module: add two tests for eager imports when using import defer

  - when the defer imported module contains top-level await
  - when the defer imported module is also eagerly imported

Refs: https://github.com/tc39/proposal-defer-import-eval
Signed-off-by: Maya Lekova <maya@igalia.com>
PR-URL: #64197
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

Author: MayaLekova

test/es-module/test-defer-import-eval-with-tla.mjs

@@ -0,0 +1,23 @@
+// Flags: --js-defer-import-eval
+
+// Tests that defer import of a module with top-level await
+// eagerly evaluates the imported module.
+
+import '../common/index.mjs';
+import * as assert from 'assert';
+
+// The importing module will only execute once its dependency containing
+// top-level await has its promises resolved, as per
+// https://github.com/tc39/proposal-top-level-await#what-exactly-is-blocked-by-a-top-level-await
+globalThis.eval_list ||= [];
+
+import defer * as ns from '../fixtures/es-modules/dep-module-top-level-await.mjs';
+
+// Check that the module has already been evaluated.
+assert.strictEqual(globalThis.eval_list.length, 1);
+assert.strictEqual(ns.foo, 42);
+assert.strictEqual(globalThis.eval_list.length, 1);
+assert.partialDeepStrictEqual(['defer-tla-1'], globalThis.eval_list);
+
+// Clean-up
+delete globalThis.eval_list;

test/es-module/test-defer-import-with-regular-import.mjs

@@ -0,0 +1,24 @@
+// Flags: --js-defer-import-eval
+
+// Tests that defer import of a module that is also eagerly imported
+// from another dependency gets executed synchronously, and gets
+// executed exactly once.
+
+import '../common/index.mjs';
+import * as assert from 'assert';
+
+globalThis.eval_list ||= [];
+
+import * as non_deferred from '../fixtures/es-modules/module-with-module-tree.mjs';
+import defer * as deferred from '../fixtures/es-modules/module-deferred-eval.mjs';
+
+// Check that the module has been evaluated exactly once.
+assert.strictEqual(globalThis.eval_list.length, 1);
+assert.strictEqual(deferred.foo, 42);
+assert.partialDeepStrictEqual(['defer-1'], globalThis.eval_list);
+
+// Skip linter warning
+assert.strictEqual(non_deferred.bar, 64);
+
+// Clean-up
+delete globalThis.eval_list;

test/fixtures/es-modules/dep-module-top-level-await.mjs

@@ -0,0 +1,10 @@
+import { setTimeout } from 'node:timers/promises';
+
+if (!globalThis.eval_list) {
+  globalThis.eval_list = [];
+}
+
+export const foo = 42;
+
+await setTimeout(1);
+globalThis.eval_list.push('defer-tla-1');

test/fixtures/es-modules/module-deferred-eval.mjs

@@ -1,8 +1,6 @@
 if (!globalThis.eval_list) {
   globalThis.eval_list = [];
 }
-globalThis.eval_list.push('defer-1');
 
 export const foo = 42;
-
-console.log('executed');
+globalThis.eval_list.push('defer-1');