Merge pull request #30 from MonsantoCo/remove-dupes

Remove dupes

src/main/scala/com/monsanto/arch/cloudformation/model/Template.scala

@@ -55,7 +55,7 @@ case class Template(
     if(Resources.isEmpty) throw new RuntimeException("You cannot lookup in a None map")
     val candidates = Resources.get.filter{r => r.name == name}
 
-    if(candidates.length == 0) throw new RuntimeException(s"Resource name $name not found in template: ${this.Description}")
+    if(candidates.isEmpty) throw new RuntimeException(s"Resource name $name not found in template: ${this.Description}")
     if(candidates.length > 1) throw new RuntimeException(s"Name $name is not unique")
 
     candidates.head.asInstanceOf[R]
@@ -65,7 +65,7 @@ case class Template(
     if(Resources.isEmpty) throw new RuntimeException("You cannot lookup in a None map")
     val candidates = Routables.get.filter{r => r.resource.name == name}
 
-    if(candidates.length == 0) throw new RuntimeException(s"Resource name $name not found in template: ${this.Description}")
+    if(candidates.isEmpty) throw new RuntimeException(s"Resource name $name not found in template: ${this.Description}")
     if(candidates.length > 1) throw new RuntimeException(s"Name $name is not unique")
 
     candidates.head.asInstanceOf[SecurityGroupRoutable[R]]
@@ -90,7 +90,11 @@ object Template extends DefaultJsonProtocol {
 
   val EMPTY = Template("", None, None, None, None, None, None)
 
-  def collapse[R <: Resource[R]](rs: Seq[R]) = rs.foldLeft(Template.EMPTY)(_ ++ _)
+  def collapse[R <: Resource[R]](rs: Seq[R]) = {
+    val dupes = rs.groupBy(_.name).collect{case(y,xs) if xs.size>1 => y}
+    if (dupes.nonEmpty) throw new IllegalArgumentException(s"Multiple resources with the same name would clobber each other. Found duplicates of $dupes")
+    rs.foldLeft(Template.EMPTY)(_ ++ _)
+  }
 
   // b/c we really dont need to implement READING yet, and its a bit trickier
   implicit def optionWriter[T : JsonWriter]: JsonWriter[Option[T]] = new JsonWriter[Option[T]] {

src/test/scala/com/monsanto/arch/cloudformation/model/Template_UT.scala

@@ -0,0 +1,15 @@
+package com.monsanto.arch.cloudformation.model
+
+import com.monsanto.arch.cloudformation.model.resource.{CidrBlock, AmazonTag, `AWS::EC2::VPC`}
+import org.scalatest.{Matchers, FlatSpec}
+
+class Template_UT extends FlatSpec with Matchers{
+  it should "throw an exception if some resources have the same name" in {
+
+    val thrown = the[IllegalArgumentException] thrownBy Template.collapse(Seq(
+      `AWS::EC2::VPC`("repeat", CidrBlock(10, 10, 10, 10, 16), Seq(AmazonTag("a", "B"))),
+      `AWS::EC2::VPC`("repeat", CidrBlock(10, 10, 10, 12, 16), Seq(AmazonTag("c", "C")))
+    ))
+    thrown.getMessage should include("repeat")
+  }
+}