chore: enforce scoped formatting and browser package boundaries

src/tooling/packageBoundaries.test.mjs

@@ -0,0 +1,77 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { mkdtemp, mkdir, writeFile, rm } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import path from 'node:path';
+import { checkPackageBoundaries } from '../../scripts/check-package-boundaries.mjs';
+
+async function fixture(
+  t,
+  entry = 'export const value = 1;',
+  extraExports = {},
+) {
+  const root = await mkdtemp(path.join(tmpdir(), 'gev-boundaries-'));
+  t.after(() => rm(root, { recursive: true, force: true }));
+  await mkdir(path.join(root, 'scripts'));
+  await writeFile(
+    path.join(root, 'package.json'),
+    JSON.stringify({
+      name: 'boundary-fixture',
+      type: 'module',
+      exports: { './feature': './entry.js', ...extraExports },
+    }),
+  );
+  await writeFile(
+    path.join(root, 'scripts/package-boundaries.json'),
+    JSON.stringify({
+      feature: { exports: ['./feature'], modules: ['entry.js'], external: [] },
+    }),
+  );
+  await writeFile(path.join(root, 'entry.js'), entry);
+  return root;
+}
+
+test('a declared browser export builds without running app setup', async (t) => {
+  const root = await fixture(t);
+  await writeFile(
+    path.join(root, 'vite.config.js'),
+    "throw new Error('must not load app config');",
+  );
+  assert.deepEqual(await checkPackageBoundaries(root), [
+    { name: 'feature', exports: 1, modules: 1 },
+  ]);
+});
+
+test('an unclassified package export fails the boundary gate', async (t) => {
+  const root = await fixture(t, undefined, { './another': './another.js' });
+  await assert.rejects(
+    checkPackageBoundaries(root),
+    /exactly one boundary group/,
+  );
+});
+
+test('even an unused import of application code violates ownership', async (t) => {
+  const root = await fixture(
+    t,
+    "import { app } from './startup.js'; export const value = 1;",
+  );
+  await writeFile(path.join(root, 'startup.js'), 'export const app = 2;');
+  await assert.rejects(checkPackageBoundaries(root), /unowned module.*startup/);
+});
+
+test('Node builtins cannot enter a browser export', async (t) => {
+  const root = await fixture(
+    t,
+    "import fs from 'node:fs'; export const value = fs;",
+  );
+  await assert.rejects(checkPackageBoundaries(root), /unowned module|browser/);
+});
+
+test('dynamic imports obey the same component ownership rule', async (t) => {
+  const root = await fixture(
+    t,
+    "export const load = () => import('./startup.js');",
+  );
+  await writeFile(path.join(root, 'startup.js'), 'export const app = 2;');
+  await assert.rejects(checkPackageBoundaries(root), /unowned module.*startup/);
+});