Add a test to ensure we don't get a performance regression on #hash

1 files changed, 7 insertions, 0 deletions

diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index dc8f25b0e7..541f74f21e 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -1597,4 +1597,11 @@ class BasicsTest < ActiveRecord::TestCase
     assert_equal after_handler, new_handler
     assert_equal orig_handler, klass.connection_handler
   end
+
+  # Note: This is a performance optimization for Array#uniq and Hash#[] with
+  # AR::Base objects. If the future has made this irrelevant, feel free to
+  # delete this.
+  test "records without an id have unique hashes" do
+    assert_not_equal Post.new.hash, Post.new.hash
+  end
 end