fromtcpdump.t fails because Net::DNS::Packet doesn't provide TO_JSON

[tsibley]

JSON::XS is configured to allow blessed objects and convert them if a TO_JSON method is available. If TO_JSON is not available, however, the object is replaced by a JSON null.

I'm not sure if I should just adjust the test or if I should monkey patch TO_JSON methods into Net::DNS::Packet and related packages so that they JSON-ify as expected by RecordStream.

For example, RecordStream could do this:

sub Net::DNS::Packet::TO_JSON {
    { %{ $_[0] } }
}

although ideally it would be localized to avoid side-effects in other code:

local *Net::DNS::Packet::TO_JSON = sub {
    ....
};

Full test output below:

tom@whaam RecordStream (master=) $ prove -wlv tests/RecordStream//Operation/fromtcpdump.t 
tests/RecordStream//Operation/fromtcpdump.t .. 
ok 1 - use App::RecordStream::Operation::fromtcpdump;
ok 2 - Operation initialization
ok 3 - Record is a App::RecordStream::Record
ok 4 - Record is a App::RecordStream::Record
not ok 5 - Records match: unnamed

#   Failed test 'Records match: unnamed'
#   at /home/tom/projects/RecordStream/lib/App/RecordStream/Test/OperationHelper.pm line 104.
#     Structures begin differing at:
#          $got->[0]{dns}{count} = ARRAY(0x19b6618)
#     $expected->[0]{dns}{count} = Does not exist
ok 6 - Has called finish: unnamed
1..6
Expected and output differed!
Expected:
{"dns":{"answer":[],"buffer":"","question":[{"qclass":"IN","qname":"blog.benjaminbernard.com","qtype":"A"}],"answersize":42,"additional":[],"authority":[],"header":{"cd":0,"nscount":0,"qdcount":1,"ancount":0,"rcode":"NOERROR","tc":0,"opcode":"QUERY","ad":0,"ra":0,"qr":0,"id":3930,"arcount":0,"aa":0,"rd":1},"offset":42},"ip":{"len":70,"hlen":5,"dest_ip":"10.0.0.1","proto":17,"options":"","foffset":0,"flags":{},"ttl":64,"ver":4,"src_ip":"10.0.2.15","cksum":10544,"tos":0,"id":15208},"file":"tests/files/test-capture1.pcap","caplen":84,"length":84,"timestamp":"1294004869.88858","ethernet":{"dest_mac":"525400123502","src_mac":"080027e0fd58"},"udp":{"len":50,"src_port":46578,"cksum":5715,"dest_port":53},"type":"udp"}
{"dns":{"answer":[{"rdlength":4,"ttl":1800,"name":"blog.benjaminbernard.com","type":"A","class":"IN","address":"63.251.171.81","rdata":""},{"rdlength":4,"ttl":1800,"name":"blog.benjaminbernard.com","type":"A","class":"IN","address":"69.25.27.170","rdata":""},{"rdlength":4,"ttl":1800,"name":"blog.benjaminbernard.com","type":"A","class":"IN","address":"63.251.171.80","rdata":""},{"rdlength":4,"ttl":1800,"name":"blog.benjaminbernard.com","type":"A","class":"IN","address":"69.25.27.173","rdata":""},{"rdlength":4,"ttl":1800,"name":"blog.benjaminbernard.com","type":"A","class":"IN","address":"66.150.161.141","rdata":""},{"rdlength":4,"ttl":1800,"name":"blog.benjaminbernard.com","type":"A","class":"IN","address":"66.150.161.140","rdata":""}],"buffer":"","question":[{"qclass":"IN","qname":"blog.benjaminbernard.com","qtype":"A"}],"answersize":138,"additional":[],"authority":[],"header":{"cd":0,"nscount":0,"qdcount":1,"ancount":6,"rcode":"NOERROR","tc":0,"opcode":"QUERY","ad":0,"ra":1,"qr":1,"id":3930,"arcount":0,"aa":0,"rd":1},"offset":138},"ip":{"len":166,"hlen":5,"dest_ip":"10.0.2.15","proto":17,"options":"","foffset":0,"flags":{},"ttl":64,"ver":4,"src_ip":"10.0.0.1","cksum":23131,"tos":0,"id":2525},"file":"tests/files/test-capture1.pcap","caplen":180,"length":180,"timestamp":"1294004869.160748","ethernet":{"dest_mac":"080027e0fd58","src_mac":"525400123500"},"udp":{"len":146,"src_port":53,"cksum":47199,"dest_port":46578},"type":"udp"}
Output from module:
{"dns":null,"ip":{"hlen":5,"len":70,"proto":17,"dest_ip":"10.0.0.1","flags":{},"foffset":0,"options":"","ttl":64,"ver":4,"cksum":10544,"src_ip":"10.0.2.15","tos":0,"id":15208},"file":"tests/files/test-capture1.pcap","caplen":84,"length":84,"timestamp":"1294004869.88858","ethernet":{"src_mac":"080027e0fd58","dest_mac":"525400123502"},"udp":{"len":50,"src_port":46578,"dest_port":53,"cksum":5715},"type":"udp"}
{"dns":null,"ip":{"hlen":5,"len":166,"proto":17,"dest_ip":"10.0.2.15","flags":{},"foffset":0,"options":"","ttl":64,"ver":4,"cksum":23131,"src_ip":"10.0.0.1","tos":0,"id":2525},"file":"tests/files/test-capture1.pcap","caplen":180,"length":180,"timestamp":"1294004869.160748","ethernet":{"src_mac":"525400123500","dest_mac":"080027e0fd58"},"udp":{"len":146,"src_port":53,"dest_port":46578,"cksum":47199},"type":"udp"}
# Looks like you failed 1 test of 6.
Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/6 subtests 

Test Summary Report
-------------------
tests/RecordStream//Operation/fromtcpdump.t (Wstat: 256 Tests: 6 Failed: 1)
  Failed test:  5
  Non-zero exit status: 1
Files=1, Tests=6,  0 wallclock secs ( 0.02 usr  0.00 sys +  0.07 cusr  0.00 csys =  0.09 CPU)
Result: FAIL

[benbernard]

sigh fromtcpdump was a script I needed a couple of times back when I was doing a lot of latency analysis, I'm not sure we even need to keep it. I think this is a change in behavior from Net::DNS::Packet, because I definitely used this a bunch like 2-3 years ago. I'm cool with just skipping fromtcpdump work for now (disabling the test). If you want to fix it (would would, of course, be awesome), I'd say we should do the local monkey patch, or just post process the objects ourselves, though that can be a little crazy...

[tsibley]

Hmm. Digging into the history of Net-DNS and RecordStream, I'm not sure how the test ever worked. The internal structures of Net::DNS::Packet don't match those in the expected JSON, i.e. the objects appear carefully massaged either by hand or by code that's vanished entirely.

Regardless, I've just gone and marked the test todo skip. Pull request ahoy!