fix: add io ops to worker to fix fetch (#4054)

2 files changed, 27 insertions, 2 deletions

diff --git a/cli/js/unit_tests.ts b/cli/js/unit_tests.ts
index c43abaa5c..0bdd17964 100644
--- a/cli/js/unit_tests.ts
+++ b/cli/js/unit_tests.ts
@@ -57,10 +57,14 @@ import "./url_search_params_test.ts";
 import "./utime_test.ts";
 import "./write_file_test.ts";
 import "./performance_test.ts";
-import "./permissions_test.ts";
 import "./version_test.ts";
 import "./workers_test.ts";
 
+// FIXME(bartlomieju):
+// This test file revokes permissions, it must be run last,
+// otherwise it might revoke permission for tests that need them.
+import "./permissions_test.ts";
+
 if (import.meta.main) {
   await Deno.runTests();
 }
diff --git a/cli/js/workers_test.ts b/cli/js/workers_test.ts
index 9cb4f4a07..eccf83f65 100644
--- a/cli/js/workers_test.ts
+++ b/cli/js/workers_test.ts
@@ -1,5 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-import { test, assert, assertEquals } from "./test_util.ts";
+import { test, testPerm, assert, assertEquals } from "./test_util.ts";
 
 export interface ResolvableMethods<T> {
   resolve: (value?: T | PromiseLike<T>) => void;
@@ -82,3 +82,24 @@ test(async function workerThrowsWhenExecuting(): Promise<void> {
 
   await promise;
 });
+
+testPerm({ net: true }, async function workerCanUseFetch(): Promise<void> {
+  const promise = createResolvable();
+
+  const fetchingWorker = new Worker("../tests/subdir/fetching_worker.js", {
+    type: "module"
+  });
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  fetchingWorker.onerror = (e: any): void => {
+    e.preventDefault();
+    promise.reject(e.message);
+  };
+
+  fetchingWorker.onmessage = (e): void => {
+    assert(e.data === "Done!");
+    promise.resolve();
+  };
+
+  await promise;
+});