python 代码题02 使用迭代查找一个list中最小和最大值，并返回一个tuple

def findMinAndMax(L):
	if L!=[]:
		min = L[0]
		max = L[0]
		for i in L:
			if max < i:
				max = i
			if min > i :
				min = i
		return(min, max)
	else: return (None, None)
	
# 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!')