[error.html]
  [controller.error() should error the stream]
    expected: FAIL

  [controller.error() on erroring stream should not throw]
    expected: FAIL

  [surplus calls to controller.error() should be a no-op]
    expected: FAIL

  [controller.error() on errored stream should not throw]
    expected: FAIL

  [controller.error() on closed stream should not throw]
    expected: FAIL