Mockito class is mocked but returns nothing - scala

Question

I am kinda new with Scala and as said in the title, i am trying to mock a class.
DateServiceTest.scala
#RunWith(classOf[JUnitRunner])
class DateServiceTest extends FunSuite with MockitoSugar {
val conf = new SparkConf().setAppName("Simple Application").setMaster("local")
val sc = new SparkContext(conf)
implicit val sqlc = new SQLContext(sc)
val m = mock[ConfigManager]
when(m.getParameter("dates.traitement")).thenReturn("10")
test("mocking test") {
val instance = new DateService
val date = instance.loadDates
assert(date === new DateTime())
}
}
DateService.scala
class DateService extends Serializable with Logging {
private val configManager = new ConfigManager
private lazy val datesTraitement = configManager.getParameter("dates.traitement").toInt
def loadDates() {
val date = selectFromDatabase(datesTraitement)
}
}
Unfortunately when I run the test, datesTraitement returns null instead of 10, but m.getparameter("dates.traitement") does return 10.
Maybe i am doing some kind of anti pattern somewhere but I don't know where, please keep in mind that I am new with all of this and I didn't find any proper example specific to my case on internet.
Thanks for any help.

Answer 1

I think the issue is your mock is not injected, as you create ConfigManager inline in the DateService class.
Instead of
class DateService extends Serializable with Logging {
private val configManager = new ConfigManager
}
try
class DateService(private val configManager: ConfigManager) extends Serializable with Logging
and in your test case inject the mocked ConfigManager when you construct DateService
class DateServiceTest extends FunSuite with MockitoSugar {
val m = mock[ConfigManager]
val instance = new DateService(m)
}