Add support for groupBy

src/FakeDB.php

@@ -442,13 +442,21 @@ public static function filter($query, $columns = ['*']): Collection
     {
         $orderBy = $query->orders;
         $selects = $query->columns;
+        $groups = $query->groups;
         $offset = $query->offset;
         $limit = $query->limit;
         $from = $query->from;
         $joins = $query->joins ?? [];
         $base = FakeDB::$fakeRows[$from] ?? [];
         $collection = FakeDB::performJoins($base, $joins);
 
+        if ($groups) {
+            foreach ($groups as &$group) {
+                $group = $from.'.'.$group;
+            }
+            $collection = $collection->groupBy($groups);
+        }
+
         foreach ($orderBy ?: [] as $i => $_order) {
             if (isset($_order['column'])) {
                 $orderBy[$i]['column'] = FakeDB::prefixColumn($_order['column'], $from, $joins);

tests/GroupByTest.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace Imanghafoori\EloquentMockery\Tests;
+
+use Illuminate\Database\Eloquent\Model;
+use Imanghafoori\EloquentMockery\FakeDB;
+use PHPUnit\Framework\TestCase;
+
+class GroupByModel extends Model
+{
+    protected $table = 'my_tbl';
+}
+
+class GroupByTest extends TestCase
+{
+    public function setUp(): void
+    {
+        FakeDB::mockQueryBuilder();
+    }
+
+    public function tearDown(): void
+    {
+        FakeDB::dontMockQueryBuilder();
+    }
+
+    /**
+     * @test
+     */
+    public function groupByBasicTest()
+    {
+        FakeDB::addRow('my_tbl', ['id' => 1,'col1' => 'v1']);
+        FakeDB::addRow('my_tbl', ['id' => 2,'col1' => 'v2']);
+        FakeDB::addRow('my_tbl', ['id' => 3,'col1' => 'v1']);
+        FakeDB::addRow('my_tbl', ['id' => 4,'col1' => 'v3']);
+        FakeDB::addRow('my_tbl', ['id' => 5,'col1' => 'v2']);
+
+        $rows = GroupByModel::query()->groupBy('col1')->get();
+
+        $this->assertCount(3, $rows);
+
+        $this->assertEquals(3, $rows[0]->id);
+        $this->assertEquals(5, $rows[1]->id);
+        $this->assertEquals(4, $rows[2]->id);
+    }
+}