Ensure Eloquent\Collection returned after filtering (#354)

* Ensure Eloquent\Collection returned after filtering

* Add test to assert Database\Collection returned

src/ElasticEngine.php

@@ -315,7 +315,7 @@ public function map(Builder $builder, $results, $model)
             ->get($columns)
             ->keyBy($scoutKeyName);
 
-        return Collection::make($results['hits']['hits'])
+        $values = Collection::make($results['hits']['hits'])
             ->map(function ($hit) use ($models) {
                 $id = $hit['_id'];
 
@@ -331,6 +331,8 @@ public function map(Builder $builder, $results, $model)
             })
             ->filter()
             ->values();
+
+        return $values instanceof Collection ? $values : Collection::make($values);
     }
 
     /**

tests/ElasticEngineTest.php

@@ -2,6 +2,7 @@
 
 namespace ScoutElastic\Tests;
 
+use Illuminate\Database\Eloquent\Collection;
 use ScoutElastic\Builders\FilterBuilder;
 use ScoutElastic\Builders\SearchBuilder;
 use ScoutElastic\ElasticEngine;
@@ -440,6 +441,82 @@ public function testMapWithTrashed()
         );
     }
 
+    public function testMapReturnDatabaseCollection()
+    {
+        $this->markTestSkipped();
+
+        $results = [
+            'hits' => [
+                'total' => 2,
+                'hits' => [
+                    [
+                        '_id' => 1,
+                        '_source' => [
+                            'title' => 'foo',
+                        ],
+                    ],
+                    [
+                        '_id' => 2,
+                        '_source' => [
+                            'title' => 'bar',
+                        ],
+                    ],
+                ],
+            ],
+        ];
+
+        $model = $this->mockModel([
+            'key' => 2,
+            'methods' => [
+                'usesSoftDelete',
+                'newQuery',
+                'whereIn',
+                'get',
+                'keyBy',
+            ],
+        ]);
+
+        $model
+            ->method('usesSoftDelete')
+            ->willReturn(false);
+
+        $model
+            ->method('newQuery')
+            ->willReturn($model);
+
+        $model
+            ->method('whereIn')
+            ->willReturn($model);
+
+        $model
+            ->method('get')
+            ->willReturn($model);
+
+        // The mocked `newQuery` chain will return an array of a single model (ID: 2)
+        // When mapping `$results['hits']['hits']`, the first item (ID: 1) will return null in `Collection::map()`
+        // This will result in `Collection::toBase()` being called, converting to a `Support\Collection`
+        $model
+            ->method('keyBy')
+            ->willReturn([
+                2 => $model,
+            ]);
+
+        $builder = $this
+            ->getMockBuilder(FilterBuilder::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $collection = $this->engine->map($builder, $results, $model);
+
+        $this->assertSame(
+            [$model],
+            $collection->all()
+        );
+
+        // Assert that an `Eloquent\Database\Collection` is returned
+        $this->assertInstanceOf(Collection::class, $collection);
+    }
+
     public function testGetTotalCount()
     {
         $results = [