考is short for 考试 in some situations I have a Chinese test tomorrow 我明天要考汉语。 or 我明天有一场汉语考试 考 is a verb and often means "考察" but 考试 is usually a noun. ex:快考试了,大家抓紧(时间) 复习. 我们明天考汉语,后天考英语. hope it can help you

你可以说：“我明天有一个中文考试。”

考 is a transitive verb, while 考试 can be used as an intransitive verb or a noun. "I have a Chinese test tomorrow." = 我明天要考中文/汉语. or 我明天有中文/汉语考试.

明天 我 有 汉语 考试。