I wonder if the code that I’ve written reflects proper way of testing WorkManager with use of Hilt.

Details

My worker is initialized in Application class:

@HiltAndroidApp
class ExpenseTrackerApp : Application(), Configuration.Provider {

    @Inject
    lateinit var workerFactory: HiltWorkerFactory

    override val workManagerConfiguration: Configuration
        get() =
            Configuration.Builder()
                .setWorkerFactory(workerFactory)
                .build()

    override fun onCreate() {
        super.onCreate()
        schedulePaymentsWork()
    }


 private fun schedulePaymentsWork() {
        // logic for determining initial delay.. 

        val workRequest =
            PeriodicWorkRequestBuilder<ScheduledPaymentsWorker>(1, TimeUnit.DAYS)
                .setInitialDelay(initialDelay, TimeUnit.MILLISECONDS)
                .build()
        WorkManager.getInstance(this).enqueueUniquePeriodicWork(
            "ScheduledPaymentsWorker",
            ExistingPeriodicWorkPolicy.KEEP,
            workRequest
        )
    }

What I want to test here is delay, so I created following tests:

@HiltAndroidTest
class ScheduledPaymentsWorkerTest {

    @get:Rule
    var hiltRule = HiltAndroidRule(this)

    @Inject
    lateinit var workerFactory: HiltWorkerFactory

    @Before
    fun setUp() {
        hiltRule.inject()

        val context = InstrumentationRegistry.getInstrumentation().targetContext
        val config = Configuration.Builder()
            .setMinimumLoggingLevel(Log.DEBUG)
            .setExecutor(SynchronousExecutor())
            .setWorkerFactory(workerFactory)
            .build()

        WorkManagerTestInitHelper.initializeTestWorkManager(context, config)
    }

    @Test
    @Throws(Exception::class)
    fun testInitialDelay() {

         // same logic for determining delay as in production code .. 

        val request = PeriodicWorkRequestBuilder<ScheduledPaymentsWorker>(1, TimeUnit.DAYS)
            .setInitialDelay(initialDelay, TimeUnit.MILLISECONDS)
            .build()

        val workManager = WorkManager.getInstance(ApplicationProvider.getApplicationContext())
        val testDriver = WorkManagerTestInitHelper.getTestDriver(ApplicationProvider.getApplicationContext())
        workManager.enqueue(request).result.get()
        testDriver!!.setPeriodDelayMet(request.id)
        val workInfo = workManager.getWorkInfoById(request.id).get()

        assertThat(workInfo.state, `is`(WorkInfo.State.ENQUEUED))

    }
}

Questions

Is that a proper way of integration tests of WorkManager?
Where I’ve my doubts is the place where initial delay is set. Should I really write the logic twice? In production and in test code?

Or should I use custom application class? Similar question was posted here