[scaldi-play 0.5.8] i18n in test

[Ulrik Lejon]

Hi

Lets say I have a service which should be able to create different strings depending on selected language. For example an email service:

import play.api.i18n.Messages

class EmailService {

    def createEmail()(implicit messages: Messages): String = {

        s"""Subject: ${messages("email.subject")}. Message: ${messages("email.message")}"""

    }

}

If I want to unit test this class I would do the following:

import org.specs2.mutable.Specification

import play.api.Logger

import play.api.i18n.Messages

import service.EmailService

import org.specs2.mock._

class EmailServiceTest extends Specification with Mockito {

    "EmailService" should {

        "be able to create an email with a mocked Messages" in {

            implicit val messagesMock = mock[Messages]

            messagesMock.apply(===("email.subject"), anyVarArg) returns "Mocked subject"

            messagesMock.apply(===("email.message"), anyVarArg) returns "Mocked message"

            val email = new EmailService().createEmail()

            email mustEqual s"""Subject: Mocked subject. Message: Mocked message"""

        }

    }

}

But what If I want to test it with a running application, like this:

import org.specs2.mutable.Specification

import play.api.Logger

import play.api.i18n.Messages

import scaldi.play.ScaldiApplicationBuilder._

import service.EmailService

class EmailServiceTest extends Specification {

    "EmailService" should {

        "be able to create an email with an application running" in {

            withScaldiApp() {

                val email = new EmailService().createEmail()

                Logger.error(email)

                email mustEqual s"""Subject: Welcome. Message: Welcome to the future"""

            }

        }

    }

}

My messages.en file:

email.subject=Welcome

email.message=Welcome to the future

If I try to run this test I get:

[play-i18n] $ test

[info] Compiling 1 Scala source to /source/tmp/play-i18n/target/scala-2.11/test-classes...

[error] /source/tmp/play-i18n/test/EmailServiceTest.scala:24: could not find implicit value for parameter messages: play.api.i18n.Messages

[error]                 val email = new EmailService().createEmail()

[error]                                                           ^

[error] one error found

[error] (test:compileIncremental) Compilation failed

[error] Total time: 2 s, completed Jun 30, 2015 8:04:03 PM

So, how do I get hold of the "real" Messages/MessagesApi class in this case?

cheers,

Ulrik

[Oleg Ilyenko]

Hi Ulrik,

In your scenario you need to construct `Messages` somehow and ensure that this `Messages` uses `MessagesApi` that comes directly from the application. It's pretty easy to do - you just need to inject `MessagesApi` and use it to construct implicit `Messages` object (don't forget that you also need to specify the language in order to do this):

import scaldi.Injectable._

"be able to create an email with an application running" in {

  withScaldiInj() { implicit Inj =>

    implicit val messages = new Messages(Lang("en"), inject [MessagesApi])

    val email = new EmailService().createEmail()

    email mustEqual s"""Subject: Welcome. Message: Welcome to the future"""

  }

}

I also used `withScaldiInj` here - it is very similar to `withScaldiApp`, but also gives you access to the `Injector`.

BTW, since `EmailService` already defined in application, you can just inject it instead of creating a new one. It can be very helpful, if `EmailService` have dependencies on it's own:

import scaldi.Injectable._

"be able to create an email with an application running" in {

  withScaldiInj() { implicit Inj =>

    val emailService = inject [EmailService]

    implicit val messages = new Messages(Lang("en"), inject [MessagesApi])

    val email = emailService.createEmail()

    email mustEqual s"""Subject: Welcome. Message: Welcome to the future"""

  }

}

Cheers,

Oleg

[Ulrik Lejon]

Awsome, works great!

Cheers,

Ulrik