NAME

Test::TCP - testing TCP program

SYNOPSIS

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
    },
);

DESCRIPTION

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

METHODS

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.

Object Oriented interface

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.

FAQ

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 `Net::EmptyPort::can_bind` 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',
);

AUTHOR

Tokuhiro Matsuno <tokuhirom@gmail.com>

THANKS TO

kazuhooku

dragon3

charsbar

Tatsuhiko Miyagawa

lestrrat

SEE ALSO

LICENSE

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