Randomize the test data (YAML properties) in test cases

@xiaohua-guan Thank you for your patch.

Just my two cents, how about this one to create the random IP addresses as follows?

For the following YAML properties,

PublicIpAddress: {{public_ip_address}}
PrivateDnsName: {{private_dns_name}}
CidrBlock: {{cidr_block}}

You can create the random IP addresses as follows (I haven't tested, so please make sure if it works or not)

public_ip = implode('.', [rand(0, 254), rand(0, 255), rand(0, 255), rand(1, 255)]);

private_ip = array_rand([
  implode('.', ['10',  rand(0,  255), rand(0, 255), rand(1, 255)]),
  implode('.', ['172', rand(16,  31), rand(0, 255), rand(1, 255)]),
  implode('.', ['192', '168'        , rand(0, 255), rand(1, 255)]),
]);

cidr_block = array_rand([
  implode('.', ['10' , rand(0,  255), rand(0, 255), rand(1, 255)]) . '/8' ,
  implode('.', ['172', rand(16, 31) , '0'         , '0'         ]) . '/16',
  implode('.', ['192', '168'        , rand(0, 255), '0'         ]) . '/24',
]);

@xiaohua-guan Thank you for the modification. It looks good to me.

@xiaohua-guan and @yas, This patch looks good! Moving to RTBC

@xiaohua-guan and @baldwinlouie Thank you for your contributions. We mark this issue as 'Fixed'.