Move the Soup Sieve proxy and its tests into separate files.

5 files changed, 723 insertions, 688 deletions

diff --git a/bs4/__init__.py b/bs4/__init__.py
index db71cc7..a5128d2 100644
--- a/bs4/__init__.py
+++ b/bs4/__init__.py
@@ -43,6 +43,7 @@ from .dammit import UnicodeDammit
 from .element import (
     CData,
     Comment,
+    CSS,
     DEFAULT_OUTPUT_ENCODING,
     Declaration,
     Doctype,
diff --git a/bs4/css.py b/bs4/css.py
new file mode 100644
index 0000000..5d60267
--- /dev/null
+++ b/bs4/css.py
@@ -0,0 +1,251 @@
+"""Integration code for CSS selectors using Soup Sieve (pypi: soupsieve)."""
+
+try:
+    import soupsieve
+except ImportError as e:
+    soupsieve = None
+    warnings.warn(
+        'The soupsieve package is not installed. CSS selectors cannot be used.'
+    )
+
+    
+class CSS(object):
+    """A proxy object against the soupsieve library, to simplify its
+    CSS selector API.
+
+    Acquire this object through the .css attribute on the
+    BeautifulSoup object, or on the Tag you want to use as the
+    starting point for a CSS selector.
+
+    Specifically, the element to be selected against doesn't need to
+    be explicitly specified in the function call, since you access
+    this object through a specific tag.
+
+    """
+
+    def __init__(self, tag):
+        """Constructor.
+
+        You don't need to instantiate this class yourself; instead,
+        access the .css attribute on the BeautifulSoup object, or on
+        the Tag you want to use as the starting point for your CSS
+        selector.
+
+        :param tag: All CSS selectors will use this as their starting
+        point.
+
+        """
+        if soupsieve is None:
+            raise NotImplementedError(
+                "Cannot execute CSS selectors because the soupsieve package is not installed."
+            )
+        self.tag = tag
+
+    @classmethod
+    def escape(cls, ident):
+        """Escape a CSS selector.
+
+        This is a simple wrapper around soupselect.escape().
+        """
+        if soupsieve is None:
+            raise NotImplementedError(
+                "Cannot escape CSS selectors because the soupsieve package is not installed."
+            )
+        return soupsieve.escape(ident)
+        
+    def _ns(self, ns):
+        """Normalize a dictionary of namespaces."""
+        if ns is None:
+            ns = self.tag._namespaces
+        return ns
+
+    def _rs(self, results):
+        """Normalize a list of results to a Resultset.
+
+        A ResultSet is more consistent with the rest of Beautiful
+        Soup, and ResultSet.__getattr__ has a helpful error message if
+        you try to treat a list of results as a single result (a
+        common mistake).
+        """
+        # Import here to avoid circular import
+        from bs4.element import ResultSet
+        return ResultSet(None, results)
+
+    def select_one(self, select, namespaces=None, flags=0, **kwargs):
+        """Perform a CSS selection operation on the current Tag and return the
+        first result.
+
+        This uses the Soup Sieve library. For more information, see
+        that library's documentation for the soupsieve.select_one()
+        method.
+
+        :param selector: A CSS selector.
+
+        :param namespaces: A dictionary mapping namespace prefixes
+           used in the CSS selector to namespace URIs. By default,
+           Beautiful Soup will use the prefixes it encountered while
+           parsing the document.
+
+        :param flags: Flags to be passed into Soup Sieve's
+            soupsieve.select_one() method.
+
+        :param kwargs: Keyword arguments to be passed into SoupSieve's
+           soupsieve.select_one() method.
+
+        :return: A Tag, or None if the selector has no match.
+        :rtype: bs4.element.Tag
+
+        """
+        return soupsieve.select_one(
+            select, self.tag, self._ns(namespaces), flags, **kwargs
+        )
+
+    def select(self, select, namespaces=None, limit=0, flags=0, **kwargs):
+        """Perform a CSS selection operation on the current Tag.
+
+        This uses the Soup Sieve library. For more information, see
+        that library's documentation for the soupsieve.select()
+        method.
+
+        :param selector: A string containing a CSS selector.
+
+        :param namespaces: A dictionary mapping namespace prefixes
+            used in the CSS selector to namespace URIs. By default,
+            Beautiful Soup will pass in the prefixes it encountered while
+            parsing the document.
+
+        :param limit: After finding this number of results, stop looking.
+
+        :param flags: Flags to be passed into Soup Sieve's
+            soupsieve.select() method.
+
+        :param kwargs: Keyword arguments to be passed into SoupSieve's
+            soupsieve.select() method.
+
+        :return: A ResultSet of Tag objects.
+        :rtype: bs4.element.ResultSet
+
+        """
+        if limit is None:
+            limit = 0
+
+        return self._rs(
+            soupsieve.select(
+                select, self.tag, self._ns(namespaces), limit, flags,
+                **kwargs
+            )
+        )
+
+    def iselect(self, select, namespaces=None, limit=0, flags=0, **kwargs):
+        """Perform a CSS selection operation on the current Tag.
+
+        This uses the Soup Sieve library. For more information, see
+        that library's documentation for the soupsieve.iselect()
+        method. It is the same as select(), but it returns a generator
+        instead of a list.
+
+        :param selector: A string containing a CSS selector.
+
+        :param namespaces: A dictionary mapping namespace prefixes
+            used in the CSS selector to namespace URIs. By default,
+            Beautiful Soup will pass in the prefixes it encountered while
+            parsing the document.
+
+        :param limit: After finding this number of results, stop looking.
+
+        :param flags: Flags to be passed into Soup Sieve's
+            soupsieve.iselect() method.
+
+        :param kwargs: Keyword arguments to be passed into SoupSieve's
+            soupsieve.iselect() method.
