CircleCI rerun failed tests in RSpec with Knapsack Pro Queue Mode. Thanks to that you can rerun only failed tests instead of rerunning the whole CI build. https://docs.knapsackpro.com/ruby/circleci/ & https://knapsackpro.com

.circleci-config.yml

      - run:
          name: Run tests
          command: |
            export CIRCLE_TEST_REPORTS=/tmp/test-results
            mkdir -p $CIRCLE_TEST_REPORTS

            # split slow spec files by test examples
            # https://docs.knapsackpro.com/ruby/split-by-test-examples/
            export KNAPSACK_PRO_RSPEC_SPLIT_BY_TEST_EXAMPLES=true

            # Use circleci CLI to find out if we need to run all tests or rerun failed tests
            # We are telling circleci to split the tests across 1 node to get the full list of all tests for consideration. We leave the splitting to Knapsack Pro.
            export KNAPSACK_PRO_TEST_FILE_LIST_SOURCE_FILE=/tmp/tests_to_run.txt
            circleci tests glob "spec/**/*_spec.rb" | circleci tests run --index 0 --total 1 --command ">$KNAPSACK_PRO_TEST_FILE_LIST_SOURCE_FILE xargs -n1 echo" --verbose
            
            # tell Knapsack Pro to run only tests from the file (and still use Knapsack Pro Queue Mode magic)
            bundle exec rake "knapsack_pro:queue:rspec[--format documentation --format RspecJunitFormatter --out tmp/rspec.xml]"

Ahhhh. Ok, thanks for explaining.