Add test and allow the java options to be picked for a default test group created.

main/Defaults.scala

@@ -318,9 +318,7 @@ object Defaults extends BuildCommon
 		},
 		testOptions <<= (testOptions in TaskGlobal, testListeners) map { (options, ls) => Tests.Listeners(ls) +: options },
 		testExecution <<= testExecutionTask(key),
-		testGrouping <<= testGrouping in TaskGlobal or ((definedTests, fork) map {
-			(tests, fork) => Seq(new Tests.Group("<default>", tests, if (fork) Tests.SubProcess(Seq()) else Tests.InProcess))
-		})
+		testGrouping <<= testGrouping or singleTestGroup(key)
 	) )
 	def testLogger(manager: Streams, baseKey: Scoped)(tdef: TestDefinition): Logger =
 	{
@@ -335,6 +333,10 @@ object Defaults extends BuildCommon
 		val mod = tdef.fingerprint match { case f: SubclassFingerprint => f.isModule; case f: AnnotatedFingerprint => f.isModule; case _ => false }
 		extra.put(name.key, tdef.name).put(isModule, mod)
 	}
+	def singleTestGroup(key: Scoped): Initialize[Task[Seq[Tests.Group]]] =
+		((definedTests in key, fork in key, javaOptions in key) map {
+			(tests, fork, javaOpts) => Seq(new Tests.Group("<default>", tests, if (fork) Tests.SubProcess(javaOpts) else Tests.InProcess))
+		})
 
 	def testExecutionTask(task: Scoped): Initialize[Task[Tests.Execution]] =
 			(testOptions in task, parallelExecution in task, fork in task, tags in task) map {

main/actions/Tests.scala

@@ -182,10 +182,10 @@ object Tests
 		}
 	}
 
-	sealed trait RunPolicy
-	case object InProcess extends RunPolicy
-	final case class SubProcess(javaOptions: Seq[String]) extends RunPolicy
+	sealed trait TestRunPolicy
+	case object InProcess extends TestRunPolicy
+	final case class SubProcess(javaOptions: Seq[String]) extends TestRunPolicy
 
-	final case class Group(name: String, tests: Seq[TestDefinition], runPolicy: RunPolicy)
+	final case class Group(name: String, tests: Seq[TestDefinition], runPolicy: TestRunPolicy)
 }
 

sbt/src/sbt-test/tests/fork/project/ForkTestsTest.scala

@@ -0,0 +1,36 @@
+import sbt._
+import Keys._
+import Tests._
+import Defaults._
+
+object ForkTestsTest extends Build {
+	val totalFiles = 9
+	val groupSize = 3
+
+	val check = TaskKey[Unit]("check", "Check all files were created and remove them.")
+
+	def groupId(idx: Int) = "group_" + (idx + 1)
+	def groupPrefix(idx: Int) = groupId(idx) + "_file_"
+
+	lazy val root = Project("root", file("."), settings = defaultSettings ++  Seq(
+		testGrouping <<= definedTests in Test map { tests =>
+			assert(tests.size == 1)
+			val groups = Stream const tests(0) take totalFiles grouped groupSize
+			for ((ts, idx) <- groups.toSeq.zipWithIndex)	yield {
+				new Group(groupId(idx), ts, SubProcess(Seq("-Dgroup.prefix=" + groupPrefix(idx), "-Dgroup.size=" + ts.size)))
+			}
+		},
+		check := {
+			for (i <- 0 until totalFiles/groupSize)
+				for (j <- 1 to groupSize) {
+					val f = file(groupPrefix(i) + j)
+					if (!f.exists)
+						error("File " + f.getName + " was not created.")
+					else
+						f.delete()
+				}
+		},
+		concurrentRestrictions := Tags.limit(Tags.ForkedTestGroup, 2) :: Nil,
+		libraryDependencies += "org.scalatest" % "scalatest_2.9.0" % "1.6.1" % "test"
+	))
+}

sbt/src/sbt-test/tests/fork/src/test/scala/Ensemble.scala

@@ -0,0 +1,20 @@
+import org.scalatest.FlatSpec
+import org.scalatest.matchers.MustMatchers
+import java.io.File
+
+class Ensemble extends FlatSpec with MustMatchers {
+	val prefix = System.getProperty("group.prefix")
+	val countTo = System.getProperty("group.size").toInt
+
+	"an ensemble" must "create all files" in {
+		@annotation.tailrec
+		def step(i: Int): Unit = {
+			val f = new File(prefix + i)
+			if (!f.createNewFile)
+				step(if (f.exists) i + 1 else i)
+			else
+				i must be <= (countTo)
+		}
+		step(1)
+	}
+}

sbt/src/sbt-test/tests/fork/test

@@ -0,0 +1,2 @@
+> test
+> check