[update-the-source-set.html]
  [<img src="data:,a" srcset="data:,b 1e0x" data-expect="data:,b">]
    expected: FAIL

  [<picture><source srcset="data:,b" type=""><img src="data:,a" data-expect="data:,b"></picture>]
    expected: FAIL

  [<picture><source srcset="data:,b" type=" "><img src="data:,a" data-expect="data:,b"></picture>]
    expected: FAIL

  [<picture><source srcset="data:,b" type=" image/gif"><img src="data:,a" data-expect="data:,b"></picture>]
    expected: FAIL

  [<picture><source srcset="data:,b" type="image/gif "><img src="data:,a" data-expect="data:,b"></picture>]
    expected: FAIL

  [<picture><source srcset="data:,b" type="image/gif;encodings"><img src="data:,a" data-expect="data:,b"></picture>]
    expected: FAIL

  [<picture><source srcset="data:,b" type="image/*"><img src="data:,a" data-expect="data:,a"></picture>]
    expected: FAIL

  [<picture><source srcset="data:,b" type="image/foobarbaz"><img src="data:,a" data-expect="data:,a"></picture>]
    expected: FAIL