+
+        :return: A generator
+        :rtype: types.GeneratorType
+        """
+        return soupsieve.iselect(
+            select, self.tag, self._ns(namespaces), limit, flags, **kwargs
+        )
+
+    def closest(self, select, namespaces=None, flags=0, **kwargs):
+        """Find the Tag closest to this one that matches the given selector.
+
+        This uses the Soup Sieve library. For more information, see
+        that library's documentation for the soupsieve.closest()
+        method.
+
+        :param selector: A string containing a CSS selector.
+
+        :param namespaces: A dictionary mapping namespace prefixes
+            used in the CSS selector to namespace URIs. By default,
+            Beautiful Soup will pass in the prefixes it encountered while
+            parsing the document.
+
+        :param flags: Flags to be passed into Soup Sieve's
+            soupsieve.closest() method.
+
+        :param kwargs: Keyword arguments to be passed into SoupSieve's
+            soupsieve.closest() method.
+
+        :return: A Tag, or None if there is no match.
+        :rtype: bs4.Tag
+
+        """
+        return soupsieve.closest(
+            select, self.tag, self._ns(namespaces), flags, **kwargs
+        )
+
+    def match(self, select, namespaces=None, flags=0, **kwargs):
+        """Check whether this Tag matches the given CSS selector.
+
+        This uses the Soup Sieve library. For more information, see
+        that library's documentation for the soupsieve.match()
+        method.
+
+        :param: a CSS selector.
+
+        :param namespaces: A dictionary mapping namespace prefixes
+            used in the CSS selector to namespace URIs. By default,
+            Beautiful Soup will pass in the prefixes it encountered while
+            parsing the document.
+
+        :param flags: Flags to be passed into Soup Sieve's
+            soupsieve.match() method.
+
+        :param kwargs: Keyword arguments to be passed into SoupSieve's
+            soupsieve.match() method.
+
+        :return: True if this Tag matches the selector; False otherwise.
+        :rtype: bool
+        """
+        return soupsieve.match(
+            select, self.tag, self._ns(namespaces), flags, **kwargs
+        )
+
+    def filter(self, select, namespaces=None, flags=0, **kwargs):
+        """Filter this Tag's direct children based on the given CSS selector.
+
+        This uses the Soup Sieve library. It works the same way as
+        passing this Tag into that library's soupsieve.filter()
+        method. More information, for more information see the
+        documentation for soupsieve.filter().
+
+        :param namespaces: A dictionary mapping namespace prefixes
+            used in the CSS selector to namespace URIs. By default,
+            Beautiful Soup will pass in the prefixes it encountered while
+            parsing the document.
+
+        :param flags: Flags to be passed into Soup Sieve's
+            soupsieve.filter() method.
+
+        :param kwargs: Keyword arguments to be passed into SoupSieve's
+            soupsieve.filter() method.
+
+        :return: A ResultSet of Tag objects.
+        :rtype: bs4.element.ResultSet
+
+        """
+        return self._rs(
+            soupsieve.filter(
+                select, self.tag, self._ns(namespaces), flags, **kwargs
+            )
+        )
diff --git a/bs4/element.py b/bs4/element.py
index a96593c..619fb73 100644
--- a/bs4/element.py
+++ b/bs4/element.py
@@ -8,14 +8,8 @@ except ImportError as e:
 import re
 import sys
 import warnings
-try:
-    import soupsieve
-except ImportError as e:
-    soupsieve = None
-    warnings.warn(
-        'The soupsieve package is not installed. CSS selectors cannot be used.'
-    )
 
+from bs4.css import CSS
 from bs4.formatter import (
     Formatter,
     HTMLFormatter,
@@ -1948,7 +1942,7 @@ class Tag(PageElement):
            Beautiful Soup will use the prefixes it encountered while
            parsing the document.
 
-        :param kwargs: Keyword arguments to be passed into SoupSieve's
+        :param kwargs: Keyword arguments to be passed into Soup Sieve's
            soupsieve.select() method.
 
         :return: A Tag.
@@ -1981,7 +1975,7 @@ class Tag(PageElement):
     @property
     def css(self):
         """Return an interface to the CSS selector API."""
-        return SoupSieveProxy(self)
+        return CSS(self)
 
     # Old names for backwards compatibility
     def childGenerator(self):
@@ -2296,224 +2290,3 @@ class ResultSet(list):
         raise AttributeError(
             "ResultSet object has no attribute '%s'. You're probably treating a list of elements like a single element. Did you call find_all() when you meant to call find()?" % key
         )
-
-class SoupSieveProxy(object):
-    """A proxy object against the soupsieve library, to simplify its
-    CSS selector API.
-
-    Specifically, the element to be selected against doesn't need to
-    be explicitly specified in the function call, since you access
-    this object through a specific tag.
-    """
-
-    def __init__(self, tag):
-        """Constructor.
-
-        You don't need to instantiate this class yourself; instead,
-        access the .css attribute on the Tag you want to use as the
-        starting point for your CSS selector, or on the BeautifulSoup
-        object itself.
-
-        :param tag: All CSS selectors will use this as their starting
-        point.
-        """
-        if soupsieve is None:
-            raise NotImplementedError(
-                "Cannot execute CSS selectors because the soupsieve package is not installed."
-            )
-        self.tag = tag
-
-    def _ns(self, ns):
-        """Normalize a dictionary of namespaces."""
-        if ns is None:
-            ns = self.tag._namespaces
-        return ns
-
-    def _rs(self, results):
-        """Normalize a list of results to a Resultset.
-
-        A ResultSet is more consistent with the rest of Beautiful
-        Soup, and ResultSet.__getattr__ has a helpful error message if
-        you try to treat a list of results as a single result (a
-        common mistake).
