~ h2'))

    def test_dangling_combinator(self):
        self.assertRaises(ValueError, self.soup.select, 'h1 >')

    def test_sibling_combinator_wont_select_same_tag_twice(self):
        self.assertSelects('p[lang] ~ p', ['lang-en-gb', 'lang-en-us', 'lang-fr'])