expand on test cases, test in node_modules

test/es-module/test-require-as-esm-interop.mjs

@@ -0,0 +1,53 @@
+// Flags: --experimental-require-module
+import { mustCall } from '../common/index.mjs';
+import assert from 'assert';
+import { directRequireFixture, importFixture } from '../fixtures/pkgexports.mjs';
+
+const tests = {
+  'string': 'cjs',
+  'object': { a: 'cjs a', b: 'cjs b' },
+  'fauxesmdefault': { default: 'faux esm default' },
+  'fauxesmmixed': { default: 'faux esm default', a: 'faux esm a', b: 'faux esm b' },
+  'fauxesmnamed': { a: 'faux esm a', b: 'faux esm b' }
+};
+
+// This test demonstrates interop between CJS and CJS represented as ESM
+// under the new `export const __cjsModule = true` pattern, for the above cases.
+(async () => {
+  for (const [test, exactShape] of Object.entries(tests)) {
+    // Each case represents a CJS dependency, which has the expected shape in CJS:
+    assert.deepStrictEqual(directRequireFixture(`interop-cjsdep-${test}`), exactShape);
+
+    // Each dependency is reexported through CJS as if it is a library being consumed,
+    // which in CJS is fully shape-preserving:
+    assert.deepStrictEqual(directRequireFixture(`interop-cjs/${test}`), exactShape);
+
+    // Now we have ESM conversions of these dependencies, using __cjsModule = true,
+    // staring with the conversion of those dependencies into ESM under require(esm):
+    assert.deepStrictEqual(directRequireFixture(`interop-cjsdep-${test}-esm`), exactShape);
+
+    // When importing these ESM conversions, from require(esm), we should preserve the shape:
+    assert.deepStrictEqual(directRequireFixture(`interop-cjs/${test}-esm`), exactShape);
+
+    // Now if the importer itself is converted into ESM, it should still be able to load the original
+    // CJS and reexport it, preserving the shape:
+    assert.deepStrictEqual(directRequireFixture(`interop-cjs-esm/${test}`), exactShape);
+
+    // And then if we have the converted CJS to ESM importing from converted CJS to ESM,
+    // that should also work:
+    assert.deepStrictEqual(directRequireFixture(`interop-cjs-esm/${test}-esm`), exactShape);
+
+    // Finally, the CJS ESM representation under `import()` should match all these cases equivalently,
+    // where the CJS module is exported as the default export:
+    const esmCjsImport = await importFixture(`interop-cjsdep-${test}`);
+    assert.deepStrictEqual(esmCjsImport.default, exactShape);
+
+    assert.deepStrictEqual((await importFixture(`interop-cjsdep-${test}`)).default, exactShape);
+    assert.deepStrictEqual((await importFixture(`interop-cjs/${test}`)).default, exactShape);
+    assert.deepStrictEqual((await importFixture(`interop-cjsdep-${test}-esm`)).default, exactShape);
+    assert.deepStrictEqual((await importFixture(`interop-cjs/${test}-esm`)).default, exactShape);
+    assert.deepStrictEqual((await importFixture(`interop-cjs-esm/${test}`)).default, exactShape);
+    assert.deepStrictEqual((await importFixture(`interop-cjs-esm/${test}-esm`)).default, exactShape);
+
+  }
+})().then(mustCall());

test/fixtures/pkgexports.mjs

@@ -3,6 +3,10 @@ import { createRequire } from 'module';
 
 const rawRequire = createRequire(fileURLToPath(import.meta.url));
 
+export function directRequireFixture(specifier) {
+  return rawRequire(specifier);
+}
+
 export async function requireFixture(specifier) {
   return { default: rawRequire(specifier ) };
 }