-        """
-        return ResultSet(None, results)
-
-    def select_one(self, select, namespaces=None, flags=0, **kwargs):
-        """Perform a CSS selection operation on the current Tag and return the
-        first result.
-
-        This uses the Soup Sieve library. For more information, see
-        that library's documentation for the soupsieve.select_one()
-        method.
-
-        :param selector: A CSS selector.
-
-        :param namespaces: A dictionary mapping namespace prefixes
-           used in the CSS selector to namespace URIs. By default,
-           Beautiful Soup will use the prefixes it encountered while
-           parsing the document.
-
-        :param flags: Flags to be passed into Soup Sieve's
-            soupsieve.select_one() method.
-
-        :param kwargs: Keyword arguments to be passed into SoupSieve's
-           soupsieve.select_one() method.
-
-        :return: A Tag, or None if the selector has no match.
-        :rtype: bs4.element.Tag
-
-        """
-        return soupsieve.select_one(
-            select, self.tag, self._ns(namespaces), flags, **kwargs
-        )
-
-    def select(self, select, namespaces=None, limit=0, flags=0, **kwargs):
-        """Perform a CSS selection operation on the current Tag.
-
-        This uses the Soup Sieve library. For more information, see
-        that library's documentation for the soupsieve.select()
-        method.
-
-        :param selector: A string containing a CSS selector.
-
-        :param namespaces: A dictionary mapping namespace prefixes
-            used in the CSS selector to namespace URIs. By default,
-            Beautiful Soup will pass in the prefixes it encountered while
-            parsing the document.
-
-        :param limit: After finding this number of results, stop looking.
-
-        :param flags: Flags to be passed into Soup Sieve's
-            soupsieve.select() method.
-
-        :param kwargs: Keyword arguments to be passed into SoupSieve's
-            soupsieve.select() method.
-
-        :return: A ResultSet of Tag objects.
-        :rtype: bs4.element.ResultSet
-
-        """
-        if limit is None:
-            limit = 0
-
-        return self._rs(
-            soupsieve.select(
-                select, self.tag, self._ns(namespaces), limit, flags,
-                **kwargs
-            )
-        )
-
-    def iselect(self, select, namespaces=None, limit=0, flags=0, **kwargs):
-        """Perform a CSS selection operation on the current Tag.
-
-        This uses the Soup Sieve library. For more information, see
-        that library's documentation for the soupsieve.iselect()
-        method. It is the same as select(), but it returns a generator
-        instead of a list.
-
-        :param selector: A string containing a CSS selector.
-
-        :param namespaces: A dictionary mapping namespace prefixes
-            used in the CSS selector to namespace URIs. By default,
-            Beautiful Soup will pass in the prefixes it encountered while
-            parsing the document.
-
-        :param limit: After finding this number of results, stop looking.
-
-        :param flags: Flags to be passed into Soup Sieve's
-            soupsieve.iselect() method.
-
-        :param kwargs: Keyword arguments to be passed into SoupSieve's
-            soupsieve.iselect() method.
-
-        :return: A generator
-        :rtype: types.GeneratorType
-        """
-        return soupsieve.iselect(
-            select, self.tag, self._ns(namespaces), limit, flags, **kwargs
-        )
-
-    def closest(self, select, namespaces=None, flags=0, **kwargs):
-        """Find the Tag closest to this one that matches the given selector.
-
-        This uses the Soup Sieve library. For more information, see
-        that library's documentation for the soupsieve.closest()
-        method.
-
-        :param selector: A string containing a CSS selector.
-
-        :param namespaces: A dictionary mapping namespace prefixes
-            used in the CSS selector to namespace URIs. By default,
-            Beautiful Soup will pass in the prefixes it encountered while
-            parsing the document.
-
-        :param flags: Flags to be passed into Soup Sieve's
-            soupsieve.closest() method.
-
-        :param kwargs: Keyword arguments to be passed into SoupSieve's
-            soupsieve.closest() method.
-
-        :return: A Tag, or None if there is no match.
-        :rtype: bs4.Tag
-
-        """
-        return soupsieve.closest(
-            select, self.tag, self._ns(namespaces), flags, **kwargs
-        )
-
-    def match(self, select, namespaces=None, flags=0, **kwargs):
-        """Check whether this Tag matches the given CSS selector.
-
-        This uses the Soup Sieve library. For more information, see
-        that library's documentation for the soupsieve.match()
-        method.
-
-        :param: a CSS selector.
-
-        :param namespaces: A dictionary mapping namespace prefixes
-            used in the CSS selector to namespace URIs. By default,
-            Beautiful Soup will pass in the prefixes it encountered while
-            parsing the document.
-
-        :param flags: Flags to be passed into Soup Sieve's
-            soupsieve.match() method.
-
-        :param kwargs: Keyword arguments to be passed into SoupSieve's
-            soupsieve.match() method.
-
-        :return: True if this Tag matches the selector; False otherwise.
-        :rtype: bool
-        """
-        return soupsieve.match(
-            select, self.tag, self._ns(namespaces), flags, **kwargs
-        )
-
-    def filter(self, select, namespaces=None, flags=0, **kwargs):
-        """Filter this Tag's direct children based on the given CSS selector.
-
-        This uses the Soup Sieve library. It works the same way as
-        passing this Tag into that library's soupsieve.filter()
-        method. More information, for more information see the
-        documentation for soupsieve.filter().
-
-        :param namespaces: A dictionary mapping namespace prefixes
-            used in the CSS selector to namespace URIs. By default,
-            Beautiful Soup will pass in the prefixes it encountered while
-            parsing the document.
-
-        :param flags: Flags to be passed into Soup Sieve's
-            soupsieve.filter() method.
