[aklkv]

Includes the dependency bumps from #82, which is now closed in favour of this PR so review stays in one place.

The problem

The addon's entire mechanism is a classic ember-cli build hook:

preprocessTree(type, tree) {
  if (type === 'test') return new TestTransformFilter(tree, this.addonConfig);
  return tree;
}

That hook does not exist in the Embroider v2 addon format, and never fires in a Vite-built app. On a modern Ember build this addon is already silently inert — installed, resolved, rewritten by @embroider/compat on every build, and transforming nothing. No error, no warning; assertions just quietly stop getting messages.

I confirmed this in a large production monorepo before touching anything: in the Vite-built app, the built bundle contained zero injected messages across 146 eligible message-less assertions. The addon was doing nothing there, and had been for as long as that app has used Vite.

It still works in classically-built packages, which is why this hasn't been widely noticed.

There is no way to fix this while remaining an addon: v2 deliberately removed preprocessTree / treeFor* because host-tree build hooks are broccoli-specific and defeat static analysis. An addon whose only purpose is transforming the consuming app's source has nowhere to stand in v2.

The change

Reimplemented as a Babel plugin, which runs in both pipelines. Note this direction was attempted once before, on the migrate-to-babel-plugin branch back in 2017 — v2 and Vite have since turned it from a nice-to-have into the only way this keeps working.

This lands as v3 — v2.0.0 already shipped in August 2025 (#79, ember 4.12+/node 20+). MIGRATION.md is written as v2 → v3.

Two breaking changes:

1. Installing is no longer enough — the plugin has to be added to the consumer's Babel config. MIGRATION.md leads with this, because the failure mode is silent: nothing errors, the test output just gets worse.
2. Node 22+ is required. Node 20 reached end-of-life on 2026-04-30. Since this is already a major, dropping it here avoids either carrying an unsupported runtime through another cycle or spending a v4 on it. It also collapses engines from ^20.13.0 || >= 22 — a range that existed only because describe from node:test needs 20.13+ — down to >= 22.

// babel.config.mjs (Vite / Embroider)
import qunitNiceErrors from 'ember-qunit-nice-errors';
export default { plugins: [qunitNiceErrors] };

// ember-cli-build.js (classic)
babel: { plugins: [require.resolve('ember-qunit-nice-errors')] }

Config moves from config/environment.js to plugin options, and include/exclude become regular expressions rather than minimatch globs. annotation and persist are gone — both were broccoli concerns.

What this removes

The broccoli pipeline, the dummy app, testem, and the ember-specific lint tooling all go. Dropped dependencies: broccoli-persistent-filter, recast, minimatch, ember-cli-babel, ember-cli-htmlbars, ember-template-imports.

The package now has zero runtime dependencies and a single @babel/core peer.

Dropping the ember-addon keyword also means @embroider/compat no longer rewrites this package on every consumer build.

What this fixes beyond the port

v1 resolves assert by tracking the most recently seen test() call textually and only matching FunctionExpression. This resolves the actual Babel binding:

case	v1	v2
test('x', function (assert) {…})	✅	✅
test('x', async (assert) => {…})	❌ silently skipped	✅
test('x', function (a) { a.ok(…) })	fragile	✅
test.only / test.skip / test.todo	❌	✅

Arrow-function tests are common in .gjs/.gts suites, so this is not a theoretical gap.

It is correspondingly stricter: an assert that is not a test callback's first parameter — one passed to hooks.beforeEach, say — is no longer transformed. v1 would sometimes catch those by accident.

Consumers upgrading should expect assertions that previously had no message to start reporting one. That is the fix working, but it does change CI output.

Verification

• 73 tests (node --test), covering every supported assertion at both arities, already-messaged assertions, unsupported assertions, computed access, spread args, shadowed and unrelated assert bindings, all five test-callback shapes, every test.* variant, nested and inner-test scoping, multi-line assertions and embedded comments, every option including error cases, idempotency, and output-still-parses.
• Verified against @babel/core 8.0.5 and 7.x — the plugin spans both majors with one CJS file and no shims.
• CI runs lint, Node 22/24/26, and a @babel/core 7 job that keeps the lower bound of the peer range honest.

It was also validated end-to-end in a real monorepo across both pipelines — 362 injected messages in the Vite app (previously 0) and 34–133 per classic engine, with 4,570 tests across nine consumers passing, zero failures.

Notes

• Ships as CommonJS deliberately. Babel loads plugin paths with require(), and classic build files are CJS, so a CJS entry works from both an ESM babel.config.mjs and a CJS ember-cli-build.js.
• MIGRATION.md is included in the published tarball.
• There is no longer an Ember version requirement — it works in any QUnit suite compiled with Babel.

[jrjohnson]

@aklkv I'm so happy to have this back in our tests - this made me entire week! THANK YOU!!