--- a/mx/mx_graal.py	Fri Dec 13 13:54:13 2013 +0000
+++ b/mx/mx_graal.py	Fri Dec 13 14:26:39 2013 +0000
@@ -808,7 +808,7 @@
         f_testfile.close()
         harness(projectscp, vmArgs)
 
-def _unittest(args, annotations):
+def _unittest(args, annotations, prefixcp=""):
     mxdir = dirname(__file__)
     name = 'JUnitWrapper'
     javaSource = join(mxdir, name + '.java')
@@ -830,9 +830,9 @@
         if len(testclasses) == 1:
             # Execute Junit directly when one test is being run. This simplifies
             # replaying the VM execution in a native debugger (e.g., gdb).
-            vm(prefixArgs + vmArgs + ['-cp', projectscp, 'org.junit.runner.JUnitCore'] + testclasses)
+            vm(prefixArgs + vmArgs + ['-cp', prefixcp + projectscp, 'org.junit.runner.JUnitCore'] + testclasses)
         else:
-            vm(prefixArgs + vmArgs + ['-cp', projectscp + os.pathsep + mxdir, name] + [testfile])
+            vm(prefixArgs + vmArgs + ['-cp', prefixcp + projectscp + os.pathsep + mxdir, name] + [testfile])
 
     try:
         _run_tests(args, harness, annotations, testfile)
@@ -1348,9 +1348,17 @@
 
 def trufflejar(args=None):
     """make truffle.jar"""
+    
+    # Test with the built classes
+    _unittest(["com.oracle.truffle.api.test", "com.oracle.truffle.api.dsl.test"], ['@Test', '@LongTest', '@Parameters'])
+    
     # We use the DSL processor as the starting point for the classpath - this
     # therefore includes the DSL processor, the DSL and the API.
     packagejar(mx.classpath("com.oracle.truffle.dsl.processor").split(os.pathsep), "truffle.jar", None, "com.oracle.truffle.dsl.processor.TruffleProcessor")
+    
+    # Test with the JAR
+    _unittest(["com.oracle.truffle.api.test", "com.oracle.truffle.api.dsl.test"], ['@Test', '@LongTest', '@Parameters'], "truffle.jar:")
+
 
 def isGraalEnabled(vm):
     return vm != 'original' and not vm.endswith('nograal')