Spotify is widely testing its own version of Instagram Stories for musicians and songwriters. "Storyline" provides curated commentary about each song running slideshow-style as the song plays Spotify Tests ‘Storyline’ – a Snapchat-Style Stories Feature Offering Additional Artist Content https://t.co/z7gwyGF1eW by @waxeditorial pic.twitter.com/f4fNHyltJp — MacRumors.com (@MacRumors) May 14, 2019 Currently…