Laravel method not recieving post data on $request

On Laravel 5.1 a method is not recivieng the post data.

This is my method where $request does not store the data sent by post.

class ProjectCommentController extends Controller
{
    public function store(Request $request,$projectId)
    {
    $this->validate($request, [
        'description' => ['required'],
        'status' => ['required'],
        'profile_id' => ['required']
    ]);

    $project = Project::findOrFail($projectId);

    return $project->comments()->save(new Comment([
        'description' => $request->input('description'),
        'status' => $request->input('status'),
        'profile_id' => $request->input('profile_id')
    ]));
    }
}

This is how I call it from my test:

public function testProjectCommentCreation()
{
$category = factory(\App\Category::class)->create();

$project = factory(\App\Project::class)->create([
    "category_id" => $category->id
]);

$profile = factory(\App\Profile::class)->create();


$comment = factory(\App\Comment::class)->make([
    "profile_id"=>$profile->id
]);

$this->post(route('api.projects.comments.store', ['projects' => $project->id]), $comment->jsonSerialize(), $this->jsonHeaders)
    ->seeInDatabase('comments', ['project_id'=>$project->id,'description'=>$comment->description])
    ->assertResponseOk();
 }

This is what $comment->jsonSerialize() stores:

array(3) {
'description' =>
string(10) "zFG8bW7EIz"
'status' =>
string(6) "active"
'profile_id' =>
int(629)
}

And this is my route:

Route::resource('projects.comments','ProjectCommentController',['only'=>['index','store']]);

My method recieves $projectId from the URL and that is working but the request comes empty, without the data I send from $comment->jsonSerialize()

via Chebli Mohamed