From af6b72aafd4d57461eb0e22aa93425c11e84fc0d Mon Sep 17 00:00:00 2001
From: MayaLekova <maya@igalia.com>
Date: Mon, 29 Jun 2026 16:55:44 +0300
Subject: [PATCH] module: add tests for two cases of eager imports:

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

Refs: https://github.com/tc39/proposal-defer-import-eval
Signed-off-by: Maya Lekova <maya@igalia.com>
---
 .../test-defer-import-eval-with-tla.mjs       | 24 +++++++++++++++++++
 .../test-defer-import-with-regular-import.mjs | 23 ++++++++++++++++++
 .../es-modules/dep-module-top-level-await.mjs | 11 +++++++++
 3 files changed, 58 insertions(+)
 create mode 100644 test/es-module/test-defer-import-eval-with-tla.mjs
 create mode 100644 test/es-module/test-defer-import-with-regular-import.mjs
 create mode 100644 test/fixtures/es-modules/dep-module-top-level-await.mjs

diff --git a/test/es-module/test-defer-import-eval-with-tla.mjs b/test/es-module/test-defer-import-eval-with-tla.mjs
new file mode 100644
index 00000000000000..db546ccbb092ec
--- /dev/null
+++ b/test/es-module/test-defer-import-eval-with-tla.mjs
@@ -0,0 +1,24 @@
+// 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
+if (!globalThis.eval_list) {
+  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.partialDeepStrictEqual(['defer-tla-1'], globalThis.eval_list);
+
+// Clean-up
+delete globalThis.eval_list;
diff --git a/test/es-module/test-defer-import-with-regular-import.mjs b/test/es-module/test-defer-import-with-regular-import.mjs
new file mode 100644
index 00000000000000..6d3f765ae3008c
--- /dev/null
+++ b/test/es-module/test-defer-import-with-regular-import.mjs
@@ -0,0 +1,23 @@
+// 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';
+
+if (!globalThis.eval_list) {
+  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);
+
+// Clean-up
+delete globalThis.eval_list;
diff --git a/test/fixtures/es-modules/dep-module-top-level-await.mjs b/test/fixtures/es-modules/dep-module-top-level-await.mjs
new file mode 100644
index 00000000000000..4ef3c827350fca
--- /dev/null
+++ b/test/fixtures/es-modules/dep-module-top-level-await.mjs
@@ -0,0 +1,11 @@
+import { setTimeout } from 'node:timers/promises';
+
+if (!globalThis.eval_list) {
+  globalThis.eval_list = [];
+}
+globalThis.eval_list.push('defer-tla-1');
+
+export const foo = 42;
+
+await setTimeout(1);
+console.log('executed');