browser: Json::assertHas doesn't work as expected

Hi,

I just updated the library in my project to latest version (1.2) and replaced some places to use KernelBrowser::browser()->json()->assertHas('selector'). But it seems that it doesn’t work as expected.

I’m testing a json api endpoint which returns this json:

{
  "limit": 50,
  "total": 1,
  "page": 1,
  "pages", 1,
  "_links": {
    "first": {
      "href": "/api/backend/chains?_page=1&_per_page=50"
    },
    "last": {
      "href": "/api/backend/chains?_page=1&_per_page=50"
    }
  }
  "_embedded": {
    "items": [
         {"id": 1, "label": "Grand compte par défaut"}
    ]
  }
}

Here is my test which fails:

$this->browser()->get('/uri')->assertStatus(Response::RESPONSE_OK)
    ->json()->assertHas('total');

Here is my test which succeeds:

$response = $this->browser()->get('/uri')->assertStatus(Response::RESPONSE_OK)
    ->json()->decoded();
self::assertSame(1, $response['total']);

I tried to replace the Assert::try in Json::assertHas by Assert::that($selector)->isNotEmpty() and it works. I think the problem comes from length used which in this case returns something empty as 1 is not countable… I don’t know if my solution is the best to use. If so, let me know I can provide the PR. 😃

Thank you