Fetches failed tests for a CircleCI workflow when rerunning said workflow from failed. This is done by using the current commit hash and checking for existing failed tests at said hash. Results are joined by a `,` so they can be easily passed into `xcodebuild -only-testing`. Requires jq

get-failed-tests.sh

  # Set a limit, helps with system outtages and can help avoid passing in a very long list of failed test to xcodebuild which would have the opposite effect
  CCI_FAILED_TESTS_RERUN_LIMIT=11;
  
  # $CIRCLECI_API_TOKEN is a CircleCI API token you presumably set in the project environment variables
  if [[ -n "$CIRCLECI_API_TOKEN" && -n "$CIRCLE_SHA1" && -n "$CIRCLE_WORKFLOW_ID" ]]; then
    pipeline_url="https://circleci.com/api/v2/workflow/$CIRCLE_WORKFLOW_ID"
    echo "🤹🏼‍♂️ Fetching pipeline for $CIRCLE_WORKFLOW_ID"

    pipeline=$(
      curl -H "Circle-Token: $CIRCLECI_API_TOKEN" "$pipeline_url" | jq ' { pipeline_id: .pipeline_id, slug: .project_slug } '
    )
    pipeline_id=$(echo "${pipeline}" | jq ' .pipeline_id ' | tr -d '"')
    slug=$(echo "${pipeline}" | jq ' .slug ' | tr -d '"')

    if [[ -n "$pipeline_id" && -n "$slug" ]]; then
      pipeline_detail_url="https://circleci.com/api/v2/pipeline/$pipeline_id"
      echo "🤹🏼‍♂️ Fetching pipeline $pipeline_id"

      pipeline_hash=$(
        curl -H "Circle-Token: $CIRCLECI_API_TOKEN" "$pipeline_detail_url" | jq ' .vcs.revision ' | tr -d '"'
      )

      if [ "$pipeline_hash" = "$CIRCLE_SHA1" ]; then
        # get the most recent failed workflow in this pipeline
        workflows_url="https://circleci.com/api/v2/pipeline/$pipeline_id/workflow"
        echo "🤹🏼‍♂️ Fetching workflows for pipeline id $pipeline_id"

        failed_workflow_id=$(
          curl -H "Circle-Token: $CIRCLECI_API_TOKEN" "$workflows_url" | jq ' .items | first(.[]  | select(.status == "failed")) | .id ' | tr -d '"'
        )

        if [ -n "$failed_workflow_id" ]; then
          jobs_url="https://circleci.com/api/v2/workflow/$failed_workflow_id/job"
          echo "🤹🏼‍♂️ Fetching job for workflow id $failed_workflow_id"

          job_details=$(
            curl -H "Circle-Token: $CIRCLECI_API_TOKEN" "$jobs_url" | jq ' .items | first(.[]  | select(.name == "'"$CIRCLE_JOB"'")) '
          )

          job_id=$(echo "${job_details}" | jq ' .job_number ' | tr -d '"' )
          job_status=$(echo "${job_details}" | jq ' .status ' | tr -d '"' )

          if [ -n "$job_id" ]; then
            if [ "$job_status" = "failed" ]; then
              tests_url="https://circleci.com/api/v2/project/$slug/$job_id/tests"
              echo "🤹🏼‍♂️ Fetching failed tests for for job id $job_id"

              failed_tests=$(
                curl -H "Circle-Token: $CIRCLECI_API_TOKEN" "$tests_url" | jq ' [.items[]? | select(.result == "failure")] | (.[].classname) |=(split(".") | .[0] |=split("_") |.[0] |=join("-") | join("/")) | map(.classname+"/"+.name) | join(",") '
              )
              if [ -n "$failed_tests" ]; then
                failed_tests_count=$(echo "${failed_tests}" | jq ' split(",") | length ' )
                if (( failed_tests_count < CCI_FAILED_TESTS_RERUN_LIMIT )); then
                  echo "CCI_FAILED_TESTS: $failed_tests"
                  echo CCI_FAILED_TESTS="$failed_tests" >> ${BASH_ENV}
                fi
              else
                echo "🏄🏽‍♂️ Did not find failed tests for commit hash $CIRCLE_SHA1, moving on"
              fi
            fi
          else
            echo "🏄🏽‍♂️ Did not have a job id in $job_details"
          fi
        fi
      fi
    fi
  fi