app/Models/RoomUser.php

@@ -9,6 +9,9 @@ use Illuminate\Database\Eloquent\Relations\BelongsTo;
 class RoomUser extends Model
 {
     protected $table = 'room_user';
+
+    protected $guarded = [];
+
     public function user(): BelongsTo
     {
         return $this->belongsTo(User::class);
@@ -16,7 +19,7 @@ class RoomUser extends Model
 
     public function judge(): BelongsTo
     {
-        return $this->belongsTo(User::class);
+        return $this->belongsTo(User::class, 'user_id');
     }
 
     public function room(): BelongsTo

tests/Feature/Models/RoomUserTest.php

@@ -0,0 +1,26 @@
+<?php
+
+use App\Models\Room;
+use App\Models\RoomUser;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+
+uses(RefreshDatabase::class);
+
+beforeEach(function () {
+    $this->user = User::factory()->create();
+    $this->room = Room::factory()->create();
+    $this->roomUser = RoomUser::create(['user_id' => $this->user->id, 'room_id' => $this->room->id]);
+});
+
+it('has a user', function () {
+    expect($this->roomUser->user->first_name)->toBe($this->user->first_name);
+});
+
+it('has a judge', function () {
+    expect($this->roomUser->judge->first_name)->toBe($this->user->first_name);
+});
+
+it('has a room', function () {
+    expect($this->roomUser->room->name)->toBe($this->room->name);
+});