diff --git a/.gitignore b/.gitignore
index 69d86527a270..95d95ca1158a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -28,4 +28,5 @@ classes/
 
 # Partest
 tests/partest-generated/
+tests/locks/
 /test-classes/
diff --git a/project/Build.scala b/project/Build.scala
index 3f8a9b5225ec..504185e65f6c 100644
--- a/project/Build.scala
+++ b/project/Build.scala
@@ -2,6 +2,7 @@ import sbt.Keys._
 import sbt._
 import java.io.{ RandomAccessFile, File }
 import java.nio.channels.FileLock
+import scala.reflect.io.Path
 
 object DottyBuild extends Build {
 
@@ -16,8 +17,6 @@ object DottyBuild extends Build {
     // "-XX:+HeapDumpOnOutOfMemoryError", "-Xmx1g", "-Xss2m"
   )
 
-  var partestLock: FileLock = null
-
   val defaults = Defaults.defaultSettings ++ Seq(
     scalaVersion in Global := "2.11.5",
     version in Global := "0.1-SNAPSHOT",
@@ -42,16 +41,16 @@ object DottyBuild extends Build {
     // to get Scala 2.11
     resolvers += Resolver.sonatypeRepo("releases"),
 
-    // get reflect and xml onboard
-    libraryDependencies ++= Seq("org.scala-lang" % "scala-reflect" % scalaVersion.value,
-                                "org.scala-lang.modules" %% "scala-xml" % "1.0.1",
-                                "me.d-d" % "scala-compiler" % "2.11.5-20150506-175515-8fc7635b56",
+    // get libraries onboard
+    partestDeps := Seq("me.d-d" % "scala-compiler" % "2.11.5-20150506-175515-8fc7635b56",
+                      "org.scala-lang" % "scala-reflect" % scalaVersion.value,
+                      "org.scala-lang" % "scala-library" % scalaVersion.value % "test"),
+    libraryDependencies ++= partestDeps.value,
+    libraryDependencies ++= Seq("org.scala-lang.modules" %% "scala-xml" % "1.0.1",
                                 "org.scala-lang.modules" %% "scala-partest" % "1.0.5" % "test",
+                                "com.novocode" % "junit-interface" % "0.11" % "test",
                                 "jline" % "jline" % "2.12"),
 
-    // get junit onboard
-    libraryDependencies += "com.novocode" % "junit-interface" % "0.11" % "test",
-
     // scalac options
     scalacOptions in Global ++= Seq("-feature", "-deprecation", "-language:_"),
 
@@ -62,14 +61,26 @@ object DottyBuild extends Build {
 
     // enable verbose exception messages for JUnit
     testOptions in Test += Tests.Argument(TestFrameworks.JUnit, "-a", "-v", "--run-listener=test.ContextEscapeDetector"),
-    testOptions in Test += Tests.Cleanup({ () => if (partestLock != null) partestLock.release }),
-    // when this file is locked, running test generates the files for partest
-    // otherwise it just executes the tests directly
+    testOptions in Test += Tests.Cleanup({ () => partestLockFile.delete }),
+
     lockPartestFile := {
-      val partestLockFile = "." + File.separator + "tests" + File.separator + "partest.lock"
-      partestLock = new RandomAccessFile(partestLockFile, "rw").getChannel.tryLock
+      // When this file is present, running `test` generates the files for
+      // partest. Otherwise it just executes the tests directly.
+      val lockDir = partestLockFile.getParentFile
+      lockDir.mkdirs
+      // Cannot have concurrent partests as they write to the same directory.
+      if (lockDir.list.size > 0)
+        throw new RuntimeException("ERROR: sbt partest: another partest is already running, pid in lock file: " + lockDir.list.toList.mkString(" "))
+      partestLockFile.createNewFile
+      partestLockFile.deleteOnExit
+    },
+    runPartestRunner <<= Def.taskDyn {
+      val jars = Seq((packageBin in Compile).value.getAbsolutePath) ++ 
+          getJarPaths(partestDeps.value, ivyPaths.value.ivyHome)
+      val dottyJars  = "-dottyJars " + jars.length + " " + jars.mkString(" ")
+      // Provide the jars required on the classpath of run tests
+      runTask(Test, "dotty.partest.DPConsoleRunner", dottyJars)
     },
-    runPartestRunner <<= runTask(Test, "dotty.partest.DPConsoleRunner", "") dependsOn (test in Test),
 
