This is a testharness.js-based test.
[FAIL] Navigating a popup using window.open("data:text/html,...", "", "undefined")
  assert_true: expected true got false
[FAIL] Navigating a popup using window.open("data:text/html,...", "", "opener")
  assert_true: expected true got false
[FAIL] Navigating a popup using window.open("resources/redirect.py?location=data%3Atext%2Fhtml%2C...", "", "undefined")
  assert_true: expected true got false
[FAIL] Navigating a popup using window.open("resources/redirect.py?location=data%3Atext%2Fhtml%2C...", "", "opener")
  assert_true: expected true got false
Harness: the test ran to completion.