-
-        :param kwargs: Keyword arguments to be passed into SoupSieve's
-            soupsieve.filter() method.
-
-        :return: A ResultSet of Tag objects.
-        :rtype: bs4.element.ResultSet
-
-        """
-        return self._rs(
-            soupsieve.filter(
-                select, self.tag, self._ns(namespaces), flags, **kwargs
-            )
-        )
diff --git a/bs4/tests/test_css.py b/bs4/tests/test_css.py
new file mode 100644
index 0000000..3da9aed
--- /dev/null
+++ b/bs4/tests/test_css.py
@@ -0,0 +1,468 @@
+import pytest
+import types
+
+from bs4 import (
+    BeautifulSoup,
+    ResultSet,
+)
+
+from . import (
+    SoupTest,
+    SOUP_SIEVE_PRESENT,
+)
+
+if SOUP_SIEVE_PRESENT:
+    from soupsieve import SelectorSyntaxError
+
+
+@pytest.mark.skipif(not SOUP_SIEVE_PRESENT, reason="Soup Sieve not installed")
+class TestCSSSelectors(SoupTest):
+    """Test basic CSS selector functionality.
+
+    This functionality is implemented in soupsieve, which has a much
+    more comprehensive test suite, so this is basically an extra check
+    that soupsieve works as expected.
+    """
+
+    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>
+<custom-dashed-tag class="dashed" id="dash1">Hello there.</custom-dashed-tag>
+<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>
+<custom-dashed-tag class="dashed" id="dash2"/>
+<div data-tag="dashedvalue" id="data1"/>
+</span>
+</div>
+<x id="xid">
+<z id="zida"/>
+<z id="zidab"/>
+<z id="zidac"/>
+</x>
+<y id="yid">
+<z id="zidb"/>
+</y>
+<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_method(self):
+        self.soup = BeautifulSoup(self.HTML, 'html.parser')
+
+    def assert_selects(self, selector, expected_ids, **kwargs):
+        results = self.soup.select(selector, **kwargs)
+        assert isinstance(results, ResultSet)
+        el_ids = [el['id'] for el in results]
+        el_ids.sort()
+        expected_ids.sort()
+        assert expected_ids == el_ids, "Selector %s, expected [%s], got [%s]" % (
+                selector, ', '.join(expected_ids), ', '.join(el_ids)
+        )
+
+    assertSelect = assert_selects
+
+    def assert_select_multiple(self, *tests):
+        for selector, expected_ids in tests:
+            self.assert_selects(selector, expected_ids)
+
+    def test_one_tag_one(self):
+        els = self.soup.select('title')
+        assert len(els) == 1
+        assert els[0].name == 'title'
+        assert els[0].contents == ['The title']
+
+    def test_one_tag_many(self):
+        els = self.soup.select('div')
+        assert len(els) == 4
+        for div in els:
+            assert div.name == 'div'
+
+        el = self.soup.select_one('div')
+        assert 'main' == el['id']
+
+    def test_select_one_returns_none_if_no_match(self):
+        match = self.soup.select_one('nonexistenttag')
+        assert None == match
+
+
+    def test_tag_in_tag_one(self):
+        els = self.soup.select('div div')
+        self.assert_selects('div div', ['inner', 'data1'])
+
+    def test_tag_in_tag_many(self):
+        for selector in ('html div', 'html body div', 'body div'):
+            self.assert_selects(selector, ['data1', 'main', 'inner', 'footer'])
+
+
+    def test_limit(self):
+        self.assert_selects('html div', ['main'], limit=1)
+        self.assert_selects('html body div', ['inner', 'main'], limit=2)
+        self.assert_selects('body div', ['data1', 'main', 'inner', 'footer'],
+                           limit=10)
+
+    def test_tag_no_match(self):
+        assert len(self.soup.select('del')) == 0
+
+    def test_invalid_tag(self):
+        with pytest.raises(SelectorSyntaxError):
+            self.soup.select('tag%t')
+
+    def test_select_dashed_tag_ids(self):
+        self.assert_selects('custom-dashed-tag', ['dash1', 'dash2'])
+
+    def test_select_dashed_by_id(self):
+        dashed = self.soup.select('custom-dashed-tag[id=\"dash2\"]')
+        assert dashed[0].name == 'custom-dashed-tag'
+        assert dashed[0]['id'] == 'dash2'
+
+    def test_dashed_tag_text(self):
+        assert self.soup.select('body > custom-dashed-tag')[0].text == 'Hello there.'