     // Adjust classpath for running dotty
     mainClass in (Compile, run) := Some("dotty.tools.dotc.Main"),
@@ -79,31 +90,31 @@ object DottyBuild extends Build {
 
     // http://grokbase.com/t/gg/simple-build-tool/135ke5y90p/sbt-setting-jvm-boot-paramaters-for-scala
     javaOptions <++= (managedClasspath in Runtime, packageBin in Compile) map { (attList, bin) =>
-       // put the Scala {library, reflect} in the classpath
-       val path = for {
-         file <- attList.map(_.data)
-         path = file.getAbsolutePath
-       } yield "-Xbootclasspath/p:" + path
-       // dotty itself needs to be in the bootclasspath
-       val fullpath = ("-Xbootclasspath/a:" + bin) :: path.toList
-       // System.err.println("BOOTPATH: " + fullpath)
-
-       val travis_build = // propagate if this is a travis build
-         if (sys.props.isDefinedAt(TRAVIS_BUILD))
-           List(s"-D$TRAVIS_BUILD=${sys.props(TRAVIS_BUILD)}") ::: travisMemLimit
-         else
-           List()
-
-       val tuning =
-         if (sys.props.isDefinedAt("Oshort"))
-           // Optimize for short-running applications, see https://github.com/lampepfl/dotty/issues/222
-           List("-XX:+TieredCompilation", "-XX:TieredStopAtLevel=1")
+      // put the Scala {library, reflect} in the classpath
+      val path = for {
+        file <- attList.map(_.data)
+        path = file.getAbsolutePath
+      } yield "-Xbootclasspath/p:" + path
+      // dotty itself needs to be in the bootclasspath
+      val fullpath = ("-Xbootclasspath/a:" + bin) :: path.toList
+      // System.err.println("BOOTPATH: " + fullpath)
+
+      val travis_build = // propagate if this is a travis build
+        if (sys.props.isDefinedAt(TRAVIS_BUILD))
+          List(s"-D$TRAVIS_BUILD=${sys.props(TRAVIS_BUILD)}") ::: travisMemLimit
         else
           List()
 
-      tuning ::: agentOptions ::: travis_build ::: fullpath
+      val tuning =
+        if (sys.props.isDefinedAt("Oshort"))
+          // Optimize for short-running applications, see https://github.com/lampepfl/dotty/issues/222
+          List("-XX:+TieredCompilation", "-XX:TieredStopAtLevel=1")
+        else
+          List()
+
+      ("-DpartestParentID=" + pid) :: tuning ::: agentOptions ::: travis_build ::: fullpath
     }
-  ) ++ addCommandAlias("partest", ";lockPartestFile;runPartestRunner")
+  ) ++ addCommandAlias("partest", ";test:compile;lockPartestFile;test:test;runPartestRunner")
 
   lazy val dotty = Project(id = "dotty", base = file("."), settings = defaults)
 
@@ -154,7 +165,23 @@ object DottyBuild extends Build {
   lazy val benchmarks = Project(id = "dotty-bench", settings = benchmarkSettings,
     base = file("bench")) dependsOn(dotty % "compile->test")
 
