This is a testharness.js-based test.
[FAIL] observer.rootMargin using 'cm'
  Failed to construct 'IntersectionObserver': rootMargin must be specified in pixels or percent.
[FAIL] observer.scrollMargin using 'cm'
  Failed to construct 'IntersectionObserver': scrollMargin must be specified in pixels or percent.
[FAIL] observer.rootMargin using 'mm'
  Failed to construct 'IntersectionObserver': rootMargin must be specified in pixels or percent.
[FAIL] observer.scrollMargin using 'mm'
  Failed to construct 'IntersectionObserver': scrollMargin must be specified in pixels or percent.
[FAIL] observer.rootMargin using 'q'
  Failed to construct 'IntersectionObserver': rootMargin must be specified in pixels or percent.
[FAIL] observer.scrollMargin using 'q'
  Failed to construct 'IntersectionObserver': scrollMargin must be specified in pixels or percent.
[FAIL] observer.rootMargin using 'in'
  Failed to construct 'IntersectionObserver': rootMargin must be specified in pixels or percent.
[FAIL] observer.scrollMargin using 'in'
  Failed to construct 'IntersectionObserver': scrollMargin must be specified in pixels or percent.
[FAIL] observer.rootMargin using 'pt'
  Failed to construct 'IntersectionObserver': rootMargin must be specified in pixels or percent.
[FAIL] observer.scrollMargin using 'pt'
  Failed to construct 'IntersectionObserver': scrollMargin must be specified in pixels or percent.
[FAIL] observer.rootMargin using 'pc'
  Failed to construct 'IntersectionObserver': rootMargin must be specified in pixels or percent.
[FAIL] observer.scrollMargin using 'pc'
  Failed to construct 'IntersectionObserver': scrollMargin must be specified in pixels or percent.
Harness: the test ran to completion.