fix: whereBelongsTo (#2454)

* override getQualifiedForeignKeyName() and add tests for whereBelongsTo

* delete unneeded query() call

* type hint for getQualifiedForeignKeyName()

Co-authored-by: Hikmat Hasanov <hikmet.hasanov@proton.me>

src/Relations/BelongsTo.php

@@ -72,4 +72,9 @@ protected function whereInMethod(EloquentModel $model, $key)
     {
         return 'whereIn';
     }
+
+    public function getQualifiedForeignKeyName(): string
+    {
+        return $this->foreignKey;
+    }
 }

tests/RelationsTest.php

@@ -534,4 +534,17 @@ public function testDoubleSaveManyToMany(): void
         $this->assertEquals([$user->_id], $client->user_ids);
         $this->assertEquals([$client->_id], $user->client_ids);
     }
+
+    public function testWhereBelongsTo()
+    {
+        $user = User::create(['name' => 'John Doe']);
+        Item::create(['user_id' => $user->_id]);
+        Item::create(['user_id' => $user->_id]);
+        Item::create(['user_id' => $user->_id]);
+        Item::create(['user_id' => null]);
+
+        $items = Item::whereBelongsTo($user)->get();
+
+        $this->assertCount(3, $items);
+    }
 }