BackgroundJobRunner getBackgroundJobRunner(Job job) {
        assertJobExists(job.getJobDetails());
        return backgroundJobRunners.stream()
                .filter(jobRunner -> jobRunner.supports(job))
                .findFirst()
                .orElseThrow(() -> problematicConfigurationException("Could not find a BackgroundJobRunner: either no JobActivator is registered, your Background Job Class is not registered within the IoC container or your Job does not have a default no-arg constructor."));
    }
@Test
    void getBackgroundJobRunnerForJobThatCannotBeRun() {
        final Job job = anEnqueuedJob()
                .<TestServiceThatCannotBeRun>withJobDetails(ts -> ts.doWork())
                .build();
        assertThatThrownBy(() -> backgroundJobServer.getBackgroundJobRunner(job))
                .isInstanceOf(JobRunrException.class);
    }