internal: add test for RegisterForSingleUpdate (skyrim-multiplayer#2148)

misc/tests/test_registerforsingleupdate.js

@@ -0,0 +1,34 @@
+const assert = require("node:assert");
+
+const main = async () => {
+  const actorId = mp.createActor(0, [1, 1, 1], 0, 0x3c);
+  const actorObject = { type: 'form', desc: mp.getDescFromId(actorId) };
+
+  const timeWas = Date.now();
+
+  mp.callPapyrusFunction("method", "Form", "RegisterForSingleUpdate", actorObject, [0]);
+  mp.callPapyrusFunction("method", "Form", "RegisterForSingleUpdate", actorObject, [0.1]);
+  mp.callPapyrusFunction("method", "Form", "RegisterForSingleUpdate", actorObject, [0.2]);
+  mp.callPapyrusFunction("method", "Form", "RegisterForSingleUpdate", actorObject, [0.5]);
+
+  let receivedEvents = [];
+
+  mp["onPapyrusEvent:OnUpdate"] = () => {
+    receivedEvents.push(Date.now() - timeWas);
+  };
+
+  await new Promise((resolve) => setTimeout(resolve, 1000));
+
+  // Each call to RegisterForSingleUpdate overrides the previous one for a given form
+  assert.strictEqual(receivedEvents.length, 1);
+  assert(receivedEvents[0] >= 500 && receivedEvents[0] <= 1000);
+};
+
+main().then(() => {
+  console.log("Test passed!");
+  process.exit(0);
+}).catch((err) => {
+  console.log("Test failed!")
+  console.error(err);
+  process.exit(1);
+});