function obtainClientGrant(APITester $I)
{
$client = factory(App\Models\OAuthClient::class, 1)->create();
$grant = \App\Models\OAuthGrant::find('client_credentials');
$client->oauth_grants()->attach($grant);
$scope = \App\Models\OAuthScope::find('content');
$client->oauth_scopes()->attach($scope);
$I->wantTo('Send client credentials and receive an access token');
$I->haveHttpHeader('Content-Type', 'application/x-www-form-urlencoded');
$I->sendPOST('oauth/access_token', ['grant_type' => 'client_credentials', 'client_id' => $client->id, 'client_secret' => $client->secret, 'scope' => 'content']);
$I->seeResponseCodeIs(200);
$I->seeResponseIsJson();
$I->seeResponseMatchesJsonType(['access_token' => 'string']);
}