Split independent work off the longest job

Run independent suites in parallel jobs when the overlap saves more than the repeated setup costs.

Prompt

Evaluate and apply this CI technique to my repository: Split independent work off the longest job.

Run independent suites in parallel jobs when the overlap saves more than the repeated setup costs.

Read the technique and its source-backed company examples: https://starsling.dev/ci-playbooks/techniques/split-long-lanes.md

Inspect this repository’s CI workflows, build and test commands, dependencies, and recent run timings. Identify where this technique applies and explain the expected benefit using this repository’s evidence.
Measure a baseline from recent comparable runs: elapsed time, queue time, runner minutes and failures where available. If data is unavailable, say what cannot be measured.
Compare relevant company approaches, checking prerequisites, platform differences and tradeoffs. Rank applicable options by evidence, fit and measurable opportunity; do not present company results as predictions for this repo.
Recommend the smallest safe change, show what checks and fallback paths remain, and ASK ME WHICH CHANGE TO APPROVE BEFORE EDITING ANY FILES.
Only after approval, work on a new feature branch, make one reversible change, and open a reviewable pull request. Never merge or push to a default or protected branch.
Keep required checks, test coverage, deployment and release behavior intact. Validate the change and compare equivalent runs where possible; report limitations and what should be monitored after merge.

View all playbooks

How Stripe used this technique

Read what Stripe changed and follow the original sources.

Split independent work off the longest job

Stripe iOS split installation and integration tests into separate jobs, keeping all five installation variants together so they share setup. Earlier, it moved one measured slow test class into its own job.

The combined job took about 27 minutes; after the split, installation took about 11 to 12 minutes and integration about 13 minutes, running in parallel, in Stripe’s combined CI runs. Source

Use it when: Two independent suites run one after another in the job that holds up the pull request.
Before applying it: Each new job repeats setup and may queue. Keep every test variant and simulator version, and keep one stable required check that reports every job’s result.

How Stripe used this technique

Split independent work off the longest job

Related techniques

Balance test work across shards

Split long test suites across runners

Test supported runtimes concurrently

Company Playbooks

Related guides

Shard tests across parallel jobs

Cut repeated test setup

Diagnose slow tests in CI

Optimize Playwright tests

Make Vitest run mode explicit

Parallelize independent jobs