[test:youtube_signature] Add `es6` test cases

Authored by: bashonly

test/test_youtube_signature.py

@@ -128,6 +128,11 @@ _SIG_TESTS = [
         '2aq0aqSyOoJXtK73m-uME_jv7-pT15gOFC02RFkGMqWpzEICs69VdbwQ0LDp1v7j8xx92efCJlYFYb1sUkkBSPOlPmXgIARw8JQ0qOAOAA',
         'IAOAOq0QJ8wRAAgXmPlOPSBkkUs1bYFYlJCfe29xx8j7v1pDL0QwbdV96sCIEzpWqMGkFR20CFOg51Tp-7vj_E2u-m37KtXJoOySqa0',
     ),
+    (
+        'https://www.youtube.com/s/player/8a8ac953/tv-player-es6.vflset/tv-player-es6.js',
+        '2aq0aqSyOoJXtK73m-uME_jv7-pT15gOFC02RFkGMqWpzEICs69VdbwQ0LDp1v7j8xx92efCJlYFYb1sUkkBSPOlPmXgIARw8JQ0qOAOAA',
+        'IAOAOq0QJ8wRAAgXmPlOPSBkkUs1bYFYlJCfe29xx8j7v1pDL0QwbdV96sCIEzpWqMGkFR20CFOg51Tp-7vj_E2u-m37KtXJoOySqa0',
+    ),
 ]
 
 _NSIG_TESTS = [
@@ -307,6 +312,10 @@ _NSIG_TESTS = [
         'https://www.youtube.com/s/player/8a8ac953/player_ias_tce.vflset/en_US/base.js',
         'MiBYeXx_vRREbiCCmh', 'RtZYMVvmkE0JE',
     ),
+    (
+        'https://www.youtube.com/s/player/8a8ac953/tv-player-es6.vflset/tv-player-es6.js',
+        'MiBYeXx_vRREbiCCmh', 'RtZYMVvmkE0JE',
+    ),
 ]