-  lazy val lockPartestFile = TaskKey[Unit]("lockPartestFile", "Creates the file lock on  ./tests/partest.lock")
-  lazy val runPartestRunner = TaskKey[Unit]("runPartestRunner", "Runs partests")
-
+  // Partest tasks
+  lazy val lockPartestFile = TaskKey[Unit]("lockPartestFile", "Creates the lock file at ./tests/locks/partest-<pid>.lock")
+  lazy val partestLockFile = new File("." + File.separator + "tests" + File.separator + "locks" + File.separator + s"partest-$pid.lock")
+  def pid = java.lang.Long.parseLong(java.lang.management.ManagementFactory.getRuntimeMXBean().getName().split("@")(0))
+
+  lazy val runPartestRunner = TaskKey[Unit]("runPartestRunner", "Runs partest")
+
+  lazy val partestDeps = SettingKey[Seq[ModuleID]]("partestDeps", "Finds jars for partest dependencies")
+  def getJarPaths(modules: Seq[ModuleID], ivyHome: Option[File]): Seq[String] = ivyHome match {
+    case Some(home) => 
+      modules.map({ module => 
+        val file = Path(home) / Path("cache") / 
+          Path(module.organization) / Path(module.name) / Path("jars") /
+          Path(module.name + "-" + module.revision + ".jar")
+        if (!file.isFile) throw new RuntimeException("ERROR: sbt getJarPaths: dependency jar not found: " + file)
+        else file.jfile.getAbsolutePath
+      })
+    case None => throw new RuntimeException("ERROR: sbt getJarPaths: ivyHome not defined")
+  }
 }
diff --git a/test/dotc/tests.scala b/test/dotc/tests.scala
index 61ebae609c44..88d076fd3b61 100644
--- a/test/dotc/tests.scala
+++ b/test/dotc/tests.scala
@@ -35,6 +35,7 @@ class tests extends CompilerTest {
   val posDir        = testsDir + "pos/"
   val posSpecialDir = testsDir + "pos-special/"
   val negDir        = testsDir + "neg/"
+  val runDir        = testsDir + "run/"
   val newDir        = testsDir + "new/"
 
   val sourceDir = "./src/"
@@ -44,7 +45,8 @@ class tests extends CompilerTest {
   val coreDir   = dotcDir + "core/"
 
   @Test def pickle_pickleOK = compileDir(testsDir, "pickling", testPickling)
-  @Test def pickle_pickling = compileDir(coreDir, "pickling", testPickling)
+// This directory doesn't exist anymore
+// @Test def pickle_pickling = compileDir(coreDir, "pickling", testPickling)
   @Test def pickle_ast = compileDir(dotcDir, "ast", testPickling)
 
   //@Test def pickle_core = compileDir(dotcDir, "core", testPickling, xerrors = 2) // two spurious comparison errors in Types and TypeOps
@@ -136,14 +138,19 @@ class tests extends CompilerTest {
   @Test def neg_instantiateAbstract = compileFile(negDir, "instantiateAbstract", xerrors = 8)
   @Test def neg_selfInheritance = compileFile(negDir, "selfInheritance", xerrors = 5)
 
-  @Test def dotty = compileDir(toolsDir, "", "-deep" :: allowDeepSubtypes ++ twice) // note the -deep argument
+  @Test def run_hello = runFile(runDir, "hello")
+  @Test def run_lazyVals = runFile(runDir, "lazyVals")
+
+
+  @Test def dotty = compileDir(dottyDir, "tools", "-deep" :: allowDeepSubtypes ++ twice) // note the -deep argument
+
 
   @Test def dotc_ast = compileDir(dotcDir, "ast")
   @Test def dotc_config = compileDir(dotcDir, "config")
   @Test def dotc_core = compileDir(dotcDir, "core")("-Yno-double-bindings" :: allowDeepSubtypes)// twice omitted to make tests run faster
 
-
-  @Test def dotc_core_pickling = compileDir(coreDir, "pickling")(allowDeepSubtypes)// twice omitted to make tests run faster
+// This directory doesn't exist anymore
+//  @Test def dotc_core_pickling = compileDir(coreDir, "pickling")(allowDeepSubtypes)// twice omitted to make tests run faster
 
