def findMinAndMax(list1):
    if list1==[]:
        return None,None
    list_max=list1[0]
    list_min=list1[0]
    for i in range(len(list1)):
        if list1[i]>list_max:
            list_max=list1[i]
    for i in range(len(list1)):
        if list1[i]<list_min:
            list_min=list1[i]
    return list_min,list_max


# 测试
if findMinAndMax([]) != (None, None):
    print('测试失败!')
elif findMinAndMax([7]) != (7, 7):
    print('测试失败!')
elif findMinAndMax([7, 1]) != (1, 7):
    print('测试失败!')
elif findMinAndMax([7, 1, 3, 9, 5]) != (1, 9):
    print('测试失败!')
else:
    print('测试成功!')