How to run ScalaTest with Guice DI and Slick? - scala

Question

I don't know how to configure GuiceApplicationBuilder in such a way, that I am able to load controllers that require a DatabaseConfigProvider to be injected.
I'd like to specify an alternative postgres database for testing, or an in memory database (if that is possible).
Code
class User
extends MySpecs
with OneAppPerTest
{
override def newAppForTest( testData: TestData ) = new GuiceApplicationBuilder()
// Somehow bind a database here, I guess?
.build()
"A test" should "test" in
{
val result = Application.instanceCache[api.controller.User]
.apply( app )
.list()( FakeRequest() )
...
}
}
Stacktrace
[info] - should return an entity *** FAILED ***
[info] com.google.inject.ConfigurationException: Guice configuration errors:
[info]
[info] 1) No implementation for play.api.db.slick.DatabaseConfigProvider was bound.
[info] while locating play.api.db.slick.DatabaseConfigProvider
[info] for parameter 1 at api.controller.User.<init>(User.scala:22)
[info] while locating api.controller.User
[info]
[info] 1 error
[info] at com.google.inject.internal.InjectorImpl.getProvider(InjectorImpl.java:1042)
[info] at com.google.inject.internal.InjectorImpl.getProvider(InjectorImpl.java:1001)
[info] at com.google.inject.internal.InjectorImpl.getInstance(InjectorImpl.java:1051)
[info] at play.api.inject.guice.GuiceInjector.instanceOf(GuiceInjectorBuilder.scala:321)
[info] at play.api.inject.guice.GuiceInjector.instanceOf(GuiceInjectorBuilder.scala:316)
[info] at play.api.Application$$anonfun$instanceCache$1.apply(Application.scala:234)
[info] at play.api.Application$$anonfun$instanceCache$1.apply(Application.scala:234)
[info] at play.utils.InlineCache.fresh(InlineCache.scala:69)
[info] at play.utils.InlineCache.apply(InlineCache.scala:55)
[info] ...

Answer 1

You need to add a configuration to your GuiceApplicationBuilder(), then everything should be handled automatically by play framework. Something like this should help:
val app = new GuiceApplicationBuilder()
.configure(
Configuration.from(
Map(
"slick.dbs.YOURDBNAME.driver" -> "slick.driver.H2Driver$",
"slick.dbs.YOURDBNAME.db.driver" -> "org.h2.Driver",
"slick.dbs.YOURDBNAME.db.url" -> "jdbc:h2:mem:",
"slick.dbs.default.driver" -> "slick.driver.MySQLDriver$",
"slick.dbs.default.db.driver" -> "com.mysql.jdbc.Driver"
)
)
)
.in(Mode.Test)
.build()

Answer 2

There is a little bit of setting up in this approach but the final result is fair. First of all start with implementing your own GuiceApplicationLoader by extending it. See my answer how to implement it. Why your own application loader? You can specify different configs/modules per Prod/Dev/Test modes - as well as different data sources. Your main application.conf wouldn't have data source configured. Instead, you would move it to environment specific configurations which would be merged with main configuration by application loader anyway. Your dev.conf would look as follows:
slick.dbs {
default {
driver = "slick.driver.PostgresDriver$",
db {
driver = "org.postgresql.Driver",
url = "jdbc:postgresql://localhost:5432/dev",
user = "postgres"
password = "postgres"
}
}
}
And the trick now is to use same data source name, in this case default, for all other configurations (the database url, drivers, credentials etc. would be different). With such setup, your evolutions will be applied to your test and dev database. Your test.conf could look as follows:
slick.dbs {
default {
// in memory configuration
}
}
In your tests, use WithApplicationLoader with your custom application loader instead and thats it.
#RunWith(classOf[JUnitRunner])
class ApplicationSpec extends Specification {
"Application" should {
"return text/html ok for home" in new WithApplicationLoader(new CustomApplicationLoader) {
val home = route(FakeRequest(routes.ApplicationController.home())).get
status(home) must equalTo(OK)
contentType(home) must beSome.which(_ == "text/html")
}
}
}
Within the test itself, you have an access to app: Application value:
val service = app.injector.instanceOf(classOf[IService])