Is the origin of moon cakes a snack in ancient imperial examinations?

No, in the imperial examination, candidates bring their own dry food, which is not provided in the examination room. The invigilator has to crush the dry food of the candidates to prevent cheating, so candidates should not bring moon cakes. Let's talk about the history of moon cakes:

Moon cakes, also known as Hu cakes, palace cakes, cookies, moon cakes, reunion cakes, etc. It is an offering to worship the moon god in the ancient Mid-Autumn Festival, and the custom of eating moon cakes has been formed since it was handed down. Moon cakes have a long history in China. According to historical records, as early as the Yin and Zhou Dynasties, there was a kind of "Taishi cake" to commemorate Taishi Wenzhong, the "ancestor" of China moon cakes. Zhang Qian introduced sesame seeds and walnuts to the Western Regions in Han Dynasty, which added auxiliary materials for making moon cakes. At this time, a round cake filled with walnuts appeared, which was called "Hu cake". In the Tang Dynasty, people had bakers engaged in production, and pastry shops began to appear in Chang 'an, the capital. It is said that one Mid-Autumn Festival, when Tang Xuanzong and Yang Guifei enjoyed the moon and ate Hu Bing, Tang Xuanzong thought the name Hu Bing was not pleasant to listen to. Yang Guifei looked up at the bright moon, and her heart surged, and she came to "moon cakes" at hand. Since then, the name of "moon cake" has gradually spread among the people. The royal family in the Northern Song Dynasty likes to eat a kind of "palace cake" in the Mid-Autumn Festival, commonly known as "small cake" and "moon group". Su Dongpo has a poem: "Small cakes are like chewing the moon, crisp and pleasing." The screenwriter of the Song Dynasty was thorough. The name "moon cake" was first mentioned in Old Wulin, which described what Lin 'an, the capital of the Southern Song Dynasty, saw. In the Ming Dynasty, eating moon cakes in the Mid-Autumn Festival gradually spread among the people. At that time, ingenious bakers printed the Goddess Chang'e flying to the moon's fairy tales on moon cakes as food art drawings, making moon cakes a necessary food for Mid-Autumn Festival. In the folk, every Mid-Autumn Festival in August, there is the custom of Yue Bai or offering sacrifices to the moon. On August 15th, when the moon is full, Mid-Autumn moon cakes are fragrant and sweet. This famous saying tells the custom that people in cities and rural areas eat moon cakes on the night of Mid-Autumn Festival. At first, moon cakes were used to worship the moon god. Later, people gradually regarded Mid-Autumn Festival as a symbol of family reunion, and mooncakes gradually became holiday gifts.