   @Test def dotc_transform = compileDir(dotcDir, "transform")// twice omitted to make tests run faster
 
diff --git a/test/dotty/partest/DPConsoleRunner.scala b/test/dotty/partest/DPConsoleRunner.scala
index d21b5e98353a..31b8467d347c 100644
--- a/test/dotty/partest/DPConsoleRunner.scala
+++ b/test/dotty/partest/DPConsoleRunner.scala
@@ -4,26 +4,43 @@
 
 package dotty.partest
 
+import scala.reflect.io.AbstractFile
 import scala.tools.partest._
 import scala.tools.partest.nest._
+import scala.util.matching.Regex
+import tools.nsc.io.{ File => NSCFile }
 import java.io.File
 import java.net.URLClassLoader
 
 /** Runs dotty partest from the Console, discovering test sources in
   * DPConfig.testRoot that have been generated automatically by
-  * DPPrepJUnitRunner. Use `sbt test` to run.
+  * DPPrepJUnitRunner. Use `sbt partest` to run. If additional jars are
+  * required by some run tests, add them to partestDeps in the sbt Build.scala.
   */
 object DPConsoleRunner {
   def main(args: Array[String]): Unit = {
-    new DPConsoleRunner(args mkString (" ")).runPartest
+    // unfortunately sbt runTask passes args as single string
+    // extra jars for run tests are passed with -dottyJars <count> <jar1> <jar2> ...
+    val jarFinder = """-dottyJars (\d*) (.*)""".r
+    val (jarList, otherArgs) = args.toList.partition(jarFinder.findFirstIn(_).isDefined)
+    val extraJars = jarList match {
+      case Nil => sys.error("Error: DPConsoleRunner needs \"-dottyJars <jarCount> <jars>*\".")
+      case jarFinder(nr, jarString) :: Nil => 
+        val jars = jarString.split(" ").toList
+        if (jars.length.toString != nr)
+          sys.error("Error: DPConsoleRunner found wrong number of dottyJars: " + jars + ", expected: " + nr + ". Make sure the path doesn't contain any spaces.")
+        else jars
+      case list => sys.error("Error: DPConsoleRunner found several -dottyJars options: " + list)
+    }
+    new DPConsoleRunner(otherArgs mkString (" "), extraJars).runPartest
   }
 }
 
 // console runner has a suite runner which creates a test runner for each test
-class DPConsoleRunner(args: String) extends ConsoleRunner(args) {
+class DPConsoleRunner(args: String, extraJars: List[String]) extends ConsoleRunner(args) {
   override val suiteRunner = new DPSuiteRunner (
     testSourcePath = optSourcePath getOrElse DPConfig.testRoot,
-    fileManager = null, // new FileManager(ClassPath split PathResolver.Environment.javaUserClassPath map (Path(_))), // the script sets up our classpath for us via ant
+    fileManager = new DottyFileManager(extraJars),
     updateCheck = optUpdateCheck,
     failed = optFailed)
 
@@ -31,8 +48,15 @@ class DPConsoleRunner(args: String) extends ConsoleRunner(args) {
   def runPartest = super.run
 }
 
+class DottyFileManager(extraJars: List[String]) extends FileManager(Nil) {
+  lazy val extraJarList = extraJars.map(NSCFile(_))
+  override lazy val libraryUnderTest  = Path(extraJars.find(_.contains("scala-library")).getOrElse(""))
+  override lazy val reflectUnderTest  = Path(extraJars.find(_.contains("scala-reflect")).getOrElse(""))
+  override lazy val compilerUnderTest = Path(extraJars.find(_.contains("dotty")).getOrElse(""))
+}
+
 class DPSuiteRunner(testSourcePath: String, // relative path, like "files", or "pending"
-  fileManager: FileManager,
+  fileManager: DottyFileManager,
   updateCheck: Boolean,
   failed: Boolean,
   javaCmdPath: String = PartestDefaults.javaCmd,
@@ -83,7 +107,7 @@ extends SuiteRunner(testSourcePath, fileManager, updateCheck, failed, javaCmdPat
   // but it doesn't seem to be used anywhere
 }
 
