Since the popularization of social media, news has entered our lives digitally. While news is spreading broader and faster, fake news is becoming an increasingly popular topic. Fake news detection is therefore important in both social media and research areas. With artificial intelligence technology, software engineers have developed a lot of fake news detection systems. One of the biggest challenges for such systems is that they may face the oracle problem, which means that there may not be a way, or it may take too long time, to confirm the correctness of a specific output. Metamorphic Testing has been applied successfully to alleviate the oracle problem in many different areas, including in artificial intelligence. In this paper, we propose several metamorphic relations for fake news detection and report on experiments using metamorphic testing on fake news detection applications.