+
+    def test_select_dashed_matches_find_all(self):
+        assert self.soup.select('custom-dashed-tag') == self.soup.find_all('custom-dashed-tag')
+
+    def test_header_tags(self):
+        self.assert_select_multiple(
+            ('h1', ['header1']),
+            ('h2', ['header2', 'header3']),
+        )
+
+    def test_class_one(self):
+        for selector in ('.onep', 'p.onep', 'html p.onep'):
+            els = self.soup.select(selector)
+            assert len(els) == 1
+            assert els[0].name == 'p'
+            assert els[0]['class'] == ['onep']
+
+    def test_class_mismatched_tag(self):
+        els = self.soup.select('div.onep')
+        assert len(els) == 0
+
+    def test_one_id(self):
+        for selector in ('div#inner', '#inner', 'div div#inner'):
+            self.assert_selects(selector, ['inner'])
+
+    def test_bad_id(self):
+        els = self.soup.select('#doesnotexist')
+        assert len(els) == 0
+
+    def test_items_in_id(self):
+        els = self.soup.select('div#inner p')
+        assert len(els) == 3
+        for el in els:
+            assert el.name == 'p'
+        assert els[1]['class'] == ['onep']
+        assert not 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'):
+            assert 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.assert_selects(selector, ['pmulti'])
+
+    def test_multi_class_selection(self):
+        for selector in ('.class1.class3', '.class3.class2',
+                         '.class1.class2.class3'):
+            self.assert_selects(selector, ['pmulti'])
+
+    def test_child_selector(self):
+        self.assert_selects('.s1 > a', ['s1a1', 's1a2'])
+        self.assert_selects('.s1 > a span', ['s1a2s1'])
+
+    def test_child_selector_id(self):
+        self.assert_selects('.s1 > a#s1a2 span', ['s1a2s1'])
+
+    def test_attribute_equals(self):
+        self.assert_select_multiple(
+            ('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.assert_select_multiple(
+            ('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.assert_select_multiple(
+            ('[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']),
+            ('div[data-tag^="dashed"]', ['data1'])
+        )
+
+    def test_attribute_endswith(self):
+        self.assert_select_multiple(
+            ('[href$=".css"]', ['l1']),
+            ('link[href$=".css"]', ['l1']),
+            ('link[id$="1"]', ['l1']),
+            ('[id$="1"]', ['data1', 'l1', 'p1', 'header1', 's1a1', 's2a1', 's1a2s1', 'dash1']),
+            ('div[id$="1"]', ['data1']),
+            ('[id$="noending"]', []),
+        )
+
+    def test_attribute_contains(self):
+        self.assert_select_multiple(
+            # From test_attribute_startswith
+            ('[rel*="style"]', ['l1']),
+            ('link[rel*="style"]', ['l1']),
+            ('notlink[rel*="notstyle"]', []),
+            ('[rel*="notstyle"]', []),
+            ('link[rel*="notstyle"]', []),
+            ('link[href*="bla"]', ['l1']),
+            ('[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"]', ['data1', 'l1', 'p1', 'header1', 's1a1', 's1a2', 's2a1', 's1a2s1', 'dash1']),
+            ('div[id*="1"]', ['data1']),
+            ('[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']),
+            ('div[data-tag*="edval"]', ['data1'])
+        )
+
+    def test_attribute_exact_or_hypen(self):
+        self.assert_select_multiple(
+            ('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.assert_select_multiple(
+            ('[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]', []),
+            ('div[data-tag]', ['data1'])
+        )
+
+    def test_quoted_space_in_selector_name(self):
+        html = """<div style="display: wrong">nope</div>
+        <div style="display: right">yes</div>
+        """
+        soup = BeautifulSoup(html, 'html.parser')
+        [chosen] = soup.select('div[style="display: right"]')
+        assert "yes" == chosen.string
+
+    def test_unsupported_pseudoclass(self):
+        with pytest.raises(NotImplementedError):
+            self.soup.select("a:no-such-pseudoclass")
+
+        with pytest.raises(SelectorSyntaxError):
+            self.soup.select("a:nth-of-type(a)")
+
+    def test_nth_of_type(self):
+        # Try to select first paragraph
+        els = self.soup.select('div#inner p:nth-of-type(1)')
+        assert len(els) == 1
+        assert els[0].string == 'Some text'
+
+        # Try to select third paragraph
+        els = self.soup.select('div#inner p:nth-of-type(3)')
+        assert len(els) == 1
+        assert els[0].string == 'Another'
+
+        # Try to select (non-existent!) fourth paragraph
+        els = self.soup.select('div#inner p:nth-of-type(4)')
+        assert len(els) == 0
+
+        # Zero will select no tags.
+        els = self.soup.select('div p:nth-of-type(0)')
+        assert len(els) == 0
+
+    def test_nth_of_type_direct_descendant(self):
+        els = self.soup.select('div#inner > p:nth-of-type(1)')
+        assert len(els) == 1
+        assert els[0].string == 'Some text'
+
+    def test_id_child_selector_nth_of_type(self):
+        self.assert_selects('#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.assert_selects_ids(selected, ['inner', 'data1'])
+
+    def test_overspecified_child_id(self):
+        self.assert_selects(".fancy #inner", ['inner'])
+        self.assert_selects(".normal #inner", [])
+
+    def test_adjacent_sibling_selector(self):
+        self.assert_selects('#p1 + h2', ['header2'])
+        self.assert_selects('#p1 + h2 + p', ['pmulti'])
+        self.assert_selects('#p1 + #header2 + .class1', ['pmulti'])
+        assert [] == self.soup.select('#p1 + p')
+
+    def test_general_sibling_selector(self):
+        self.assert_selects('#p1 ~ h2', ['header2', 'header3'])
+        self.assert_selects('#p1 ~ #header2', ['header2'])
+        self.assert_selects('#p1 ~ h2 + a', ['me'])
+        self.assert_selects('#p1 ~ h2 + [rel="me"]', ['me'])
+        assert [] == self.soup.select('#inner ~ h2')
+
+    def test_dangling_combinator(self):
+        with pytest.raises(SelectorSyntaxError):
+            self.soup.select('h1 >')
+
+    def test_sibling_combinator_wont_select_same_tag_twice(self):
+        self.assert_selects('p[lang] ~ p', ['lang-en-gb', 'lang-en-us', 'lang-fr'])
+
+    # Test the selector grouping operator (the comma)
+    def test_multiple_select(self):
+        self.assert_selects('x, y', ['xid', 'yid'])
+
+    def test_multiple_select_with_no_space(self):
+        self.assert_selects('x,y', ['xid', 'yid'])
+
+    def test_multiple_select_with_more_space(self):
+        self.assert_selects('x,    y', ['xid', 'yid'])
+
+    def test_multiple_select_duplicated(self):
+        self.assert_selects('x, x', ['xid'])
+
+    def test_multiple_select_sibling(self):
+        self.assert_selects('x, y ~ p[lang=fr]', ['xid', 'lang-fr'])
+
+    def test_multiple_select_tag_and_direct_descendant(self):
+        self.assert_selects('x, y > z', ['xid', 'zidb'])
+
+    def test_multiple_select_direct_descendant_and_tags(self):
+        self.assert_selects('div > x, y, z', ['xid', 'yid', 'zida', 'zidb', 'zidab', 'zidac'])
+
+    def test_multiple_select_indirect_descendant(self):
+        self.assert_selects('div x,y,  z', ['xid', 'yid', 'zida', 'zidb', 'zidab', 'zidac'])
+
+    def test_invalid_multiple_select(self):
+        with pytest.raises(SelectorSyntaxError):
+            self.soup.select(',x, y')
+        with pytest.raises(SelectorSyntaxError):
+            self.soup.select('x,,y')
+
+    def test_multiple_select_attrs(self):
+        self.assert_selects('p[lang=en], p[lang=en-gb]', ['lang-en', 'lang-en-gb'])
+
+    def test_multiple_select_ids(self):
+        self.assert_selects('x, y > z[id=zida], z[id=zidab], z[id=zidb]', ['xid', 'zidb', 'zidab'])
+
+    def test_multiple_select_nested(self):
+        self.assert_selects('body > div > x, y > z', ['xid', 'zidb'])
+
+    def test_select_duplicate_elements(self):
+        # When markup contains duplicate elements, a multiple select
+        # will find all of them.
