node native test runner

package.json

@@ -9,6 +9,7 @@
     "node": ">=22",
     "yarn": "^1.12.3"
   },
+  "type": "module",
   "dependencies": {
     "@codemirror/autocomplete": "^6.18.3",
     "@codemirror/lang-html": "^6.4.9",
@@ -273,6 +274,7 @@
     "fork-ts-checker-webpack-plugin": "^9.0.2",
     "get-nonce": "^1.0.1",
     "glob": "^7.1.1",
+    "global-jsdom": "^26.0.0",
     "html-webpack-plugin": "5.5.0",
     "http-server": "^14.1.1",
     "husky": "^8.0.2",

test/mocks/css.mjs

@@ -0,0 +1 @@
+export default {};

test/node-loader.mjs

@@ -0,0 +1,25 @@
+import { extname } from "path";
+
+const mock = new URL("mocks/css.mjs", import.meta.url).href;
+
+/**
+ *
+ * This hook intercepts module resolution, allowing us to handle
+ * CSS/SVG files in a custom way. Instead of actually loading the CSS,
+ * we short-circuit the resolution and return a mock module.
+ *
+ * @type {import('node:module').ResolveHook}
+ */
+export async function resolve(specifier, ctx, nextResolve) {
+  const ext = extname(specifier);
+  if (ext === ".css" || ext.startsWith(".svg")) {
+    // For CSS/SCSS, return the mock CSS module and skip default resolution.
+    return {
+      format: "module",
+      url: mock,
+      shortCircuit: true,
+    };
+  }
+
+  return nextResolve(specifier);
+}

test/setup.mjs

@@ -0,0 +1,11 @@
+import { register } from "node:module";
+import { afterEach } from "node:test";
+
+import { cleanup } from "@testing-library/react";
+
+register("./node-loader.mjs", import.meta.url);
+
+afterEach(cleanup);
+
+global.Event = window.Event;
+global.CustomEvent = window.CustomEvent;

yarn.lock

@@ -11514,6 +11514,11 @@ global-dirs@^3.0.0:
   dependencies:
     ini "2.0.0"
 
+global-jsdom@^26.0.0:
+  version "26.0.0"
+  resolved "https://registry.yarnpkg.com/global-jsdom/-/global-jsdom-26.0.0.tgz#fcddd40f81ff11531e5ce87e1a377af016018e98"
+  integrity sha512-BqXpTNZFjP40N+s4k8Bk9HS8GFVPJB/+TKtwcShM84wLv6C5dH9o1dydI3pL6potanhfDiIAVDbaaGj/uSdRSA==
+
 global-modules@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/global-modules/-/global-modules-2.0.0.tgz#997605ad2345f27f51539bea26574421215c7780"