Monorepo Vitest setup with shared config and projects

Describe the bug

Hi Vitest team 👋,

I’m working on a fairly large pnpm + Turborepo monorepo and I’d like to get feedback on whether my current Vitest configuration and overall approach are correct, or if I’m misusing some concepts.

---

Context

My monorepo contains multiple workspaces:

• packages/* (CLI, API, shared configs, etc.)

I’m using a shared Vitest config package (@aoc-ts/config-vitest) that is imported by:

• each workspace
• the root of the monorepo

This allows me to:

• run all tests with a single vitest command
• also run them efficiently via Turborepo

---

Shared Vitest configuration

My shared config defines multiple projects (unit + e2e) and shared excludes:

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

const commonExclude = [
  ...configDefaults.exclude,
  '**/__snapshots__/**',
  '**/templates/**',
];

export const sharedConfig = defineConfig({
  server: {
    watch: {
      ignored: commonExclude,
    },
  },
  test: {
    exclude: commonExclude,
    benchmark: {
      exclude: commonExclude,
    },
    projects: [
      {
        extends: true,
        test: {
          name: 'unit',
          testTimeout: 30_000,
          include: ['**/*.unit.test.ts'],
          benchmark: {
            include: ['**/*.unit.bench.ts'],
          },
        },
      },
      {
        extends: true,
        test: {
          name: 'e2e',
          testTimeout: 30_000,
          include: ['**/*.e2e.test.ts'],
          benchmark: {
            include: ['**/*.e2e.bench.ts'],
          },
        },
      },
    ],
  },
});

Each workspace extends this shared config.

---

Root Vitest config (future need)

In the future, I’ll need workspace-specific setupFiles (for mocks, globals, etc.).

From what I understand, the recommended root config for a monorepo should look like this:

import { defineConfig } from 'vitest/config';

export default defineConfig({
  test: {
    projects: ['packages/*'],
  },
});

However, when I introduce this root-level projects config:

• I start seeing unexpected timeouts
• some tests behave differently compared to running Vitest directly inside a workspace
• configuration such as testTimeout does not always seem to be applied as expected

---

Questions

1. Is this overall approach valid?

   • Shared config package
   • test.projects defined inside the shared config
   • Root config delegating to workspaces via projects: ['packages/*']

2. Is it expected that defining projects at the root level can change timeout behavior or test execution semantics?

3. For monorepos that need:

   • shared defaults
   • workspace-specific setupFiles
   • compatibility with Turborepo

   what is the recommended Vitest architecture today?

4. Should:

   • test.projects live only at the root?
   • or only inside workspace configs?
   • or is nesting/combining them discouraged?

---

Goal

My goal is to have:

• one command to run all tests
• predictable timeouts and test behavior
• flexibility to add setupFiles per workspace
• no duplication of config across packages

Any guidance, best practices, or pointers to documentation/examples would be greatly appreciated.

Thanks a lot for your work on Vitest and for your help!

Reproduction

my monorepo : https://gitlab.com/Robin-Ln/aoc-ts

System Info

System:
    OS: macOS 15.5
    CPU: (10) arm64 Apple M1 Pro
    Memory: 89.73 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 25.2.1 - /Users/rlouarn/.nvm/versions/node/v25.2.1/bin/node
    npm: 11.6.2 - /Users/rlouarn/.nvm/versions/node/v25.2.1/bin/npm
    pnpm: 10.27.0 - /Users/rlouarn/Library/pnpm/pnpm
  Browsers:
    Chrome: 143.0.7499.193
    Safari: 18.5
  npmPackages:
    vitest: catalog: => 4.0.16

Used Package Manager

pnpm

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

Start with the shared Vitest configuration, the root projects configuration, and the workspace configs described in the report; reproduce the timeout difference using the linked monorepo. Compare direct workspace runs with root and Turborepo runs, then document the configuration semantics and a supported architecture for shared defaults, workspace setupFiles, and predictable timeouts.