class User extends Authenticatable
{
    public function address () {
        $this->hasOne(App\Address::class);
    }

    public function test()
    {
        return $this->hasMany(App\Test::class);
    }
}

class Test extends Model
{
    public function user()
    {
        return $this->belongsTo(\App\User::class);
    }

    public function category()
    {
        return $this->hasOne(\App\Category::class);
    }

    public function question()
    {
        return $this->hasMany(\App\Question::class);
    }
}

class Question extends Model
{
    public function test()
    {
        return $this->belongsTo(App\Test::class);
    }

    public function answer()
    {
        return $this->hasMany(App\Answer::class);
    }
}