val mockApp = new GuiceApplicationBuilder()
val db = mockApp.injector.instanceOf[DBApi].database("default")

...

override def afterAll = {
  db.getConnection().close()
  db.shutdown()
}

slick.dbs.default.driver="slick.driver.PostgresDriver$"
slick.dbs.default.db.driver="org.postgresql.Driver"
slick.dbs.default.db.url="jdbc:postgresql://db:5432/hygge_db"
slick.dbs.default.db.user="*****"
slick.dbs.default.db.password="*****"