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Dancer2::Manual::Testing - Writing tests for Dancer2


version 1.1.0

Basic application testing

Since Dancer2 produces PSGI applications, you can easily write tests using Plack::Test and provide your Dancer application as the app for testing.

A basic test (which we also scaffold with dancer2) looks like this:

    use strict;
    use warnings;

    use Test::More tests => 4;
    use Plack::Test;
    use HTTP::Request::Common;


    # create an application
    my $app = MyApp->to_app;
    isa_ok( $app, 'CODE' );

    # create a testing object
    my $test = Plack::Test->create($app);

    # now you can call requests on it and get responses
    # requests are of HTTP::Request
    # responses are of HTTP::Response

    # "GET" from HTTP::Request::Common creates an HTTP::Request object
    my $response = $test->request( GET '/' );

    # same as:
    # my $response = $test->request( HTTP::Request->new( GET => '/' ) );

    ok( $response->is_success, 'Successful request' );
    is( $response->content, 'OK', 'Correct response content' );

Read the documentation for HTTP::Request and HTTP::Request::Common to see the different options for sending parameters.


If you don't want to use an entire user agent for this test, you can use HTTP::Cookies to store cookies and then retrieve them:

    use strict;
    use warnings;

    use Test::More tests => 3;
    use Plack::Test;
    use HTTP::Request::Common;
    use HTTP::Cookies;


    my $url  = 'http://localhost';
    my $jar  = HTTP::Cookies->new();
    my $test = Plack::Test->create( MyApp->to_app );

    subtest 'Create session' => sub {
        my $res = $test->request( GET "$url/login" );
        ok( $res->is_success, 'Successful login' );

        # extract cookies from the response and store in the jar

    subtest 'Check session' => sub {
        my $req = GET "$url/logout";

        # add cookies to the request

        my $res = $test->request($req);
        ok( $res->is_success, 'Successful logout' );
            'Successfully logged out',
            'Got correct log out content',

Please note that the request URL must include scheme and host for the call to "add_cookie_header" in HTTP::Cookies to work.


In order to test plugins, you can create an application on the spot, as part of the test script code, and use the plugin there.

    use strict;
    use warnings;

    use Test::More tests => 2;
    use Plack::Test;
    use HTTP::Request::Common;

        package MyTestApp;
        use Dancer2;
        use Dancer2::Plugin::MyPlugin;

        get '/' => sub { my_keyword };

    my $test = Plack::Test->create( MyTestApp->to_app );
    my $res  = $test->request( GET '/' );

    ok( $res->is_success, 'Successful request' );
    is( $res->content, 'MyPlugin-MyKeyword', 'Correct content' );


Dancer Core Developers


This software is copyright (c) 2023 by Alexis Sukrieh.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.