private String getTestsOutputDir(final Module module) {
   if (myModuleToTestsOutput.containsKey(module)) {
     return myModuleToTestsOutput.get(module);
   }
   final VirtualFile outputDirectory = myCompileContext.getModuleOutputDirectoryForTests(module);
   final String out = outputDirectory != null ? outputDirectory.getPath() : null;
   myModuleToTestsOutput.put(module, out);
   return out;
 }