doc (test_runner): shards not supported with watch mode

[pulkit-30]

Affected URL: https://nodejs.org/docs/latest-v20.x/api/test.html#runoptions

It's not mention that we can use shard with watch mode.

Code:

import { tap } from 'node:test/reporters'
import { run } from 'node:test';
import path from 'node:path'

const options = {
  concurrency: 2, // Run 2 test files in parallel
  files: [path.resolve('./index.mjs')], // Specify the test file to run
  setup: (testStream) => {
    console.log("test stream ==>",testStream)
    // Setup listeners before running tests
    testStream.on('test-start', (test) => {
      console.log(`Starting test: ${test.name}`);
    });
  },
  timeout: 5000, // Set a timeout of 5 seconds for test execution
  watch: true, // Enable watch mode
  shard: {
    index: 1, // Index of the shard to run
    total: 2, // Total number of shards
  },
};

run(options)
  .compose(tap)
  .pipe(process.stdout);

error:

node:internal/test_runner/runner:466
      throw new ERR_INVALID_ARG_VALUE('options.shard', watch, 'shards not supported with watch mode');
            ^

TypeError [ERR_INVALID_ARG_VALUE]: The property 'options.shard' shards not supported with watch mode. Received true
    at run (node:internal/test_runner/runner:466:13)
    at file:///Users/pulkitgupta/Desktop/node/index.test.mjs:23:1
    at ModuleJob.run (node:internal/modules/esm/module_job:218:25)
    at async ModuleLoader.import (node:internal/modules/esm/loader:329:24)
    at async loadESM (node:internal/process/esm_loader:28:7)
    at async handleMainPromise (node:internal/modules/run_main:113:12) {
  code: 'ERR_INVALID_ARG_VALUE'
}

Node.js v22.0.0-pre

[nodejs-github-bot]

Review requested:

• @nodejs/test_runner

[benjamingr]

Why would you use sharding (A feature designed to horizontally parallelize test running across machines) with watch mode (a feature designed for development time to iterate on code quickly)?

Not judging, genuinely curious.

[benjamingr]

cc @rluvaton https://github.com/nodejs/node/pull/48639/files#r1251111965

[pulkit-30]

Why would you use sharding (A feature designed to horizontally parallelize test running across machines) with watch mode (a feature designed for development time to iterate on code quickly)?

Not judging, genuinely curious.

Not any particular reason, I was learning about node:test module from node-api docs where I found this missing.

I wasn't expecting any error with the above code, If sharding is not supported with watch mode then it is better to show a warning or log instead and mark watch false internally, and run the test.

Better to not judge me 😅.

[rluvaton]

Should we document why sharding is not supported?

[nodejs-github-bot]

Landed in f9675e1