This is a testharness.js-based test.
[FAIL] LF at <leading> should result in Network Error (fetch)
  assert_unreached: Should have rejected: undefined Reached unreachable code
[FAIL] LF at <leading> should result in Network Error frame
  assert_equals: expected null but got Document node with 1 child
[FAIL] CR at <leading> should result in Network Error (fetch)
  assert_unreached: Should have rejected: undefined Reached unreachable code
[FAIL] HTAB at <leading> should result in Network Error (fetch)
  assert_unreached: Should have rejected: undefined Reached unreachable code
[FAIL] HTAB at <leading> should result in Network Error frame
  assert_equals: expected null but got Document node with 1 child
[FAIL] SP at <leading> should result in Network Error (fetch)
  assert_unreached: Should have rejected: undefined Reached unreachable code
[FAIL] SP at <leading> should result in Network Error frame
  assert_equals: expected null but got Document node with 1 child
[FAIL] COLON at <leading> should result in Network Error (fetch)
  assert_unreached: Should have rejected: undefined Reached unreachable code
[FAIL] COLON at <leading> should result in Network Error frame
  assert_equals: expected null but got Document node with 1 child
Harness: the test ran to completion.