How to implement Functional Test in Symfony 4 with Kahlan 4

In this tutorial, we are going to discuss about how to implement the functional testing in Symfony 4 with Kahlan 4. In IT world, whenever we are creating an application/website, we need to test the application/website thouroghly. To perform the functional testing we have a bundle in Symfony 4. 

The simplest way is define Symfony 4 skeleton bootstrap in kahlan config, and use its property at specs, for example, we configure config at kahlan-config.php as follows:

suite()->root();
    $root->beforeAll(function () {
        $this->request = Request::createFromGlobals();
        $this->kernel  = new Kernel('test', false);
    });
    return $next();
});

Above settings are minimal, if you need more setup, you can define there. If you didn’t require kahlan/kahlan:^4.0, you can require via composer:

$ composer require --dev kahlan/kahlan:^4.0

Give a try

Let’s try testing a famous /lucky/number from LuckyController. We have the following controller:

render('lucky/number.html.twig', [
            'number' => $number,
        ]);
    }
}

And our twig file is:

{# templates/lucky/number.html.twig #}
<h1>Your lucky number is {{ number }}</h1>

We can place test under spec directory at root directory, for its test, we can create a spec/Controller directory:

kahlan.config.php
    spec
        Controller

Now, we can create the test as follows with make request to the ‘/lucky/number’ page and get its response. We can use toMatchEcho matcher provided with regex to get match random number of mt_rand(0, 100) that printed inside a response html content:

request->create('/lucky/number', 'GET');
            $response = $this->kernel->handle($request);
 
            expect(function () use ($response) {
                $response->send();
            })->toMatchEcho(
                "#Your lucky number is ([0-9]|[1-8][0-9]|9[0-9]|100)#"
            );
 
        });
 
    });
 
});

Time to run it with command:

$ vendor/bin/kahlan 

By running the above commmand, you will get an Output.