How to test methods based on Salat with ScalaTest

Question

I'm writing a web-app using Play 2, Salat (for mongoDB bindin). I would like to test some methods, in the Lesson Model (for instance test the fact that I retrieve the right lesson by id). The problem is that I don't want to pollute my current DB with dummy lessons. How can I use a fake DB using Salat and Scala Test ? Here is one of my test file. It creates two lessons, and insert it into the DB, and it runs some tests on it.

LessonSpec extends FlatSpec with ShouldMatchers {
  object FakeApp extends FakeApplication()

  val newLesson1 = Lesson(
    title = "lesson1",
    level = 5,
    explanations = "expl1",
    questions = Seq.empty)
  LessonDAO.insert(newLesson1)

  val newLesson2 = Lesson(
    title = "lesson2",
    level = 5,
    explanations = "expl2",
    questions = Seq.empty)
  LessonDAO.insert(newLesson2)

  "Lesson Model" should "be retrieved by level" in {
    running(FakeApp) {
      assert(Lesson.findByLevel(5).size === 2)
    }
  }
  it should "be of size 0 if no lesson of the level is found" in {
    running(FakeApp) {
      Lesson.findByLevel(4) should be(Nil)
    }
  }

  it should "be retrieved by title" in {
    running(FakeApp) {
      Lesson.findOneByTitle("lesson1") should be(Some(Lesson("lesson1", 5, "expl1", List())))
    }
  }

}

I searched on the web but i can't find a good link or project that use Salat and ScalaTest.

Answer 1

In my applications, I use a parameter in application.conf to specify the Mongo database name. When initializing my FakeApplication, I override that parameter so that my unit tests can use a real Mongo instance but do not see any of my production data.

Glossing over a few details specific to my application, my tests look something like this:

// wipe any existing data
db.collectionNames.foreach { colName =>
  if (colName != "system.indexes") db.getCollection(colName).drop
}

app = FakeApplication(additionalConfiguration = Map("mongo.db.name" -> "unit-test"))