[testurl] Add extractor

This is a pseudo extractor that can be used to quickly look up test URLs, or test without the test harness.

youtube_dl/extractor/testurl.py

@@ -0,0 +1,66 @@
+from __future__ import unicode_literals
+
+import re
+
+from .common import InfoExtractor
+from ..utils import ExtractorError
+
+
+class TestURLIE(InfoExtractor):
+    """ Allows adressing of the test cases as test:yout.*be_1 """
+
+    IE_DESC = False  # Do not list
+    _VALID_URL = r'test(?:url)?:(?P<id>(?P<extractor>.+?)(?:_(?P<num>[0-9]+))?)$'
+
+    def _real_extract(self, url):
+        from ..extractor import gen_extractors
+
+        mobj = re.match(self._VALID_URL, url)
+        video_id = mobj.group('id')
+        extractor_id = mobj.group('extractor')
+        all_extractors = gen_extractors()
+
+        rex = re.compile(extractor_id, flags=re.IGNORECASE)
+        matching_extractors = [
+            e for e in all_extractors if rex.search(e.IE_NAME)]
+
+        if len(matching_extractors) == 0:
+            raise ExtractorError(
+                'No extractors matching %r found' % extractor_id,
+                expected=True)
+        elif len(matching_extractors) > 1:
+            # Is it obvious which one to pick?
+            try:
+                extractor = next(
+                    ie for ie in matching_extractors
+                    if ie.IE_NAME.lower() == extractor_id.lower())
+            except StopIteration:
+                raise ExtractorError(
+                    ('Found multiple matching extractors: %s' %
+                        ' '.join(ie.IE_NAME for ie in matching_extractors)),
+                    expected=True)
+
+        num_str = mobj.group('num')
+        num = int(num_str) if num_str else 0
+
+        testcases = []
+        t = getattr(extractor, '_TEST', None)
+        if t:
+            testcases.append(t)
+        testcases.extend(getattr(extractor, '_TESTS', []))
+
+        try:
+            tc = testcases[num]
+        except IndexError:
+            raise ExtractorError(
+                ('Test case %d not found, got only %d tests' %
+                    (num, len(testcases))),
+                expected=True)
+
+        self.to_screen('Test URL: %s' % tc['url'])
+
+        return {
+            '_type': 'url',
+            'url': tc['url'],
+            'id': video_id,
+        }