Domain\Matter\MatterTest::test_create_matter_with_lessons PHP Method

    public function test_create_matter_with_lessons()
    {
        $matter = factory(Matter::class)->create();
        $lesson = factory(Lesson::class)->create();
        $matter->lessons()->attach($lesson);
        $this->assertInstanceOf(Matter::class, $matter);
        $this->assertInstanceOf(Lesson::class, $matter->lessons->first());
    }