PASS WebVTT parser tests, signature-lowercase.vtt
PASS WebVTT parser tests, signature-too-short.vtt
PASS WebVTT parser tests, signature-websrt.vtt
PASS WebVTT parser tests, signature-lowercase.vtt
PASS WebVTT parser tests, signature-too-short.vtt
PASS WebVTT parser tests, signature-websrt.vtt