}

	// The "pre" output should all have been flushed already.
	if want, got := pre, out.String(); want != got {
		t.Errorf("filter should have already flushed %q, but flushed %q", want, got)
	}

	code, err := f.Finish()
	if err != nil {
		t.Fatal(err)
	}

	// Nothing more should have been written to out.
	if want, got := pre, out.String(); want != got {
		t.Errorf("want output %q, got %q", want, got)
	}

    CRAWLING_EXCEPTION,
    /** Indicates no URL is available in the queue. */
    NO_URL_IN_QUEUE,
    /** Indicates the start of a crawler thread. */
    START_THREAD,
    /** Indicates the finish of a crawler thread. */
    FINISHED_THREAD,
    /** Indicates no response processor is available. */
    NO_RESPONSE_PROCESSOR,
    /** Indicates no rule is available for processing. */
    NO_RULE,

if [[ "$TFCI_DOCKER_PULL_ENABLE" == 1 ]]; then
  # Simple retry logic for docker-pull errors. Sleeps if a pull fails.
  # Pulling an already-pulled container image will finish instantly, so
  # repeating the command costs nothing.
  docker pull "$TFCI_DOCKER_IMAGE" || sleep 15
  docker pull "$TFCI_DOCKER_IMAGE" || sleep 30
  docker pull "$TFCI_DOCKER_IMAGE" || sleep 60