def testInvalidLengthInPrefix():
prefix = "192.168.1.1/s"
actualResult = question._isPrefix(prefix)
expectMessage = "Prefix length must be an integer"
assert not actualResult[0]
assert expectMessage == actualResult[1]
def testValidPrefix():
prefix = "192.168.1.1/100"
actualResult = question._isPrefix(prefix)
assert actualResult[0]
assert actualResult[1] is None
def testInvalidIpInPrefix():
prefix = "192.168.1.s/100"
actualResult = question._isPrefix(prefix)
expectMessage = "Ip segment is not a number: 's' in ip string: '192.168.1.s'"
assert not actualResult[0]
assert expectMessage == actualResult[1]
