Test::TCP - testing TCP program

use Test::TCP;

my $server = Test::TCP->new(
    listen => 1,
    code => sub {
        my $socket = shift;
        ...
    },
);
my $client = MyClient->new(host => '127.0.0.1', port => $server->port);
undef $server; # kill child process on DESTROY

If using a server that can only accept a port number, e.g. memcached:

use Test::TCP;

my $memcached = Test::TCP->new(
    code => sub {
        my $port = shift;

        exec $bin, '-p' => $port;
        die "cannot execute $bin: $!";
    },
);
my $memd = Cache::Memcached->new({servers => ['127.0.0.1:' . $memcached->port]});
...

N.B.: This is vulnerable to race conditions, if another process binds to the same port after Net::EmptyPort found it available.

And functional interface is available:

use Test::TCP;
test_tcp(
    listen => 1,
    client => sub {
        my ($port, $server_pid) = @_;
        # send request to the server
    },
    server => sub {
        my $socket = shift;
        # run server, calling $socket->accept
    },
);

test_tcp(
    client => sub {
        my ($port, $server_pid) = @_;
        # send request to the server
    },
    server => sub {
        my $port = shift;
        # run server, binding to $port
    },
);

Test::TCP is a test utility to test TCP/IP-based server programs.

• test_tcp

  Functional interface.

    test_tcp(
        listen => 1,
        client => sub {
            my $port = shift;
            # send request to the server
        },
        server => sub {
            my $socket = shift;
            # run server
        },
        # optional
        host => '127.0.0.1', # specify '::1' to test using IPv6
        port => 8080,
        max_wait => 3, # seconds
    );
  

  If listen is false, server is instead passed a port number that was free before it was called.

• wait_port

    wait_port(8080);
  

  Waits for a particular port is available for connect.

• my $server = Test::TCP->new(%args);

  Create new instance of Test::TCP.

  Arguments are following:

  • $args{auto_start}: Boolean

    Call $server->start() after create instance.

    Default: true

  • $args{code}: CodeRef

    The callback function. Argument for callback function is: $code->($socket) or $code->($port), depending on the value of listen.

    This parameter is required.

  • $args{max_wait} : Number

    Will wait for at most $max_wait seconds before checking port.

    See also Net::EmptyPort.

    Default: 10

  • $args{listen} : Boolean

    If true, open a listening socket and pass this to the callback. Otherwise find a free port and pass the number of it to the callback.

• $server->start()

  Start the server process. Normally, you don't need to call this method.

• $server->stop()

  Stop the server process.

• my $pid = $server->pid();

  Get the pid of child process.

• my $port = $server->port();

  Get the port number of child process.

• How to invoke two servers?

  You can call test_tcp() twice!

    test_tcp(
        client => sub {
            my $port1 = shift;
            test_tcp(
                client => sub {
                    my $port2 = shift;
                    # some client code here
                },
                server => sub {
                    my $port2 = shift;
                    # some server2 code here
                },
            );
        },
        server => sub {
            my $port1 = shift;
            # some server1 code here
        },
    );
  

  Or use the OO interface instead.

    my $server1 = Test::TCP->new(code => sub {
        my $port1 = shift;
        ...
    });
    my $server2 = Test::TCP->new(code => sub {
        my $port2 = shift;
        ...
    });
  
    # your client code here.
    ...
  

• How do you test server program written in other languages like memcached?

  You can use exec() in child process.

    use strict;
    use warnings;
    use utf8;
    use Test::More;
    use Test::TCP 1.08;
    use File::Which;
  
    my $bin = scalar which 'memcached';
    plan skip_all => 'memcached binary is not found' unless defined $bin;
  
    my $memcached = Test::TCP->new(
        code => sub {
            my $port = shift;
  
            exec $bin, '-p' => $port;
            die "cannot execute $bin: $!";
        },
    );
  
    use Cache::Memcached;
    my $memd = Cache::Memcached->new({servers => ['127.0.0.1:' . $memcached->port]});
    $memd->set(foo => 'bar');
    is $memd->get('foo'), 'bar';
  
    done_testing;
  

• How do I use address other than "127.0.0.1" for testing?

  You can use the host parameter to specify the bind address.

    # let the server bind to "0.0.0.0" for testing
    test_tcp(
        client => sub {
            ...
        },
        server => sub {
            ...
        },
        host => '0.0.0.0',
    );
  

• How should I write IPv6 tests?

  You should use the "can_bind" in Net::EmptyPort function to check if the program can bind to the loopback address of IPv6, as well as the host parameter of the "test_tcp" function to specify the same address as the bind address.

    use Net::EmptyPort qw(can_bind);
  
    plan skip_all => "IPv6 not available"
        unless can_bind('::1');
  
    test_tcp(
        client => sub {
            ...
        },
        server => sub {
            ...
        },
        host => '::1',
    );
  

Tokuhiro Matsuno tokuhirom@gmail.com

kazuhooku

dragon3

charsbar

Tatsuhiko Miyagawa

lestrrat

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.