add test for project dependency

Author: dwickern

src/sbt-test/docker/test-layer-groups-playframework/app/controllers/HomeController.scala

@@ -1,9 +1,10 @@
 package controllers
 
-import javax.inject._
-import play.api._
+import common.Common
 import play.api.mvc._
 
+import javax.inject._
+
 /**
  * This controller creates an `Action` to handle HTTP requests to the
  * application's home page.
@@ -21,4 +22,6 @@ class HomeController @Inject()(val controllerComponents: ControllerComponents) e
   def index() = Action { implicit request: Request[AnyContent] =>
     Ok(views.html.index())
   }
+
+  def helloWorld = Action(Ok(Common.helloWorld))
 }

src/sbt-test/docker/test-layer-groups-playframework/build.sbt

@@ -1,11 +1,19 @@
 name := "test-layer-groups-playframework"
-organization := "com.example"
 
-version := "1.0-SNAPSHOT"
+ThisBuild / organization := "com.example"
+ThisBuild / version := "1.0-SNAPSHOT"
+ThisBuild / scalaVersion := "2.13.16"
 
-lazy val root = (project in file(".")).enablePlugins(PlayScala)
+lazy val root = (project in file(".")).enablePlugins(PlayScala).dependsOn(common)
 
-scalaVersion := "2.13.16"
+// a local project dependency
+lazy val common = project.settings(
+  name := "test-layer-groups-playframework-common",
+
+  // a transitive dependency of the main project
+  // (use any library as long as it's not already a Play dependency)
+  libraryDependencies += "org.typelevel" %% "cats-core" % "2.13.0"
+)
 
 libraryDependencies += guice
 libraryDependencies += "org.scalatestplus.play" %% "scalatestplus-play" % "7.0.1" % Test
@@ -32,6 +40,7 @@ TaskKey[Unit]("checkDockerLayers") := {
     layer20.forall(_.file.getPath.startsWith(csrCacheDirectory.value.getPath)),
     "layer 20 should only contain external libraries"
   )
+  assert(layer20.exists(_.file.name.contains("cats-core")), "layer 20 should contain the common project's dependencies")
 
   val layer30 = layers(Some(30))
   assert(layer30.exists(_.path == "/opt/docker/conf/application.ini"), "layer 30 should contain application.ini")
@@ -44,6 +53,10 @@ TaskKey[Unit]("checkDockerLayers") := {
   )
   assert(layer40.exists(_.file == PlayKeys.playPackageAssets.value), "layer 40 should contain Play's -assets.jar")
   assert(layer40.exists(_.file == packageJavaLauncherJar.value), "layer 40 should contain launcher jar")
+  assert(
+    layer40.exists(_.file == (common / Compile / packageBin).value),
+    "layer 40 should contain the common project jar"
+  )
   assert(
     layer40.exists(layer => makeBashScripts.value.map(_._1).contains(layer.file)),
     "layer 40 should contain start scripts"

src/sbt-test/docker/test-layer-groups-playframework/common/src/main/scala/common/Common.scala

@@ -0,0 +1,7 @@
+package common
+
+import cats.syntax.show._
+
+object Common {
+  def helloWorld: String = show"Hello, world!"
+}

src/sbt-test/docker/test-layer-groups-playframework/conf/routes

@@ -5,6 +5,7 @@
 
 # An example controller showing a sample home page
 GET     /                           controllers.HomeController.index()
+GET     /hello-world                controllers.HomeController.helloWorld
 
 # Map static resources from the /public folder to the /assets URL path
 GET     /assets/*file               controllers.Assets.versioned(path="/public", file: Asset)