private boolean stopped;
    private final ThreadLocal<Matcher<? extends Throwable>> expectedFailure
            = new ThreadLocal<Matcher<? extends Throwable>>();
    private final SyncPoint syncPoint = new SyncPoint();

    /**
     * Creates an Executor which the test can control.
     */
    protected ExecutorService getExecutor() {
        if (executor == null) {
            executor = new ExecutorImpl();