An example of testing the interaction vs testing the state

StateVsInteractionTesting.kt

// Unit under test
fun toggleFavoriteForJob(job: Job) {
  if (job.isFavorite) {
    cache.unfavorite(job)
  } else {
    cache.favorite(job)
  }
}


// A unit test using interaction testing
fun `toggle favorite with already favorited job verify job is unfavorited`() {
  // Test arrangements and setup

  val job = getTestFavoriteJob()
  jobOperations.toggleFavoriteForJob(job)
  verify(cache).unfavorite(job)
}

// A unit test using state testing
fun `toggle favorite with already favorited job verify job is unfavorited`() {
  // Test arrangements and setup

  val job = getTestFavoriteJob()
  jobOperations.toggleFavoriteForJob(job)
  assertThat(cache.getJobWithId(job.id).isFavorite()).isFalse()
}