### Question:
AdvertisingPacketFactoryManager { public AdvertisingPacketFactory getAdvertisingPacketFactory(byte[] advertisingData) { AdvertisingPacketFactory factory = null; for (AdvertisingPacketFactory advertisingPacketFactory : advertisingPacketFactories) { factory = advertisingPacketFactory.getAdvertisingPacketFactory(advertisingData); if (factory != null) { break; } } return factory; } AdvertisingPacketFactoryManager(); AdvertisingPacket createAdvertisingPacket(byte[] advertisingData); AdvertisingPacketFactory getAdvertisingPacketFactory(byte[] advertisingData); void addAdvertisingPacketFactory(AdvertisingPacketFactory advertisingPacketFactory); List<AdvertisingPacketFactory> getAdvertisingPacketFactories(); void setAdvertisingPacketFactories(List<AdvertisingPacketFactory> advertisingPacketFactories);  }### Answer:
@Test public void getAdvertisingPacketFactory_defaultFactories_returnsNull() throws Exception { AdvertisingPacketFactory factory = advertisingPacketFactoryManager.getAdvertisingPacketFactory(new byte[]{}); assertNull(factory); }