cssd-back/app/Models/TestType.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\HasMany;
use Illuminate\Database\Eloquent\SoftDeletes;

class TestType extends Model
{
    use SoftDeletes;

    public $fillable = ['name', 'unique_code', 'user_id', 'bar_code', 'device_label'];

    public function user(): BelongsTo
    {
        return $this->belongsTo(User::class);
    }

    public function test_results(): HasMany
    {
        return $this->hasMany(TestResult::class);
    }

    public function inputs(): HasMany
    {
        return $this->hasMany(Input::class);
    }
}