[YouTube] Fix n-sig for player e06dea74 (#30582)

From yt-dl commit 48416bc

test/test_youtube_signature.py

@@ -82,6 +82,14 @@ _NSIG_TESTS = [
         'https://www.youtube.com/s/player/f1ca6900/player_ias.vflset/en_US/base.js',
         'cu3wyu6LQn2hse', 'jvxetvmlI9AN9Q',
     ),
+    (
+        'https://www.youtube.com/s/player/8040e515/player_ias.vflset/en_US/base.js',
+        'wvOFaY-yjgDuIEg5', 'HkfBFDHmgw4rsw',
+    ),
+    (
+        'https://www.youtube.com/s/player/e06dea74/player_ias.vflset/en_US/base.js',
+        'AiuodmaDDYw8d3y4bf', 'ankd8eza2T6Qmw',
+    ),
 ]
 
 
@@ -110,10 +118,17 @@ class TestPlayerInfo(unittest.TestCase):
 class TestSignature(unittest.TestCase):
     def setUp(self):
         TEST_DIR = os.path.dirname(os.path.abspath(__file__))
-        self.TESTDATA_DIR = os.path.join(TEST_DIR, 'testdata')
+        self.TESTDATA_DIR = os.path.join(TEST_DIR, 'testdata/sigs')
         if not os.path.exists(self.TESTDATA_DIR):
             os.mkdir(self.TESTDATA_DIR)
 
+    def tearDown(self):
+        try:
+            for f in os.listdir(self.TESTDATA_DIR):
+                os.remove(f)
+        except OSError:
+            pass
+
 
 def t_factory(name, sig_func, url_pattern):
     def make_tfunc(url, sig_input, expected_sig):
@@ -145,12 +160,7 @@ def signature(jscode, sig_input):
 
 
 def n_sig(jscode, sig_input):
-    # Pending implementation of _extract_n_function_name() or similar in
-    # youtube.py, hard-code here
-    # funcname = YoutubeIE(FakeYDL())._extract_n_function_name(jscode)
-    import re
-    funcname = re.search(r'[=(,&|](\w+)\(\w+\),\w+\.set\("n",', jscode)
-    funcname = funcname and funcname.group(1)
+    funcname = YoutubeIE(FakeYDL())._extract_n_function_name(jscode)
     return JSInterpreter(jscode).call_function(funcname, sig_input)