Program: 64123
Project: 64123
Buggy source:
@Test public void testJunitOnMpArguments() throws Exception {
  final File tmp=new File(System.getProperty("String_Node_Str"));
  final File workDir=new File(tmp,String.format("String_Node_Str",getClass().getName(),System.currentTimeMillis() / 1000));
  workDir.mkdirs();
  try {
    final File modulesDir=new File(workDir,"String_Node_Str");
    modulesDir.mkdirs();
    final Project project=new Project();
    project.init();
    project.setBaseDir(workDir);
    final MockCommandLauncher mockProcLauncher=new MockCommandLauncher();
    project.addReference(MagicNames.ANT_VM_LAUNCHER_REF_ID,mockProcLauncher);
    JUnitTask task=new JUnitTask();
    task.setDir(workDir);
    task.setFork(true);
    task.setProject(project);
    final File junit=LoaderUtils.getResourceSource(JUnitTask.class.getClassLoader(),"String_Node_Str");
    final Path mp=new Path(project);
    mp.add(new Path(project,junit.getAbsolutePath()));
    mp.add(new Path(project,modulesDir.getName()));
    task.createModulepath().add(mp);
    task.addTest(new JUnitTest("String_Node_Str"));
    task.execute();
    assertNotNull(mockProcLauncher.cmd);
    String resCp=null;
    String resMp=null;
    Set<String> resExports=new TreeSet<String>();
    for (int i=1; i < mockProcLauncher.cmd.length; i++) {
      if ("String_Node_Str".equals(mockProcLauncher.cmd[i])) {
        resCp=mockProcLauncher.cmd[++i];
      }
 else       if ("String_Node_Str".equals(mockProcLauncher.cmd[i])) {
        resMp=mockProcLauncher.cmd[++i];
      }
 else       if (mockProcLauncher.cmd[i].equals("String_Node_Str")) {
        resExports.add(mockProcLauncher.cmd[++i]);
      }
 else       if (JUnitTestRunner.class.getName().equals(mockProcLauncher.cmd[i])) {
        break;
      }
    }
    assertTrue("String_Node_Str",resExports.isEmpty());
    assertNull("String_Node_Str",resCp);
    assertEquals("String_Node_Str",mp.toString(),resMp);
  }
  finally {
    delete(workDir);
  }
}

Fixed version (ground truth):
@Test public void testJunitOnMpArguments() throws Exception {
  final File tmp=new File(System.getProperty("String_Node_Str"));
  final File workDir=new File(tmp,String.format("String_Node_Str",getClass().getName(),System.currentTimeMillis() / 1000));
  workDir.mkdirs();
  try {
    final File modulesDir=new File(workDir,"String_Node_Str");
    modulesDir.mkdirs();
    final Project project=new Project();
    project.init();
    project.setBaseDir(workDir);
    final MockCommandLauncher mockProcLauncher=new MockCommandLauncher();
    project.addReference(MagicNames.ANT_VM_LAUNCHER_REF_ID,mockProcLauncher);
    JUnitTask task=new JUnitTask();
    task.setDir(workDir);
    task.setFork(true);
    task.setProject(project);
    final File junit=LoaderUtils.getResourceSource(JUnitTask.class.getClassLoader(),"String_Node_Str");
    final Path mp=new Path(project);
    mp.add(new Path(project,junit.getAbsolutePath()));
    mp.add(new Path(project,modulesDir.getName()));
    task.createModulepath().add(mp);
    task.addTest(new JUnitTest("String_Node_Str"));
    task.execute();
    assertNotNull(mockProcLauncher.cmd);
    String resCp=null;
    String resMp=null;
    Set<String> resExports=new TreeSet<String>();
    for (int i=1; i < mockProcLauncher.cmd.length; i++) {
      if ("String_Node_Str".equals(mockProcLauncher.cmd[i])) {
        resCp=mockProcLauncher.cmd[++i];
      }
 else       if ("String_Node_Str".equals(mockProcLauncher.cmd[i])) {
        resMp=mockProcLauncher.cmd[++i];
      }
 else       if (mockProcLauncher.cmd[i].equals("String_Node_Str")) {
        resExports.add(mockProcLauncher.cmd[++i]);
      }
 else       if (JUnitTestRunner.class.getName().equals(mockProcLauncher.cmd[i])) {
        break;
      }
    }
    assertTrue("String_Node_Str",resExports.isEmpty());
    if (System.getProperty(MagicNames.BUILD_SYSCLASSPATH) == null) {
      assertNull("String_Node_Str",resCp);
    }
    assertEquals("String_Node_Str",mp.toString(),resMp);
  }
  finally {
    delete(workDir);
  }
}