Add comments and assertions to testExistingIndexIsReused

Author: GromNaN

tests/GridFS/BucketFunctionalTest.php

@@ -814,13 +814,22 @@ public function testUploadingFirstFileCreatesIndexes(): void
 
     public function testExistingIndexIsReused(): void
     {
-        // The collections may exist from other tests, ensure they are removed before and after the test
+        // The collections may exist from other tests, ensure they are removed
+        // before and after to avoid potential conflicts.
         $this->dropCollection($this->getDatabaseName(), 'fs.chunks');
         $this->dropCollection($this->getDatabaseName(), 'fs.files');
 
+        // Create indexes with different numeric types before interacting with
+        // GridFS to assert that the library respects the existing indexes and
+        // does not attempt to create its own.
         $this->filesCollection->createIndex(['filename' => 1.0, 'uploadDate' => 1], ['name' => 'test']);
         $this->chunksCollection->createIndex(['files_id' => 1.0, 'n' => 1], ['name' => 'test', 'unique' => true]);
 
+        $this->assertIndexExists('fs.files', 'test');
+        $this->assertIndexExists('fs.chunks', 'test', function (IndexInfo $info): void {
+            $this->assertTrue($info->isUnique());
+        });
+
         $this->bucket->uploadFromStream('filename', self::createStream('foo'));
 
         $this->assertIndexNotExists($this->filesCollection->getCollectionName(), 'filename_1_uploadDate_1');