This is a testharness.js-based test.
[FAIL] Property background-attachment value 'scroll, fixed, local'
  assert_equals: expected "scroll, fixed, local" but got "scroll"
[FAIL] Property background-attachment value 'scroll' multiple base values
  assert_equals: expected "scroll" but got "scroll, scroll"
[FAIL] Property background-attachment value 'scroll, fixed, local' multiple base values
  assert_equals: expected "scroll, fixed, local" but got "scroll, fixed"
Harness: the test ran to completion.