Domain\Classroom\ClassroomTest::test_create_classroom_with_matters PHP Method

    public function test_create_classroom_with_matters()
    {
        $classroom = factory(Classroom::class)->create();
        $matter = factory(Matter::class)->create();
        $classroom->matters()->attach($matter);
        $this->assertInstanceOf(Matter::class, $classroom->matters->first());
    }