Defer checking test names until they are needed (after test-compile). Not as immediate feedback, but it is more accurate.

sbt/src/main/scala/sbt/DefaultProject.scala

@@ -299,7 +299,7 @@ abstract class BasicScalaProject extends ScalaProject with BasicDependencyProjec
 	protected def packageProjectAction = zipTask(packageProjectPaths, packageProjectZip) describedAs ProjectPackageDescription
 
 	protected def docAllAction = (doc && docTest) describedAs DocAllDescription
-	protected def packageAllAction = task { None } dependsOn(`package`, packageTest, packageSrc, packageTestSrc, packageDocs) describedAs PackageAllDescription
+	protected def packageAllAction = Empty dependsOn(`package`, packageTest, packageSrc, packageTestSrc, packageDocs) describedAs PackageAllDescription
 	protected def graphSourcesAction = graphSourcesTask(graphSourcesPath, mainSourceRoots, mainCompileConditional.analysis).dependsOn(compile)
 	protected def graphPackagesAction = graphPackagesTask(graphPackagesPath, mainSourceRoots, mainCompileConditional.analysis).dependsOn(compile)
 	protected def incrementVersionAction = task { incrementVersionNumber(); None } describedAs IncrementVersionDescription

sbt/src/main/scala/sbt/ScalaProject.scala

@@ -173,8 +173,8 @@ trait ScalaProject extends SimpleScalaProject with FileTasks with MultiTaskProje
 			val beginTasks = begin.map(toTask).toSeq // test setup tasks
 			val workTasks = work.map(w => toTask(w) dependsOn(beginTasks : _*)) // the actual tests
 			val endTasks = end.map(toTask).toSeq // tasks that perform test cleanup and are run regardless of success of tests
-			val endTask = task { None } named("test-cleanup") dependsOn(endTasks : _*)
-			val rootTask = task { None } named("test-complete") dependsOn(workTasks.toSeq : _*) // the task that depends on all test subtasks
+			val endTask = Empty named("test-cleanup") dependsOn(endTasks : _*)
+			val rootTask = Empty named("test-complete") dependsOn(workTasks.toSeq : _*) // the task that depends on all test subtasks
 			SubWork[Project#Task](rootTask, endTask)
 		}
 		new CompoundTask(work)
@@ -392,17 +392,24 @@ trait MultiTaskProject extends Project
 
 			def filterInclude =
 			{
-				val (exactFilters, testFilters) = testNames.toList.map(GlobFilter.apply).partition(_.isInstanceOf[ExactFilter])
-				val includeTests = exactFilters.map(_.asInstanceOf[ExactFilter].matchName)
-				val toCheck = scala.collection.mutable.HashSet(includeTests: _*)
-				toCheck --= allTests
-
-				if(!toCheck.isEmpty && log.atLevel(Level.Warn))
+				lazy val (exactFilters, testFilters) = testNames.toList.map(GlobFilter.apply).partition(_.isInstanceOf[ExactFilter])
+				lazy val includeTests = exactFilters.map(_.asInstanceOf[ExactFilter].matchName)
+				def checkExistence() =
 				{
-					log.warn("Test(s) not found:")
-					toCheck.foreach(test => log.warn("\t" + test))
+					val toCheck = Set() ++ includeTests -- allTests
+
+					if(!toCheck.isEmpty && log.atLevel(Level.Warn))
+					{
+						log.warn("Test(s) not found:")
+						toCheck.foreach(test => log.warn("\t" + test))
+					}
+					toCheck
+				}
+				lazy val includeTestsSet =
+				{
+					checkExistence()
+					Set(includeTests: _*)
 				}
-				val includeTestsSet = Set(includeTests: _*)
 				(test: String) => includeTestsSet.contains(test) || testFilters.exists(_.accept(test))
 			}
 			

sbt/src/main/scala/sbt/TaskManager.scala

@@ -98,6 +98,7 @@ trait TaskManager{
 		val interactiveDependencyIndex = dependencyList.findIndexOf(_.interactive)
 		require(interactiveDependencyIndex < 0, "Dependency (at index " + interactiveDependencyIndex + ") is interactive.  Interactive tasks cannot be dependencies.")
 	}
+	lazy val Empty = task { None}
 }
 object TaskManager
 {