vercel__workflow/vitest.config.ts

import { configDefaults, defineConfig } from 'vitest/config';

export default defineConfig({
  test: {
    testTimeout: 60_000,
    // The e2e suites drive real deployments, so individual tests can lose
    // timing races (queue delays, cold starts, watcher latency) that a
    // second attempt absorbs. One CI retry keeps a single racy test from
    // failing a 20+ minute matrix job; retried tests stay visible — the
    // github-reporter annotates them and the PR comment lists them — so
    // real races still get looked at. Harnesses where a failure is itself
    // the signal (event-log-race-repro, benchmarks) pin `retry: 0` locally.
    // Local runs keep retry at 0 so races reproduce while debugging.
    retry: process.env.CI ? 1 : 0,
    // How many concurrent tests vitest runs from a `describe.concurrent`
    // suite (vitest's own default is 5). Only the e2e conformance suite is
    // concurrent, so this is effectively its dial. Tunable because the right
    // value is a property of the runner and the deployment rather than of
    // the tests: every CLI assertion spawns a `node` child, and a CI runner
    // has few cores, so too high a value inflates per-test latency until
    // tests exceed budgets written for an unloaded suite. Each lane logs
    // what it observed (see `summarizeLoad` in the e2e utils).
    maxConcurrency: Number(process.env.WORKFLOW_E2E_MAX_CONCURRENCY ?? 5),
    // Positional file arguments are regex filters, not paths, so
    // `vitest run packages/core/e2e/x.test.ts` also matches
    // `.claude/worktrees/<name>/packages/core/e2e/x.test.ts` when agent
    // worktrees live inside the repo (see .gitignore). Those copies belong to
    // other branches: they would run their own version of the suite against the
    // same backend and overwrite the same result files.
    exclude: [...configDefaults.exclude, '**/.claude/**'],
  },
});