-class DPTestRunner(testFile: File, suiteRunner: SuiteRunner) extends nest.Runner(testFile, suiteRunner) {
+class DPTestRunner(testFile: File, suiteRunner: DPSuiteRunner) extends nest.Runner(testFile, suiteRunner) {
   // override to provide DottyCompiler
   override def newCompiler = new dotty.partest.DPDirectCompiler(this)
 
@@ -117,7 +141,6 @@ class DPTestRunner(testFile: File, suiteRunner: SuiteRunner) extends nest.Runner
     case class CompSucceeded() extends NegTestState
 
     def nerrIsOk(reason: String) = {
-      import scala.util.matching.Regex
       val nerrFinder = """compilation failed with (\d+) errors""".r
       reason match {
         case nerrFinder(found) => 
@@ -187,4 +210,8 @@ class DPTestRunner(testFile: File, suiteRunner: SuiteRunner) extends nest.Runner
     def description = s"dotc $fsString"
     lazy val result = { pushTranscript(description) ; attemptCompile(fs) }
   }
+
+  // override to add dotty and scala jars to classpath
+  override def extraClasspath = suiteRunner.fileManager.asInstanceOf[DottyFileManager].extraJarList ::: super.extraClasspath
+
 }
diff --git a/test/partest b/test/partest
new file mode 100755
index 000000000000..5794e2e5793e
--- /dev/null
+++ b/test/partest
@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+# partest error message references partest script to update check files, but
+# doesn't work for dotty because we don't know where tests came from.
+
+if [ $1='--update-check' ];
+then
+  echo """ERROR: Since dotty partest runs on generated files, please update the check
+files in the original location (run tests) or update the expected error count
+(neg tests) in the test file."
+else
+  echo "This script doesn't launch partest, please use sbt partest instead."
+fi
\ No newline at end of file
diff --git a/test/test/CompilerTest.scala b/test/test/CompilerTest.scala
index f404c79ba872..0e5c9a6b47fe 100644
--- a/test/test/CompilerTest.scala
+++ b/test/test/CompilerTest.scala
@@ -5,7 +5,7 @@ import dotty.tools.dotc.{Main, Bench, Driver}
 import dotty.tools.dotc.reporting.Reporter
 import scala.collection.mutable.ListBuffer
 import scala.reflect.io.{ Path, Directory, File => SFile }
-import scala.tools.partest.nest.FileManager
+import scala.tools.partest.nest.{ FileManager, NestUI }
 import java.io.{ RandomAccessFile, File => JFile }
 
 import org.junit.Test
@@ -14,20 +14,24 @@ import org.junit.Test
 /** This class has two modes: it can directly run compiler tests, or it can
   * generate the necessary file structure for partest in the directory
   * DPConfig.testRoot. Both modes are regular JUnit tests. Which mode is used
-  * depends on the existence of the tests/runPartest.flag file which is created
-  * by sbt to trigger partest generation. Sbt can then run partest on the
-  * generated sources.
+  * depends on the existence of the tests/locks/partest-ppid.lock file which is
+  * created by sbt to trigger partest generation. Sbt will then run partest on
+  * the generated sources.
   *
   * Through overriding the partestableXX methods, tests can always be run as
-  * JUnit compiler tests.
+  * JUnit compiler tests. Run tests cannot be run by JUnit, only by partest.
   *
-  * A test can either be a file or a directory. The test is in a parent
-  * directory that determines the kind of test:
+  * A test can either be a file or a directory. Partest will generate a
+  * <test>-<kind>.log file with output of failed tests. Partest reads compiler
+  * flags and the number of errors expected from a neg test from <test>.flags
+  * and <test>.nerr files (also generated). The test is in a parent directory
+  * that determines the kind of test:
   * - pos: checks that compilation succeeds
   * - neg: checks that compilation fails with the given number of errors
-  * (- run: compilation succeeds and running generates the given output.)
-  * For partest, compiler flags and the number of errors expected from a neg
-  * test are read from test.flags and test.nerr files (also generated).
+  * - run: compilation succeeds, partest: test run generates the output in
+  *        <test>.check. Run tests always need to be:
+  *        object Test { def main(args: Array[String]): Unit = ... }
+  *        Classpath jars can be added to partestDeps in the sbt Build.scala.
   */
 abstract class CompilerTest extends DottyTest {
 