+        markup = '<div class="c1"/><div class="c2"/><div class="c1"/>'
+        soup = BeautifulSoup(markup, 'html.parser')
+        selected = soup.select(".c1, .c2")
+        assert 3 == len(selected)
+
+        # Verify that find_all finds the same elements, though because
+        # of an implementation detail it finds them in a different
+        # order.
+        for element in soup.find_all(class_=['c1', 'c2']):
+            assert element in selected
+
+    def test_closest(self):
+        inner = self.soup.find("div", id="inner")
+        closest = inner.css.closest("div[id=main]")
+        assert closest == self.soup.find("div", id="main")
+
+    def test_match(self):
+        inner = self.soup.find("div", id="inner")
+        main = self.soup.find("div", id="main")
+        assert inner.css.match("div[id=main]") == False
+        assert main.css.match("div[id=main]") == True
+
+    def test_iselect(self):
+        gen = self.soup.css.iselect("h2")
+        assert isinstance(gen, types.GeneratorType)
+        [header2, header3] = gen
+        assert header2['id'] == 'header2'
+        assert header3['id'] == 'header3'
+
+    def test_filter(self):
+        inner = self.soup.find("div", id="inner")
+        results = inner.css.filter("h2")
+        assert len(inner.css.filter("h2")) == 2
+
+        results = inner.css.filter("h2[id=header3]")
+        assert isinstance(results, ResultSet)
+        [result] = results
+        assert result['id'] == 'header3'
diff --git a/bs4/tests/test_pageelement.py b/bs4/tests/test_pageelement.py
index 6ce2573..a94280f 100644
--- a/bs4/tests/test_pageelement.py
+++ b/bs4/tests/test_pageelement.py
@@ -2,7 +2,6 @@
 import copy
 import pickle
 import pytest
-import types
 
 from bs4 import BeautifulSoup
 from bs4.element import (
@@ -12,12 +11,8 @@ from bs4.element import (
 )
 from . import (
     SoupTest,
-    SOUP_SIEVE_PRESENT,
 )
 
-if SOUP_SIEVE_PRESENT:
-    from soupsieve import SelectorSyntaxError
-
 class TestEncoding(SoupTest):
     """Test the ability to encode objects into strings."""
 
@@ -218,459 +213,6 @@ class TestFormatters(SoupTest):
         assert soup.contents[0].name == 'pre'
 
 
-@pytest.mark.skipif(not SOUP_SIEVE_PRESENT, reason="Soup Sieve not installed")
-class TestCSSSelectors(SoupTest):
-    """Test basic CSS selector functionality.
-
-    This functionality is implemented in soupsieve, which has a much
-    more comprehensive test suite, so this is basically an extra check
-    that soupsieve works as expected.
-    """
-
-    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>
-<custom-dashed-tag class="dashed" id="dash1">Hello there.</custom-dashed-tag>
-<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>
-<custom-dashed-tag class="dashed" id="dash2"/>
-<div data-tag="dashedvalue" id="data1"/>
-</span>
-</div>
-<x id="xid">
-<z id="zida"/>
-<z id="zidab"/>
-<z id="zidac"/>
-</x>
-<y id="yid">
-<z id="zidb"/>
-</y>
-<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_method(self):
-        self.soup = BeautifulSoup(self.HTML, 'html.parser')
-
-    def assert_selects(self, selector, expected_ids, **kwargs):
-        results = self.soup.select(selector, **kwargs)
-        assert isinstance(results, ResultSet)
-        el_ids = [el['id'] for el in results]
-        el_ids.sort()
-        expected_ids.sort()
-        assert expected_ids == el_ids, "Selector %s, expected [%s], got [%s]" % (
-                selector, ', '.join(expected_ids), ', '.join(el_ids)
-        )
-
-    assertSelect = assert_selects
-
-    def assert_select_multiple(self, *tests):
-        for selector, expected_ids in tests:
-            self.assert_selects(selector, expected_ids)
-
-    def test_one_tag_one(self):
-        els = self.soup.select('title')
-        assert len(els) == 1
-        assert els[0].name == 'title'
-        assert els[0].contents == ['The title']
-
-    def test_one_tag_many(self):
-        els = self.soup.select('div')
-        assert len(els) == 4
-        for div in els:
-            assert div.name == 'div'
-
-        el = self.soup.select_one('div')
-        assert 'main' == el['id']
-
-    def test_select_one_returns_none_if_no_match(self):
-        match = self.soup.select_one('nonexistenttag')
-        assert None == match
-
-
-    def test_tag_in_tag_one(self):
-        els = self.soup.select('div div')
-        self.assert_selects('div div', ['inner', 'data1'])
-
-    def test_tag_in_tag_many(self):
-        for selector in ('html div', 'html body div', 'body div'):
-            self.assert_selects(selector, ['data1', 'main', 'inner', 'footer'])
-
-
-    def test_limit(self):
-        self.assert_selects('html div', ['main'], limit=1)
-        self.assert_selects('html body div', ['inner', 'main'], limit=2)
-        self.assert_selects('body div', ['data1', 'main', 'inner', 'footer'],
-                           limit=10)
-
-    def test_tag_no_match(self):
-        assert len(self.soup.select('del')) == 0
-
-    def test_invalid_tag(self):
-        with pytest.raises(SelectorSyntaxError):
-            self.soup.select('tag%t')
-
-    def test_select_dashed_tag_ids(self):
-        self.assert_selects('custom-dashed-tag', ['dash1', 'dash2'])
-
-    def test_select_dashed_by_id(self):
-        dashed = self.soup.select('custom-dashed-tag[id=\"dash2\"]')
-        assert dashed[0].name == 'custom-dashed-tag'
-        assert dashed[0]['id'] == 'dash2'
-
-    def test_dashed_tag_text(self):
-        assert self.soup.select('body > custom-dashed-tag')[0].text == 'Hello there.'
