code: public static void setDbFile(final File dbFile, final String[] devices, final String className) throws DevFailed {
          DatabaseFactory.useDb = false;
          DatabaseFactory.fileDatabase = new FileTangoDB(dbFile, Arrays.copyOf(devices, devices.length), className);
      }
docs: Build a mock tango db with a file containing the properties
  
  @param dbFile
  @param devices
  @param classes
  @throws DevFailed