node-test-runner

name	node-test-runner
description	Unit testing patterns for astro-blocks using the built-in Node.js test runner. Covers node:test imports, node:assert/strict assertions, withTempProject temp-dir isolation, env-var save/restore, async test syntax, and subset run commands. Use when writing unit tests, running node --test, using node:test or assert/strict, isolating tests with withTempProject, or running a subset of tests with --test-name-pattern.
license	MIT
metadata	{"authors":"astro-blocks","version":"0.1.0"}

Node.js Test Runner

Overview

This skill covers unit testing in astro-blocks using the built-in node:test runner and node:assert/strict assertion module. All 16 test files under tests/ follow this pattern — no jest, no vitest, no extra frameworks.

Tests import from ../dist/... (the compiled output), so a build step is always required before running. End-to-end browser tests are not in scope here — use the playwright-best-practices skill for those.

---

When to Use

• Writing a new tests/*.test.js file for an API handler, utility, or contract function.
• Debugging a failing or flaky async test.
• Running only one test file or one named test during development.
• Looking up the withTempProject isolation pattern (used in every file that touches data/).
• Looking up env-var save/restore idiom (ASTRO_BLOCKS_PROJECT_ROOT).

---

Running Tests

Full suite

npm test
# expands to: npm run build && node --test tests/*.test.js

Defined in package.json:48. Build is mandatory — tests import from ../dist/.

Single file

node --test tests/configs-handlers.test.js

Subset by name (regex)

node --test --test-name-pattern="CRUD" tests/*.test.js

Watch mode (Node ≥ 22)

node --test --watch tests/cache.test.js

---

Test Structure

Imports

Every test file starts with the same two imports (see tests/cache.test.js:6-7, tests/contract.test.js:1-2):

import test from 'node:test';
import assert from 'node:assert/strict';

Import additional node modules (fs, os, path) as needed. Import the module under test from ../dist/....

Top-level test (flat)

test('getPageCachePath normalizes homepage', () => {
  assert.equal(getPageCachePath({ slug: '/' }), '/');
});

Async test

test('ensureDefaultFiles creates configs.json', async () => {
  await withTempProject(async (tempRoot) => {
    const raw = await fs.readFile(path.join(tempRoot, 'data', 'configs.json'), 'utf-8');
    assert.deepEqual(JSON.parse(raw), { configs: [] });
  });
});

---

Patterns

withTempProject — temp-dir isolation

Every test that reads or writes data/ files must use withTempProject. The helper is defined inline in each test file (not a shared import). Copy this verbatim:

// tests/configs-handlers.test.js:20-38
async function withTempProject(fn) {
  const previousRoot = process.env.ASTRO_BLOCKS_PROJECT_ROOT;
  const tempRoot = await fs.mkdtemp(path.join(os.tmpdir(), 'astro-blocks-<suite>-'));

  process.env.ASTRO_BLOCKS_PROJECT_ROOT = tempRoot;
  await ensureDefaultFiles();

  try {
    await fn(tempRoot);
  } finally {
    if (previousRoot === undefined) {
      delete process.env.ASTRO_BLOCKS_PROJECT_ROOT;
    } else {
      process.env.ASTRO_BLOCKS_PROJECT_ROOT = previousRoot;
    }
    await fs.rm(tempRoot, { recursive: true, force: true });
  }
}

Replace <suite> with a short name matching the test file (e.g. astro-blocks-configs-, astro-blocks-redirects-).

Usage:

test('handlers support CRUD', async () => {
  await withTempProject(async (tempRoot) => {
    // tempRoot is the isolated project root for this test
  });
});

Env-var save/restore (without ensureDefaultFiles)

For simpler tests that only need a custom project root without calling ensureDefaultFiles, use the inline try/finally pattern (see tests/get-config.test.js:15-47):

// tests/get-config.test.js:15-16
const previousRoot = process.env.ASTRO_BLOCKS_PROJECT_ROOT;
const tempRoot = await fs.mkdtemp(path.join(os.tmpdir(), 'astro-blocks-get-config-'));

try {
  process.env.ASTRO_BLOCKS_PROJECT_ROOT = tempRoot;
  // ... test body
} finally {
  if (previousRoot === undefined) delete process.env.ASTRO_BLOCKS_PROJECT_ROOT;
  else process.env.ASTRO_BLOCKS_PROJECT_ROOT = previousRoot;
  await fs.rm(tempRoot, { recursive: true, force: true });
}

Key rule: always check === undefined before deciding whether to delete or restore the env var. Never blindly assign undefined.

node:assert/strict — assertion styles

// Strict equality (===)
assert.equal(response.status, 200);

// Deep structural equality
assert.deepEqual(JSON.parse(raw), { configs: [] });

// Regex match on a string
// tests/contract.test.js:45
assert.match(validateBlocks(schemaMap, [{ type: 'Hero', props: {} }])?.message || '', /campo "Title" es obligatorio/);

// Truthy (array membership, booleans)
assert.ok(tags.includes('astro-blocks'));

// Async rejection — assert a promise rejects
await assert.rejects(
  async () => someAsyncFn(),
  { message: /expected error pattern/ }
);

Importing from dist/

Tests always import from the compiled output, never from src/:

// tests/cache.test.js:9-18
import { CACHE_PATHS, getGlobalCachePaths } from '../dist/utils/cache.js';

// tests/configs-handlers.test.js:12-18
import { ensureDefaultFiles, loadConfigs } from '../dist/api/data.js';
import { handleDeleteConfig, handleGetConfigs } from '../dist/api/handlers.js';

If a new module is added under src/, run npm run build before the test file can import from ../dist/.

---

Compact Rules

• Run the full suite with npm test (builds first); never run node --test without a prior build.
• Import test from node:test and assert from node:assert/strict — no other test frameworks.
• Use withTempProject(fn) for every test that touches data/ files; define it inline per test file.
• Save env vars before mutation (const prev = process.env.X); restore in finally; use delete when prev === undefined.
• Import modules under test from ../dist/..., not ../src/....
• Use assert.equal for scalar equality, assert.deepEqual for objects/arrays, assert.match for regex, assert.rejects for async errors.
• Run a subset with --test-name-pattern=<regex> or a single file with node --test tests/<file>.test.js.