Scala Play: How to inject test Database into Controller for testing

Question

A new scala-play project (v2.5.6) starts with tests examples like this one:

"HomeController" should {
  "render the index page" in {
    val home = route(app, FakeRequest(GET, "/")).get
    status(home) mustBe OK
  }
}

and controller examples like this one, injecting a Database with Guice:

class DataManagementController @Inject()(db: Database) extends Controller {...}

I would like to test this new controller as above, but injecting a test in-memory database instead of the "default". After hours trying I can't manage to have that. I found clues in

• Testing a Model,
• Override (Guice) bindings

(and external posts using a FakeApplication, although they are very complicated and I'd prefer to follow the official, current version's docs.)

From that I understood that there is an implicit app argument used in route(app, ...), so I tried to override it:

Attempt 1: (compiles but still uses database "default")

class MySpec extends PlaySpec with OneAppPerSuite {

  implicit override lazy val app = new GuiceApplicationBuilder()
    .configure(inMemoryDatabase("test").build()

  "DataManagementController" should { ... }

Attempt 2: (does not compile: "Cannot resolve symbol 'TestDb'")

class MySpec extends PlaySpec with OneAppPerSuite {

  val TestDb = Databases.inMemory(name="test")

  implicit override lazy val app = new GuiceApplicationBuilder()
    .overrides(bind[Database].to[TestDb]).build()

  "DataManagementController" should { ... }

Am I on the right track?

Answer 1

Shouldn't be an issue, but you can try:

implicit override lazy val app = new GuiceApplicationBuilder()
    .overrides(bind(classOf[Database]).to(classOf[TestDb]).build()

instead of

implicit override lazy val app = new GuiceApplicationBuilder()
    .overrides(bind[Database].to[TestDb]).build()

and/or

"" should {
  "" in new App(appBuilder) {
   }
}

where appappBuilder is GuiceApplicationBuilder