-
-    def test_select_dashed_matches_find_all(self):
-        assert self.soup.select('custom-dashed-tag') == self.soup.find_all('custom-dashed-tag')
-
-    def test_header_tags(self):
-        self.assert_select_multiple(
-            ('h1', ['header1']),
-            ('h2', ['header2', 'header3']),
-        )
-
-    def test_class_one(self):
-        for selector in ('.onep', 'p.onep', 'html p.onep'):
-            els = self.soup.select(selector)
-            assert len(els) == 1
-            assert els[0].name == 'p'
-            assert els[0]['class'] == ['onep']
-
-    def test_class_mismatched_tag(self):
-        els = self.soup.select('div.onep')
-        assert len(els) == 0
-
-    def test_one_id(self):
-        for selector in ('div#inner', '#inner', 'div div#inner'):
-            self.assert_selects(selector, ['inner'])
-
-    def test_bad_id(self):
-        els = self.soup.select('#doesnotexist')
-        assert len(els) == 0
-
-    def test_items_in_id(self):
-        els = self.soup.select('div#inner p')
-        assert len(els) == 3
-        for el in els:
-            assert el.name == 'p'
-        assert els[1]['class'] == ['onep']
-        assert not 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'):
-            assert 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.assert_selects(selector, ['pmulti'])
-
-    def test_multi_class_selection(self):
-        for selector in ('.class1.class3', '.class3.class2',
-                         '.class1.class2.class3'):
-            self.assert_selects(selector, ['pmulti'])
-
-    def test_child_selector(self):
-        self.assert_selects('.s1 > a', ['s1a1', 's1a2'])
-        self.assert_selects('.s1 > a span', ['s1a2s1'])
-
-    def test_child_selector_id(self):
-        self.assert_selects('.s1 > a#s1a2 span', ['s1a2s1'])
-
-    def test_attribute_equals(self):
-        self.assert_select_multiple(
-            ('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.assert_select_multiple(
-            ('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.assert_select_multiple(
-            ('[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']),
-            ('div[data-tag^="dashed"]', ['data1'])
-        )
-
-    def test_attribute_endswith(self):
-        self.assert_select_multiple(
-            ('[href$=".css"]', ['l1']),
-            ('link[href$=".css"]', ['l1']),
-            ('link[id$="1"]', ['l1']),
-            ('[id$="1"]', ['data1', 'l1', 'p1', 'header1', 's1a1', 's2a1', 's1a2s1', 'dash1']),
-            ('div[id$="1"]', ['data1']),
-            ('[id$="noending"]', []),
-        )
-
-    def test_attribute_contains(self):
-        self.assert_select_multiple(
-            # From test_attribute_startswith
-            ('[rel*="style"]', ['l1']),
-            ('link[rel*="style"]', ['l1']),
-            ('notlink[rel*="notstyle"]', []),
-            ('[rel*="notstyle"]', []),
-            ('link[rel*="notstyle"]', []),
-            ('link[href*="bla"]', ['l1']),
-            ('[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"]', ['data1', 'l1', 'p1', 'header1', 's1a1', 's1a2', 's2a1', 's1a2s1', 'dash1']),
-            ('div[id*="1"]', ['data1']),
-            ('[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']),
-            ('div[data-tag*="edval"]', ['data1'])
-        )
-
-    def test_attribute_exact_or_hypen(self):
-        self.assert_select_multiple(
-            ('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.assert_select_multiple(
-            ('[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]', []),
-            ('div[data-tag]', ['data1'])
-        )
-
-    def test_quoted_space_in_selector_name(self):
-        html = """<div style="display: wrong">nope</div>
-        <div style="display: right">yes</div>
-        """
-        soup = BeautifulSoup(html, 'html.parser')
-        [chosen] = soup.select('div[style="display: right"]')
-        assert "yes" == chosen.string
-
-    def test_unsupported_pseudoclass(self):
-        with pytest.raises(NotImplementedError):
-            self.soup.select("a:no-such-pseudoclass")
-
-        with pytest.raises(SelectorSyntaxError):
-            self.soup.select("a:nth-of-type(a)")
-
-    def test_nth_of_type(self):
-        # Try to select first paragraph
-        els = self.soup.select('div#inner p:nth-of-type(1)')
-        assert len(els) == 1
-        assert els[0].string == 'Some text'
-
-        # Try to select third paragraph
-        els = self.soup.select('div#inner p:nth-of-type(3)')
-        assert len(els) == 1
-        assert els[0].string == 'Another'
-
-        # Try to select (non-existent!) fourth paragraph
-        els = self.soup.select('div#inner p:nth-of-type(4)')
-        assert len(els) == 0
-
-        # Zero will select no tags.
