Ensure ActiveRecord::Base.find_in_batches fires doesnt fire an extra query unless needed

1 files changed, 12 insertions, 0 deletions

diff --git a/activerecord/test/cases/batches_test.rb b/activerecord/test/cases/batches_test.rb
index 705da9f88e..5009a90846 100644
--- a/activerecord/test/cases/batches_test.rb
+++ b/activerecord/test/cases/batches_test.rb
@@ -46,4 +46,16 @@ class EachTest < ActiveRecord::TestCase
       end
     end
   end
+
+  def test_find_in_batches_shouldnt_excute_query_unless_needed
+    post_count = Post.count
+
+    assert_queries(2) do
+      Post.find_in_batches(:batch_size => post_count) {|batch| assert_kind_of Array, batch }
+    end
+
+    assert_queries(1) do
+      Post.find_in_batches(:batch_size => post_count + 1) {|batch| assert_kind_of Array, batch }
+    end
+  end
 end
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