@@ -41,18 +45,20 @@ abstract class CompilerTest extends DottyTest {
   def partestableList(testName: String, files: List[String], args: List[String], xerrors: Int) = true
 
   val generatePartestFiles = {
-    val partestLockFile = "." + JFile.separator + "tests" + JFile.separator + "partest.lock"
-    try {
-      val partestLock = new RandomAccessFile(partestLockFile, "rw").getChannel.tryLock
-      if (partestLock != null) { // file not locked by sbt -> don't generate partest
-        partestLock.release
-        false
-      } else true
-    } catch {
-      // if sbt doesn't fork in Test, the tryLock request will throw instead of
-      // returning null, because locks are per JVM, not per thread
-      case ex: java.nio.channels.OverlappingFileLockException => true
-    }
+    /* Because we fork in test, the JVM in which this JUnit test runs has a
+     * different pid from the one that started the partest. But the forked VM
+     * receives the pid of the parent as system property. If the lock file
+     * exists, the parent is requesting partest generation. This mechanism
+     * allows one sbt instance to run test (JUnit only) and another partest.
+     * We cannot run two instances of partest at the same time, because they're
+     * writing to the same directories. The sbt lock file generation prevents
+     * this.
+     */
+    val pid = System.getProperty("partestParentID")
+    if (pid == null)
+      false
+    else
+      new JFile("." + JFile.separator + "tests" + JFile.separator + "locks" + JFile.separator + s"partest-$pid.lock").exists
   }
 
   // Delete generated files from previous run
@@ -60,8 +66,11 @@ abstract class CompilerTest extends DottyTest {
     CompilerTest.init
 
   /** Always run with JUnit. */
-  def compileLine(cmdLine: String, xerrors: Int = 0)(implicit defaultOptions: List[String]): Unit =
+  def compileLine(cmdLine: String, xerrors: Int = 0)(implicit defaultOptions: List[String]): Unit = {
+    if (generatePartestFiles)
+      NestUI.echoWarning("WARNING: compileLine will always run with JUnit, no partest files generated.")
     compileArgs(cmdLine.split("\n"), xerrors)
+  }
 
   /** Compiles the given code file.
     *
@@ -73,12 +82,15 @@ abstract class CompilerTest extends DottyTest {
     * @param extension the file extension, .scala by default
     * @param defaultOptions more arguments to the compiler
     */
-  def compileFile(prefix: String, fileName: String, args: List[String] = Nil, xerrors: Int = 0, extension: String = ".scala")
+  def compileFile(prefix: String, fileName: String, args: List[String] = Nil, xerrors: Int = 0, 
+      extension: String = ".scala", runTest: Boolean = false)
       (implicit defaultOptions: List[String]): Unit = {
     if (!generatePartestFiles || !partestableFile(prefix, fileName, extension, args ++ defaultOptions, xerrors)) {
+      if (runTest)
+        NestUI.echoWarning(s"WARNING: run tests can only be run by partest, JUnit just verifies compilation: $prefix$fileName$extension")
       compileArgs((s"$prefix$fileName$extension" :: args).toArray, xerrors)
     } else {
-      val kind = testKind(xerrors)
+      val kind = testKind(prefix, xerrors, runTest)
       println(s"generating partest files for test file: $prefix$fileName$extension of kind $kind")
 
       val sourceFile = new JFile(prefix + fileName + extension)
@@ -90,11 +102,17 @@ abstract class CompilerTest extends DottyTest {
       }
     }
   }
+  def runFile(prefix: String, fileName: String, args: List[String] = Nil, xerrors: Int = 0, 
+      extension: String = ".scala")(implicit defaultOptions: List[String]): Unit =
+    compileFile(prefix, fileName, args, xerrors, extension, true)
 
