fix(tests): Fixed flacky worker test case (#318)

* fix(tests): Fixed flacky worker test case

* refactor: made use of deferred

tests/cases/07_worker.ts

@@ -1,29 +1,17 @@
-import { assert } from "../test.deps.ts";
+import { assertEquals, deferred } from "../test.deps.ts";
 
 export default function workerTests() {
   Deno.test({
     name: "WORKER: Deno does not throw when deno_mongo is imported in worker",
-    fn: async function () {
-      let workerFinished: (p: void | PromiseLike<void>) => void;
-
-      const p = new Promise<void>((resolve, _reject) => {
-        workerFinished = resolve;
-      });
-
+    fn: async () => {
       const importWorker = new Worker(
         new URL("import_worker.ts", import.meta.url).href,
         { type: "module" },
       );
-
-      importWorker.onmessage = (_e) => {
-        workerFinished();
-      };
-
+      const p = deferred<string>();
+      importWorker.onmessage = (e) => p.resolve(e.data);
       importWorker.postMessage("startWorker");
-
-      await p;
-
-      assert(true);
+      assertEquals(await p, "done");
     },
   });
 }

tests/test.deps.ts

@@ -5,3 +5,4 @@ export {
   assertThrows,
 } from "https://deno.land/std@0.117.0/testing/asserts.ts";
 export * as semver from "https://deno.land/x/semver@v1.4.0/mod.ts";
+export { deferred } from "https://deno.land/std/async/mod.ts";