PetRepositoryTestTestMethod.kt

@Test
@ExperimentalCoroutinesApi
fun `verify method returns result, caches images, and updates offset`() = runBlocking {
    // Arrange
    val deferred = CompletableDeferred(MockJsonResponse().with(1))

    every {
        mockPetManager.getPetListAsync("78701", null)
    } returns deferred

    // Exercise
    val result = petRepository.getNextPet()

    // Assert
    result.observeForever {
        Assert.assertNotNull(it)
    }
    coVerify {
        mockImageCache.cacheImages(any())
    }
    Assert.assertEquals(deferred.getCompleted().petFinder.lastOffset.value, petRepository.offset)
}