require-vitest-sequence-seed-when-shuffle

Require test.sequence.seed whenever test.sequence.shuffle is enabled.

Rule catalog ID: R035

Targeted pattern scope

vitest.config.*
vitest.workspace.*
vite.config.* when Vitest test.sequence options are used

What this rule reports

This rule reports test.sequence.shuffle: true when no explicit static test.sequence.seed is configured.

Why this rule exists

Shuffled test order can expose order-dependent failures, but reproducing those failures requires a deterministic seed. This rule enforces that reproducibility guardrail.

❌ Incorrect

import { defineConfig } from "vitest/config";

export default defineConfig({
    test: {
        sequence: {
            shuffle: true,
        },
    },
});

✅ Correct

import { defineConfig } from "vitest/config";

export default defineConfig({
    test: {
        sequence: {
            shuffle: true,
            seed: 42,
        },
    },
});

Behavior and migration notes

the rule checks static seed values only
it reports once when shuffle is enabled without a seed

ESLint flat config example

import vite from "@typpi/eslint-plugin-vite";

export default [vite.configs.strict, vite.configs.vitest];

When not to use it

Disable this rule only if you intentionally use non-deterministic shuffled execution in committed config and accept reduced reproducibility.

Package documentation

Vitest config reference

Targeted pattern scope​

What this rule reports​

Why this rule exists​

❌ Incorrect​

✅ Correct​

Behavior and migration notes​

ESLint flat config example​

When not to use it​

Package documentation​

Further reading​