   /** Compiles the code files in the given directory together. If args starts
     * with "-deep", all files in subdirectories (and so on) are included. */
-  def compileDir(prefix: String, dirName: String, args: List[String] = Nil, xerrors: Int = 0)(implicit defaultOptions: List[String]): Unit = {
+  def compileDir(prefix: String, dirName: String, args: List[String] = Nil, xerrors: Int = 0, runTest: Boolean = false)
+      (implicit defaultOptions: List[String]): Unit = {
     if (!generatePartestFiles || !partestableDir(prefix, dirName, args ++ defaultOptions, xerrors)) {
+      if (runTest)
+        NestUI.echoWarning(s"WARNING: run tests can only be run by partest, JUnit just verifies compilation: $prefix$dirName")
       val dir = Directory(prefix + dirName)
       val (files, normArgs) = args match {
         case "-deep" :: args1 => (dir.deepFiles, args1)
@@ -107,18 +125,24 @@ abstract class CompilerTest extends DottyTest {
         case "-deep" :: args1 => (flattenDir(prefix, dirName), args1 ++ defaultOptions, "deep")
         case _ => (new JFile(prefix + dirName), args ++ defaultOptions, "shallow")
       }
-      val kind = testKind(xerrors)
+      val kind = testKind(prefix, xerrors, runTest)
       println(s"generating partest files for test directory ($deep): $prefix$dirName of kind $kind")
 
       if (sourceDir.exists) {
         val firstDest = Directory(DPConfig.testRoot + JFile.separator + kind + JFile.separator + dirName)
-        computeDestAndCopyFiles(sourceDir, firstDest, kind, args ++ defaultOptions, xerrors.toString)
-        if (deep == "deep") sourceDir.delete
+        computeDestAndCopyFiles(sourceDir, firstDest, kind, flags, xerrors.toString)
+        if (deep == "deep") {
+          sourceDir.listFiles.foreach(_.delete)
+          sourceDir.delete
+        }
       } else {
         throw new java.io.FileNotFoundException(s"Unable to locate test dir $prefix$dirName")
       }
     }
   }
+  def runDir(prefix: String, dirName: String, args: List[String] = Nil, xerrors: Int = 0)
+      (implicit defaultOptions: List[String]): Unit =
+    compileDir(prefix, dirName, args, xerrors, true)
 
   /** Compiles each source in the directory path separately by calling
     * compileFile resp. compileDir. */
@@ -161,10 +185,18 @@ abstract class CompilerTest extends DottyTest {
   }
 
   // In particular, don't copy flags from scalac tests
-  private val extensionsToCopy = scala.collection.immutable.HashSet("scala", "java")
+  private val extensionsToCopy = scala.collection.immutable.HashSet("scala", "java", "check")
 
   /** Determines what kind of test to run. */
-  private def testKind(xerrors: Int) = if (xerrors > 0) "neg" else "pos"
+  private def testKind(prefixDir: String, xerrors: Int, runTest: Boolean) = {
+    if (runTest) "run"
+    else if (xerrors > 0) "neg"
+    else if (prefixDir.endsWith("run" + JFile.separator)) {
+      NestUI.echoWarning("WARNING: test is being run as pos test despite being in a run directory. " + 
+        "Use runFile/runDir instead of compileFile/compileDir to do a run test")
+      "pos"
+    } else "pos"
+  }
 
