Testing the ability to include libraries with the bot

lib/bs4/tests/test_builder_registry.py

@@ -0,0 +1,141 @@
+"""Tests of the builder registry."""
+
+import unittest
+
+from bs4 import BeautifulSoup
+from bs4.builder import (
+    builder_registry as registry,
+    HTMLParserTreeBuilder,
+    TreeBuilderRegistry,
+)
+
+try:
+    from bs4.builder import HTML5TreeBuilder
+    HTML5LIB_PRESENT = True
+except ImportError:
+    HTML5LIB_PRESENT = False
+
+try:
+    from bs4.builder import (
+        LXMLTreeBuilderForXML,
+        LXMLTreeBuilder,
+        )
+    LXML_PRESENT = True
+except ImportError:
+    LXML_PRESENT = False
+
+
+class BuiltInRegistryTest(unittest.TestCase):
+    """Test the built-in registry with the default builders registered."""
+
+    def test_combination(self):
+        if LXML_PRESENT:
+            self.assertEqual(registry.lookup('fast', 'html'),
+                             LXMLTreeBuilder)
+
+        if LXML_PRESENT:
+            self.assertEqual(registry.lookup('permissive', 'xml'),
+                             LXMLTreeBuilderForXML)
+        self.assertEqual(registry.lookup('strict', 'html'),
+                          HTMLParserTreeBuilder)
+        if HTML5LIB_PRESENT:
+            self.assertEqual(registry.lookup('html5lib', 'html'),
+                              HTML5TreeBuilder)
+
+    def test_lookup_by_markup_type(self):
+        if LXML_PRESENT:
+            self.assertEqual(registry.lookup('html'), LXMLTreeBuilder)
+            self.assertEqual(registry.lookup('xml'), LXMLTreeBuilderForXML)
+        else:
+            self.assertEqual(registry.lookup('xml'), None)
+            if HTML5LIB_PRESENT:
+                self.assertEqual(registry.lookup('html'), HTML5TreeBuilder)
+            else:
+                self.assertEqual(registry.lookup('html'), HTMLParserTreeBuilder)
+
+    def test_named_library(self):
+        if LXML_PRESENT:
+            self.assertEqual(registry.lookup('lxml', 'xml'),
+                             LXMLTreeBuilderForXML)
+            self.assertEqual(registry.lookup('lxml', 'html'),
+                             LXMLTreeBuilder)
+        if HTML5LIB_PRESENT:
+            self.assertEqual(registry.lookup('html5lib'),
+                              HTML5TreeBuilder)
+
+        self.assertEqual(registry.lookup('html.parser'),
+                          HTMLParserTreeBuilder)
+
+    def test_beautifulsoup_constructor_does_lookup(self):
+        # You can pass in a string.
+        BeautifulSoup("", features="html")
+        # Or a list of strings.
+        BeautifulSoup("", features=["html", "fast"])
+
+        # You'll get an exception if BS can't find an appropriate
+        # builder.
+        self.assertRaises(ValueError, BeautifulSoup,
+                          "", features="no-such-feature")
+
+class RegistryTest(unittest.TestCase):
+    """Test the TreeBuilderRegistry class in general."""
+
+    def setUp(self):
+        self.registry = TreeBuilderRegistry()
+
+    def builder_for_features(self, *feature_list):
+        cls = type('Builder_' + '_'.join(feature_list),
+                   (object,), {'features' : feature_list})
+
+        self.registry.register(cls)
+        return cls
+
+    def test_register_with_no_features(self):
+        builder = self.builder_for_features()
+
+        # Since the builder advertises no features, you can't find it
+        # by looking up features.
+        self.assertEqual(self.registry.lookup('foo'), None)
+
+        # But you can find it by doing a lookup with no features, if
+        # this happens to be the only registered builder.
+        self.assertEqual(self.registry.lookup(), builder)
+
+    def test_register_with_features_makes_lookup_succeed(self):
+        builder = self.builder_for_features('foo', 'bar')
+        self.assertEqual(self.registry.lookup('foo'), builder)
+        self.assertEqual(self.registry.lookup('bar'), builder)
+
+    def test_lookup_fails_when_no_builder_implements_feature(self):
+        builder = self.builder_for_features('foo', 'bar')
+        self.assertEqual(self.registry.lookup('baz'), None)
+
+    def test_lookup_gets_most_recent_registration_when_no_feature_specified(self):
+        builder1 = self.builder_for_features('foo')
+        builder2 = self.builder_for_features('bar')
+        self.assertEqual(self.registry.lookup(), builder2)
+
+    def test_lookup_fails_when_no_tree_builders_registered(self):
+        self.assertEqual(self.registry.lookup(), None)
+
+    def test_lookup_gets_most_recent_builder_supporting_all_features(self):
+        has_one = self.builder_for_features('foo')
+        has_the_other = self.builder_for_features('bar')
+        has_both_early = self.builder_for_features('foo', 'bar', 'baz')
+        has_both_late = self.builder_for_features('foo', 'bar', 'quux')
+        lacks_one = self.builder_for_features('bar')
+        has_the_other = self.builder_for_features('foo')
+
+        # There are two builders featuring 'foo' and 'bar', but
+        # the one that also features 'quux' was registered later.
+        self.assertEqual(self.registry.lookup('foo', 'bar'),
+                          has_both_late)
+
+        # There is only one builder featuring 'foo', 'bar', and 'baz'.
+        self.assertEqual(self.registry.lookup('foo', 'bar', 'baz'),
+                          has_both_early)
+
+    def test_lookup_fails_when_cannot_reconcile_requested_features(self):
+        builder1 = self.builder_for_features('foo', 'bar')
+        builder2 = self.builder_for_features('foo', 'baz')
+        self.assertEqual(self.registry.lookup('bar', 'baz'), None)