diff --git a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/tests/ui-core.test.mjs b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/tests/ui-core.test.mjs
new file mode 100644
index 00000000..7ba51456
--- /dev/null
+++ b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/tests/ui-core.test.mjs
@@ -0,0 +1,144 @@
+// SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+import assert from "node:assert/strict";
+import { readFile } from "node:fs/promises";
+import vm from "node:vm";
+
+class ClassList {
+  constructor() { this.values = new Set(); }
+  add(...names) { names.forEach(name => this.values.add(name)); }
+  remove(...names) { names.forEach(name => this.values.delete(name)); }
+  contains(name) { return this.values.has(name); }
+  toggle(name, force) {
+    const enabled = force === undefined ? !this.contains(name) : force;
+    if (enabled) this.add(name); else this.remove(name);
+    return enabled;
+  }
+}
+
+class Element {
+  constructor(tagName, document) {
+    this.tagName = tagName.toUpperCase();
+    this.ownerDocument = document;
+    this.children = [];
+    this.dataset = {};
+    this.attributes = new Map();
+    this.classList = new ClassList();
+    this.listeners = new Map();
+    this.style = {};
+    this.options = [];
+    this.value = "";
+    this.textContent = "";
+  }
+  set id(value) { this._id = value; if (value) this.ownerDocument.elements.set(value, this); }
+  get id() { return this._id || ""; }
+  set className(value) { this.classList = new ClassList(); value.split(/\s+/).filter(Boolean).forEach(name => this.classList.add(name)); }
+  set innerHTML(value) {
+    this._innerHTML = value;
+    if (value.includes('value="confirm"')) {
+      const title = new Element("h2", this.ownerDocument); title.id = "ui-confirm-title";
+      const message = new Element("p", this.ownerDocument); message.id = "ui-confirm-message";
+      const confirm = new Element("button", this.ownerDocument); confirm.value = "confirm";
+      this.append(title, message, confirm);
+      this._confirmButton = confirm;
+    }
+  }
+  get innerHTML() { return this._innerHTML || ""; }
+  appendChild(child) { this.children.push(child); child.parentElement = this; return child; }
+  append(...children) { children.forEach(child => this.appendChild(child)); }
+  insertBefore(child) { return this.appendChild(child); }
+  remove() { if (this.parentElement) this.parentElement.children = this.parentElement.children.filter(child => child !== this); }
+  replaceChildren(...children) { this.children = []; this.options = []; this.append(...children); }
+  setAttribute(name, value) { this.attributes.set(name, String(value)); }
+  getAttribute(name) { return this.attributes.get(name); }
+  addEventListener(type, listener) { this.listeners.set(type, listener); }
+  dispatch(type, event = {}) { this.listeners.get(type)?.({ target: this, preventDefault() {}, ...event }); }
+  querySelector(selector) {
+    if (selector === '[value="confirm"]') return this._confirmButton || null;
+    return null;
+  }
+  querySelectorAll(selector) {
+    if (selector === ".tab[data-tab]") return this.children.filter(child => child.dataset.tab);
+    if (selector === ".sub-tab[data-subtab]") return this.children.filter(child => child.dataset.subtab);
+    if (selector === '[role="tab"]') return this.children.filter(child => child.getAttribute("role") === "tab");
+    return [];
+  }
+  add(option) { this.options.push(option); if (!this.value) this.value = option.value; }
+  showModal() { this.open = true; }
+  close(value) { this.returnValue = value; this.open = false; this.dispatch("close"); }
+  focus() { this.focused = true; }
+  click() { this.clicked = true; }
+}
+
+class DocumentFixture {
+  constructor() {
+    this.readyState = "loading";
+    this.elements = new Map();
+    this.body = new Element("body", this);
+  }
+  createElement(tagName) { return new Element(tagName, this); }
+  getElementById(id) { return this.elements.get(id) || null; }
+  querySelector() { return null; }
+  querySelectorAll() { return []; }
+  addEventListener() {}
+}
+
+const document = new DocumentFixture();
+const storage = new Map();
+const localStorage = {
+  getItem(key) { return storage.has(key) ? storage.get(key) : null; },
+  setItem(key, value) { storage.set(key, String(value)); },
+};
+const window = { document, localStorage, addEventListener() {} };
+const context = vm.createContext({
+  window, document, localStorage,
+  Option: class Option { constructor(label, value) { this.label = label; this.value = value; } },
+  MutationObserver: class MutationObserver { observe() {} },
+  requestAnimationFrame(callback) { callback(); },
+  setTimeout() { return 1; },
+  clearTimeout() {},
+  console,
+});
+
+const source = await readFile(new URL("../ui-core.js", import.meta.url), "utf8");
+new vm.Script(source, { filename: "ui-core.js" }).runInContext(context);
+const ui = window.trxUi;
+
+const toast = ui.notify("Saved", { kind: "success" });
+assert.equal(toast.getAttribute("role"), "status");
+assert.equal(toast.classList.contains("toast-success"), true);
+assert.equal(document.getElementById("toast-region").children.length, 1);
+
+const confirmation = ui.confirm({ title: "Delete?", message: "Permanent", confirmLabel: "Delete" });
+const dialog = document.getElementById("ui-confirm-dialog");
+assert.equal(dialog.open, true);
+assert.equal(document.getElementById("ui-confirm-title").textContent, "Delete?");
+dialog.close("confirm");
+assert.equal(await confirmation, true);
+
+const tabBar = new Element("div", document);
+const firstTab = new Element("button", document); firstTab.dataset.tab = "main"; firstTab.classList.add("active");
+const secondTab = new Element("button", document); secondTab.dataset.tab = "map";
+tabBar.append(firstTab, secondTab);
+const mainPanel = new Element("section", document); mainPanel.id = "tab-main";
+const mapPanel = new Element("section", document); mapPanel.id = "tab-map";
+ui.prepareTabList(tabBar, "primary");
+assert.equal(firstTab.getAttribute("aria-selected"), "true");
+tabBar.dispatch("keydown", { target: firstTab, key: "ArrowRight" });
+assert.equal(secondTab.focused, true);
+assert.equal(secondTab.clicked, true);
+
+localStorage.setItem("trxOperatorLayout:rig-a", "broadcast");
+ui.setActiveRig("rig-a");
+assert.equal(document.body.dataset.operatorLayout, "compact");
+ui.setLayoutCapabilities({ broadcast: true });
+ui.setActiveRig("rig-a");
+assert.equal(document.body.dataset.operatorLayout, "broadcast");
+ui.setActiveRig("rig-b");
+ui.applyLayout("digital");
+assert.equal(document.body.dataset.operatorLayout, "compact");
+assert.equal(localStorage.getItem("trxOperatorLayout:rig-b"), "compact");
+
+console.log("ui-core component tests passed");