diff --git a/lib/chewy/minitest/helpers.rb b/lib/chewy/minitest/helpers.rb
index 26ff95e3f..e9fbd1362 100644
--- a/lib/chewy/minitest/helpers.rb
+++ b/lib/chewy/minitest/helpers.rb
@@ -97,7 +97,7 @@ def mock_elasticsearch_response_sources(index, hits, &block)
               {
                 '_index' => index.index_name,
                 '_type' => '_doc',
-                '_id' => (i + 1).to_s,
+                '_id' => hit[:id] || (i + 1).to_s,
                 '_score' => 3.14,
                 '_source' => hit
               }