Transactions doesn't work on some tests - php

Question

I'm working with Laravel 5.2 and phpunit and i'm writing some test for my application. until now i got no problem, and today i encounter something weird and I can't find a way to handle it.
Some of my test file doesn't use transactions although the others does.
i use use DatabaseTransactions; in my TestCase class with is extended in every test file i got.
Most of my test works without any troubles but some of them does not.
Here is one which works withotut any troubles :
class V2LikeTest extends TestCase {
protected $appToken;
protected $headers;
public function setUp() {
parent::setUp();
$this->generateTopic(1);
}
/** LIKE TOPICS */
/** #test */
public function it_likes_a_topic() {
$job = new ToggleLikeJob(Topic::first());
$job->handle();
$topic = Topic::first();
$this->assertTrue($topic->present()->isLiked);
$this->assertEquals(1, $topic->nb_likes);
}
}
and this one with troubles:
class V2TopicTest extends TestCase {
private $appToken;
private $headers;
public function setUp() {
parent::setUp();
$this->generateCompany(1);
}
/** #test */
public function it_create_a_topic() {
$new_topic_request = new Request([
'content' => str_random(100),
'type' => Topic::TYPE_FEED_TEXT
]);
$job = new CreateFeedTopicJob($new_topic_request->all());
$job->handle();
$this->assertCount(1, Topic::all());
}
}
It's been a while now that i'm looking for the solution but not able to find it. Did someone already meet this troubles?
edit: GenerateTopic function use generateCompany just in case ;)