NAME
Test::LWP::UserAgent - a LWP::UserAgent suitable for simulating and testing network calls
VERSION
version 0.007
SYNOPSIS
In your real code:
use URI;
use HTTP::Request::Common;
use LWP::UserAgent;
my $ua = $self->useragent || LWP::UserAgent->new;
my $uri = URI->new('http://example.com');
$uri->port(3000);
$uri->path('success');
my $request = POST($uri, a => 1);
my $response = $ua->request($request);Then, in your tests:
use Test::LWP::UserAgent;
use Test::More;
Test::LWP::UserAgent->map_response(
qr{example.com/success}, HTTP::Response->new(200, 'OK', ['Content-Type' => 'text/plain'], ''));
Test::LWP::UserAgent->map_response(
qr{example.com/fail}, HTTP::Response->new(500, 'ERROR', ['Content-Type' => 'text/plain'], ''));
Test::LWP::UserAgent->map_response(
qr{example.com/conditional},
sub {
my $request = shift;
my $success = $request->uri =~ /success/;
return HTTP::Response->new(
($success ? ( 200, 'OK') : (500, 'ERROR'),
['Content-Type' => 'text/plain'], '')
)
},
);OR, you can use a PSGI app to handle the requests:
use HTTP::Message::PSGI;
Test::LWP::UserAgent->register_psgi('example.com' => sub {
my $env = shift;
# logic here...
[ 200, [ 'Content-Type' => 'text/plain' ], [ 'some body' ] ],
);And then:
# <something which calls the code being tested...>
my $last_request = Test::LWP::UserAgent->last_http_request_sent;
is($last_request->uri, 'http://example.com/success:3000', 'URI');
is($last_request->content, 'a=1', 'POST content');
# <now test that your code responded to the 200 response properly...>One common mechanism to swap out the useragent implementation is via a lazily-built Moose attribute; if no override is provided at construction time, default to LWP::UserAgent->new(%options).
METHODS
All methods may be called on a specific object instance, or as a class method. If called as on a blessed object, the action performed or data returned is limited to just that object; if called as a class method, the action or data is global.
map_response($request_description, $http_response)-
With this method, you set up what HTTP::Response should be returned for each request received.
The request match specification can be described in multiple ways:
- string
-
The string is matched identically against the
hostfield of the URI in the request.Example:
$test_ua->map_response('example.com', HTTP::Response->new(500)); - regexp
-
The regexp is matched against the URI in the request.
Example:
$test_ua->map_response(qr{foo/bar}, HTTP::Response->new(200)); $test_ua->map_response(qr{baz/quux}, HTTP::Response->new(500)); - code
-
An arbitrary coderef is passed a single argument, the HTTP::Request, and returns a boolean indicating if there is a match.
$test_ua->map_response(sub { my $request = shift; return 1 if $request->method eq 'GET' || $request->method eq 'POST'; }, HTTP::Response->new(200), ); - HTTP::Request object
-
The HTTP::Request object is matched identically (including all query parameters, headers etc) against the provided object.
The response can be represented either as a literal HTTP::Request object, or as a coderef that is run at the time of matching, with the request passed as the single argument:
HTTP::Response->new(...);or
sub { my $request = shift; HTTP::Response->new(...); }Instance mappings take priority over global (class method) mappings - if no matches are found from mappings added to the instance, the global mappings are then examined. After no matches have been found, a 404 response is returned.
unmap_all(instance_only?)-
When called as a class method, removes all mappings set up globally (across all objects). Mappings set up on an individual object will still remain.
When called as an object method, removes all mappings both globally and on this instance, unless a true value is passed as an argument, in which only mappings local to the object will be removed. (Any true value will do, so you can pass a meaningful string.)
register_psgi($domain, $app)-
Register a particular PSGI app (code reference) to be used when requests for a domain are received (matches are made exactly against
$request->uri->host). The request is passed to the$appfor processing, and the PSGI response is converted back to an HTTP::Response (you must already have loaded HTTP::Message::PSGI or equivalent, as this is not done for you).You can also use
register_psgiwith a regular expression as the first argument, or any of the other forms used bymap_response, if you wish, as calling$test_ua->register_psgi($domain, $app)is equivalent to:$test_ua->map_response( $domain, sub { HTTP::Response->from_psgi($app->($_[0]->to_psgi)) }, ); unregister_psgi($domain, instance_only?)-
When called as a class method, removes a domain->PSGI app entry that had been registered globally. Some mappings set up on an individual object may still remain.
When called as an object method, removes a domain registration that was made both globally and locally, unless a true value was passed as the second argument, in which case only the registration local to the object will be removed. This allows a different mapping made globally to take over.
If you want to mask a global registration on just one particular instance, then add
undefas a mapping on your instance:$useragent->map_response($domain, undef); last_http_request_sent-
The last HTTP::Request object that this object (if called on an object) or module (if called as a class method) processed, whether or not it matched a mapping you set up earlier.
last_http_response_received-
The last HTTP::Response object that this module returned, as a result of a mapping you set up earlier with
map_response. You shouldn't normally need to use this, as you know what you responded with - you should instead be testing how your code reacted to receiving this response. send_request($request)-
This is the only method from LWP::UserAgent that has been overridden, which processes the HTTP::Request, sends to the network, then creates the HTTP::Response object from the reply received. Here, we loop through your local and global domain registrations, and local and global mappings (in this order) and returns the first match found; otherwise, a simple 404 response is returned.
All other methods from LWP::UserAgent are available unchanged.
MOTIVATION
Most mock libraries on the CPAN use Test::MockObject, which is widely considered not good practice (among other things, @ISA is violated, it requires knowing far too much about the module's internals, and is very clumsy to work with).
This module is a direct descendant of LWP::UserAgent, exports nothing into your namespace, and all access is via method calls, so it is fully inheritable should you desire to add more features or override some bits of functionality.
(Aside from the constructor), it only overrides the one method in LWP::UserAgent that issues calls to the network, so real HTTP::Request and HTTP::Headers objects are used throughout. It provides a method (last_http_request_sent) to access the last HTTP::Request, for testing things like the URI and headers that your code sent to LWP::UserAgent.
TODO (possibly)
- Option to locally or globally override useragent implementations via symbol table swap
- Ability to route certain requests through the real network, to gain the benefits of
last_http_request_sentandlast_http_response_received
ACKNOWLEDGEMENTS
AirG Inc., my employer, and the first user of this distribution.
mst - Matt S. Trout <mst@shadowcat.co.uk>, for the better name of this distribution, and for the PSGI registration concept.
Also Yury Zavarin, whose Test::Mock::LWP::Dispatch inspired me to write this module, and from where I borrowed some aspects of the API.
SEE ALSO
COPYRIGHT
This software is copyright (c) 2012 by Karen Etheridge, <ether@cpan.org>.
LICENSE
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.