This is a testharness.js-based test.
[FAIL] A source with a stereo buffer that was never started outputs one channel
  assert_array_equals: unstarted source with a stereo buffer expected property 0 to be 1 but got 2 (expected array [1, 1, 1, 1, 1, 1, 1, 1, 1, 1] got [2, 2, 2, 2, 2, 2, 2, 2, 2, 2])
[FAIL] A source whose buffer is set to null outputs one channel
  assert_array_equals: unstarted source with a cleared buffer expected property 0 to be 1 but got 2 (expected array [1, 1, 1, 1, 1, 1, 1, 1, 1, 1] got [2, 2, 2, 2, 2, 2, 2, 2, 2, 2])
[FAIL] A playing source whose buffer is null outputs one channel
  assert_array_equals: playing source with a cleared buffer expected property 0 to be 1 but got 2 (expected array [1, 1, 1, 1, 1, 1, 1, 1, 1, 1] got [2, 1, 1, 1, 1, 1, 1, 1, 1, 1])
Harness: the test ran to completion.