How to test import implicit dependencies

[Shamsh Tabrij]

//DataBaseAdapterObject.scala
package services.db
object DataBaseAdapterObject{
  def findAllBlogItems() : List[String] = {
    ........
    ........
    List("One", "Two", "Three")
  }
}

//BaseService.scala
package services
import services.db._
object BaseService {
  implicit val db = DataBaseAdapterObject;
}


//BlogItemService.scala
package services
import services.BaseService._

object BlogItemService {
  def findAll() : List[String] = {
    db.findAllBlogItems()
  }
}


For above implementation I want to write unit test for the BlogItemService.findAll, The problem is because the db val is resolved by import I cannot mock the db object.
Does anybody know how to mock that implicit import db.

The code can be written differently by implementing DI but I want to know if any work around for this case?

[etorreborre]

Can you change any of the code in BlogItemService.scala?

One option would be to rewrite the findAll function so that it delegates to findAllWithDb

  def findAll(): List[String] = 

    findAllWithDb(db)

  def findAllWithDb: DabaseAdapterObject => List[String] = 

     // your implementation

  

Then you can unit test findAllWithDb.

This also moves you toward using a Reader pattern where you can sequence methods like findAllWithDb with a for comprehension as you evolve your application.

Eric.

[Shamsh Tabrij]

Thanks for the reply, Definitely this can be solution but needs more code. I was wondering if there is any way to override the context of db when writing the specification?

[etorreborre]

Sorry I don't know any way that would be absolutely non-invasive with the code you have.

But I can only encourage you to either use a Reader pattern or to use a DI framework and refactor your code. This has really made my life a lot easier for testing specs2 3.x compared to 2.x.

Eric.

[Shamsh Tabrij]

Thanks Eric, I also think the code should be refactored.