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<div class="pod-document"><h1><a name="testing_dancer_with_test__mojo"></a>Testing Dancer with Test::Mojo</h1>

<p>Authors of Dancer (and other) PSGI applications are probably accustomed to <a href="https://metacpan.org/pod/distribution/Dancer2/lib/Dancer2/Manual.pod#TESTING">testing</a> with <a href="https://metacpan.org/pod/Plack::Test">Plack::Test</a>, and ...
<p>During advent last year, I wrote about <a href="https://mojolicious.org/perldoc/Test/Mojo">Test::Mojo</a>, showing the many easy and (dare I say) fun ways that you can use it to test your Mojolicious applications.
If you missed it, go <a href="https://mojolicious.io/blog/2017/12/09/day-9-the-best-way-to-test/">check it out</a>.</p>
<p>I expect there are at least a few of you out there who read that and think, "I'd love to use that, but I don't use Mojolicious!"; well, you're in luck!
With just a little role to bridge the gap, you can use Test::Mojo to test your PSGI applications too!</p>
<h2><a name="mounting_psgi_applications"></a>Mounting PSGI Applications</h2>

<p>Mojolicious itself doesn't use the <a href="https://metacpan.org/pod/PSGI">PSGI</a> protocol, owing to certain features that it doesn't provide and which are necessary for certain asynchronous operations.
That said, you can serve a Mojolicious application on a PSGI server by using <a href="https://mojolicious.org/perldoc/Mojo/Server/PSGI">Mojo::Server::PSGI</a>.
This Mojolicious-core module is automatically used for you when your Mojolicious-based app detects that it has started under a PSGI server (e.g. plackup or Starman).</p>
<p>While translating between a Mojo app and a PSGI server is core functionality, doing the opposite, translating between a PSGI app and a Mojolicious server (or app, as you'll see) is available as a third party module.
<a href="https://metacpan.org/pod/Mojolicious::Plugin::MountPSGI">Mojolicious::Plugin::MountPSGI</a>, as it's name implies, can mount a PSGI application into a Mojolicious-based one.
To do so, it builds a new, empty Mojolicious application that translates all requests to PSGI environments before dispatching to it as with any <a href="https://mojolicious.org/perldoc/Mojolicious/Plugin/Mount">mount</a>-ed application.</p>
<h2><a name="testing_using_test__mojo"></a>Testing using Test::Mojo</h2>

<p>Once you can do that, it is trivial to take a PSGI application, wrap it with MountPSGI, and set it as the application for use with Test::Mojo.
Still, to make it even easier, that has all been done for you in <a href="https://metacpan.org/pod/Test::Mojo::Role::PSGI">Test::Mojo::Role::PSGI</a>.</p>
<p>Like any <a href="https://mojolicious.io/blog/2017/12/13/day-13-more-about-roles/">Mojolicious Role</a>, we can use <code>with_roles</code> to create a (mostly anonymous) subclass with the role applied.