   /** The three possibilities: no generated sources exist yet, the same sources
     * exist already, different sources exist. */
@@ -184,7 +216,7 @@ abstract class CompilerTest extends DottyTest {
     val flags = oldFlags.map(f => if (f == oldOutput) partestOutput else f)
 
     getExisting(dest).isDifferent(source, flags, nerr) match {
-      case NotExists => copyFiles(source, dest, partestOutput, flags, nerr)
+      case NotExists => copyFiles(source, dest, partestOutput, flags, nerr, kind)
       case ExistsSame => // nothing else to do
       case ExistsDifferent =>
         val nextDest = dest.parent / (dest match {
@@ -195,8 +227,8 @@ abstract class CompilerTest extends DottyTest {
     }
   }
   
-  /** Copies the test sources and creates flags, nerr and output files. */
-  private def copyFiles(sourceFile: Path, dest: Path, partestOutput: String, flags: List[String], nerr: String) = {
+  /** Copies the test sources. Creates flags, nerr, check and output files. */
+  private def copyFiles(sourceFile: Path, dest: Path, partestOutput: String, flags: List[String], nerr: String, kind: String) = {
     recCopyFiles(sourceFile, dest)
 
     new JFile(partestOutput).mkdirs
@@ -205,17 +237,24 @@ abstract class CompilerTest extends DottyTest {
       dest.changeExtension("flags").createFile(true).writeAll(flags.mkString(" "))
     if (nerr != "0")
       dest.changeExtension("nerr").createFile(true).writeAll(nerr)
+    sourceFile.changeExtension("check").ifFile({ check => 
+      if (kind == "run")
+        FileManager.copyFile(check.jfile, dest.changeExtension("check").jfile)
+      else
+        NestUI.echoWarning(s"WARNING: ignoring $check for test kind $kind")
+    })
+
   }
 
-  /** Recursively copy over files and directories, excluding extensions that
-    * aren't in extensionsToCopy. */
+  /** Recursively copy over source files and directories, excluding extensions
+    * that aren't in extensionsToCopy. */
   private def recCopyFiles(sourceFile: Path, dest: Path): Unit = {
     processFileDir(sourceFile, { sf =>
       if (extensionsToCopy.contains(sf.extension)) {
         dest.parent.jfile.mkdirs
         FileManager.copyFile(sourceFile.jfile, dest.jfile)
       } else {
-        println(s"warning: ignoring $sf")
+        NestUI.echoWarning(s"WARNING: ignoring $sf")
       }
     }, { sdir => 
       dest.jfile.mkdirs
diff --git a/tests/partest.lock b/tests/partest.lock
deleted file mode 100644
index e69de29bb2d1..000000000000
diff --git a/tests/run/hello.check b/tests/run/hello.check
new file mode 100644
index 000000000000..6c70cd9e8165
--- /dev/null
+++ b/tests/run/hello.check
@@ -0,0 +1 @@
+hello dotty!
diff --git a/tests/run/hello.scala b/tests/run/hello.scala
new file mode 100644
index 000000000000..9224cec054d3
--- /dev/null
+++ b/tests/run/hello.scala
@@ -0,0 +1,3 @@
+object Test {
+  def main(args: Array[String]): Unit = println("hello dotty!")
+}
diff --git a/tests/run/lazyVals.check b/tests/run/lazyVals.check
new file mode 100644
index 000000000000..f70d7bba4ae1
--- /dev/null
+++ b/tests/run/lazyVals.check
@@ -0,0 +1 @@
+42
\ No newline at end of file
diff --git a/tests/run/lazyVals.scala b/tests/run/lazyVals.scala
new file mode 100644
index 000000000000..db91dbcd6ef2
--- /dev/null
+++ b/tests/run/lazyVals.scala
@@ -0,0 +1,8 @@
+object Test {
+ def foo = {
+   lazy val s = 42 // needs LazyIntHolder
+   s
+  }
+
+  def main(args: Array[String]): Unit = println(foo)
+}