-        els = self.soup.select('div p:nth-of-type(0)')
-        assert len(els) == 0
-
-    def test_nth_of_type_direct_descendant(self):
-        els = self.soup.select('div#inner > p:nth-of-type(1)')
-        assert len(els) == 1
-        assert els[0].string == 'Some text'
-
-    def test_id_child_selector_nth_of_type(self):
-        self.assert_selects('#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.assert_selects_ids(selected, ['inner', 'data1'])
-
-    def test_overspecified_child_id(self):
-        self.assert_selects(".fancy #inner", ['inner'])
-        self.assert_selects(".normal #inner", [])
-
-    def test_adjacent_sibling_selector(self):
-        self.assert_selects('#p1 + h2', ['header2'])
-        self.assert_selects('#p1 + h2 + p', ['pmulti'])
-        self.assert_selects('#p1 + #header2 + .class1', ['pmulti'])
-        assert [] == self.soup.select('#p1 + p')
-
-    def test_general_sibling_selector(self):
-        self.assert_selects('#p1 ~ h2', ['header2', 'header3'])
-        self.assert_selects('#p1 ~ #header2', ['header2'])
-        self.assert_selects('#p1 ~ h2 + a', ['me'])
-        self.assert_selects('#p1 ~ h2 + [rel="me"]', ['me'])
-        assert [] == self.soup.select('#inner ~ h2')
-
-    def test_dangling_combinator(self):
-        with pytest.raises(SelectorSyntaxError):
-            self.soup.select('h1 >')
-
-    def test_sibling_combinator_wont_select_same_tag_twice(self):
-        self.assert_selects('p[lang] ~ p', ['lang-en-gb', 'lang-en-us', 'lang-fr'])
-
-    # Test the selector grouping operator (the comma)
-    def test_multiple_select(self):
-        self.assert_selects('x, y', ['xid', 'yid'])
-
-    def test_multiple_select_with_no_space(self):
-        self.assert_selects('x,y', ['xid', 'yid'])
-
-    def test_multiple_select_with_more_space(self):
-        self.assert_selects('x,    y', ['xid', 'yid'])
-
-    def test_multiple_select_duplicated(self):
-        self.assert_selects('x, x', ['xid'])
-
-    def test_multiple_select_sibling(self):
-        self.assert_selects('x, y ~ p[lang=fr]', ['xid', 'lang-fr'])
-
-    def test_multiple_select_tag_and_direct_descendant(self):
-        self.assert_selects('x, y > z', ['xid', 'zidb'])
-
-    def test_multiple_select_direct_descendant_and_tags(self):
-        self.assert_selects('div > x, y, z', ['xid', 'yid', 'zida', 'zidb', 'zidab', 'zidac'])
-
-    def test_multiple_select_indirect_descendant(self):
-        self.assert_selects('div x,y,  z', ['xid', 'yid', 'zida', 'zidb', 'zidab', 'zidac'])
-
-    def test_invalid_multiple_select(self):
-        with pytest.raises(SelectorSyntaxError):
-            self.soup.select(',x, y')
-        with pytest.raises(SelectorSyntaxError):
-            self.soup.select('x,,y')
-
-    def test_multiple_select_attrs(self):
-        self.assert_selects('p[lang=en], p[lang=en-gb]', ['lang-en', 'lang-en-gb'])
-
-    def test_multiple_select_ids(self):
-        self.assert_selects('x, y > z[id=zida], z[id=zidab], z[id=zidb]', ['xid', 'zidb', 'zidab'])
-
-    def test_multiple_select_nested(self):
-        self.assert_selects('body > div > x, y > z', ['xid', 'zidb'])
-
-    def test_select_duplicate_elements(self):
-        # When markup contains duplicate elements, a multiple select
-        # will find all of them.
-        markup = '<div class="c1"/><div class="c2"/><div class="c1"/>'
-        soup = BeautifulSoup(markup, 'html.parser')
-        selected = soup.select(".c1, .c2")
-        assert 3 == len(selected)
-
-        # Verify that find_all finds the same elements, though because
-        # of an implementation detail it finds them in a different
-        # order.
-        for element in soup.find_all(class_=['c1', 'c2']):
-            assert element in selected
-
-    def test_closest(self):
-        inner = self.soup.find("div", id="inner")
-        closest = inner.css.closest("div[id=main]")
-        assert closest == self.soup.find("div", id="main")
-
-    def test_match(self):
-        inner = self.soup.find("div", id="inner")
-        main = self.soup.find("div", id="main")
-        assert inner.css.match("div[id=main]") == False
-        assert main.css.match("div[id=main]") == True
-
-    def test_iselect(self):
-        gen = self.soup.css.iselect("h2")
-        assert isinstance(gen, types.GeneratorType)
-        [header2, header3] = gen
-        assert header2['id'] == 'header2'
-        assert header3['id'] == 'header3'
-
-    def test_filter(self):
-        inner = self.soup.find("div", id="inner")
-        results = inner.css.filter("h2")
-        assert len(inner.css.filter("h2")) == 2
-
-        results = inner.css.filter("h2[id=header3]")
-        assert isinstance(results, ResultSet)
-        [result] = results
-        assert result['id'] == 'header3'
-
-
 class TestPersistence(SoupTest):
     "Testing features like pickle and deepcopy."