TEST: Add a NS2 test (finally) (#458)

FixJSDOMEnvironment.ts

@@ -0,0 +1,15 @@
+import JSDOMEnvironment from "jest-environment-jsdom";
+
+// https://github.com/facebook/jest/blob/v29.4.3/website/versioned_docs/version-29.4/Configuration.md#testenvironment-string
+export default class FixJSDOMEnvironment extends JSDOMEnvironment {
+  constructor(...args: ConstructorParameters<typeof JSDOMEnvironment>) {
+    super(...args);
+
+    // FIXME https://github.com/nodejs/node/issues/35889
+    // Add missing importActual() function to mirror requireActual(),
+    // which lets us work around the ESM bug.
+    // Wrap the construction of the function in eval, so that transpilers
+    // don't touch the import() call.
+    this.global.importActual = eval("url => import(url)");
+  }
+}

jest.config.js

@@ -1,10 +1,11 @@
 module.exports = {
+  roots: ["<rootDir>/src/", "<rootDir>/test/"],
   moduleFileExtensions: ["ts", "tsx", "js", "jsx"],
   transform: {
     "^.+\\.(js|jsx|ts|tsx)$": "babel-jest",
   },
   testPathIgnorePatterns: [".cypress", "node_modules", "dist"],
-  testEnvironment: "jsdom",
+  testEnvironment: "./FixJSDOMEnvironment.ts",
   moduleNameMapper: {
     "\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$":
       "<rootDir>/test/__mocks__/fileMock.js",

src/NetscriptJSEvaluator.ts

@@ -18,6 +18,22 @@ function makeScriptBlob(code: string): Blob {
   return new Blob([code], { type: "text/javascript" });
 }
 
+// Webpack likes to turn the import into a require, which sort of
+// but not really behaves like import. So we use a "magic comment"
+// to disable that and leave it as a dynamic import.
+//
+// However, we need to be able to replace this implementation in tests. Ideally
+// it would be fine, but Jest causes segfaults when using dynamic import: see
+// https://github.com/nodejs/node/issues/35889 and
+// https://github.com/facebook/jest/issues/11438
+// import() is not a function, so it can't be replaced. We need this separate
+// config object to provide a hook point.
+export const config = {
+  doImport(url: string): Promise<ScriptModule> {
+    return import(/*webpackIgnore:true*/ url);
+  },
+};
+
 export async function compile(script: Script, scripts: Script[]): Promise<ScriptModule> {
   //!shouldCompile ensures that script.module is non-null, hence the "as".
   if (!shouldCompile(script, scripts)) return script.module as Promise<ScriptModule>;
@@ -36,12 +52,7 @@ export async function compile(script: Script, scripts: Script[]): Promise<Script
   script.url = uurls[uurls.length - 1].url;
   // The URL at the top is the one we want to import. It will
   // recursively import all the other modules in the urlStack.
-  //
-  // Webpack likes to turn the import into a require, which sort of
-  // but not really behaves like import. Particularly, it cannot
-  // load fully dynamic content. So we hide the import from webpack
-  // by placing it inside an eval call.
-  script.module = new Promise((resolve) => resolve(eval("import(uurls[uurls.length - 1].url)")));
+  script.module = config.doImport(uurls[uurls.length - 1].url);
   script.dependencies = uurls;
   return script.module;
 }

test/jest/Netscript/RunScript.test.ts

@@ -1,10 +1,25 @@
 import { startWorkerScript } from "../../../src/NetscriptWorker";
+import { config as EvaluatorConfig } from "../../../src/NetscriptJSEvaluator";
 import { Server } from "../../../src/Server/Server";
 import { RunningScript } from "../../../src/Script/RunningScript";
 import { AddToAllServers, DeleteServer } from "../../../src/Server/AllServers";
 import { WorkerScriptStartStopEventEmitter } from "../../../src/Netscript/WorkerScriptStartStopEventEmitter";
 import { AlertEvents } from "../../../src/ui/React/AlertManager";
 
+// Replace Blob/ObjectURL functions, because they don't work natively in Jest
+global.Blob = class extends Blob {
+  code: string;
+  constructor(blobParts?: BlobPart[], options?: BlobPropertyBag) {
+    super();
+    this.code = (blobParts ?? [])[0] + "";
+  }
+};
+global.URL.revokeObjectURL = function () {};
+// Critical: We have to overwrite this, otherwise we get Jest's hooked
+// implementation, which will not work without passing special flags to Node,
+// and tends to crash even if you do.
+EvaluatorConfig.doImport = importActual;
+
 test.each([
   {
     name: "NS1 test /w import",
@@ -30,24 +45,40 @@ test.each([
       },
     ],
   },
-  /*  { // Doesn't work, due to issues with URL.createObjectURL
-    name: "NS2 test, no import",
-    expected: [
-      "false home 8",
-      "Script finished running",
-    ],
+  {
+    name: "NS2 test /w import",
+    expected: ["false home 8", "Script finished running"],
     scripts: [
-      {name: "simple_test.js", code: `
+      {
+        name: "import.js",
+        code: `
+        export function getInfo(ns) {
+          return ns.stock.has4SData();
+        }
+      `,
+      },
+      {
+        name: "simple_test.js",
+        code: `
+        import { getInfo } from "./import.js";
+
         export async function main(ns) {
-          var access = ns.stock.has4SData();
+          var access = getInfo(ns);
           var server = ns.getServer();
           ns.printf("%s %s %d", access, server.hostname, server.maxRam);
         }
-      `},
+      `,
+      },
     ],
-  },*/
+  },
 ])("Netscript execution: $name", async function ({ expected: expectedLog, scripts }) {
-  let server, eventDelete, alertDelete;
+  global.URL.createObjectURL = function (blob) {
+    return "data:text/javascript," + encodeURIComponent(blob.code);
+  };
+
+  let server;
+  let eventDelete = () => {};
+  let alertDelete = () => {};
   try {
     const alerted = new Promise((resolve) => {
       alertDelete = AlertEvents.subscribe((x) => resolve(x));
@@ -75,8 +106,8 @@ test.each([
     expect(result).toBeNull();
     expect(runningScript.logs).toEqual(expectedLog);
   } finally {
-    if (eventDelete) eventDelete();
+    eventDelete();
     if (server) DeleteServer(server.hostname);
-    if (alertDelete) alertDelete();
+    alertDelete();
   }
 });