# Testing Utilities

> Testing Utilities: published entrypoints, signatures, and the constraints around them.

Source: [https://askrjs.com/docs/reference/testing-utilities](https://askrjs.com/docs/reference/testing-utilities)

Status: stable. Packages: @askrjs/askr/testing.

**Published packages are authoritative.** Examples may lag behind a published contract. When guidance differs, verify the exports and TypeScript declarations in your installed package, then file an issue.

## Example

Mock the query or route boundary, drive public state transitions, and inspect invalidation or route warnings without replacing the application runtime.

```tsx
import { createInvalidationRecorder, matchRoute, mockQuery } from '@askrjs/askr/testing';

const projects = mockQuery({ data: [{ id: 'p1', name: 'Northstar' }] });
const invalidations = createInvalidationRecorder();

expect(matchRoute('/projects/p1', { registry })?.params.id).toBe('p1');
expect(invalidations.calls).toEqual([]);
```

## Query mocks

@askrjs/askr/testing exports `mockQuery` (aliased as `queryState`) for constructing a `Query<T>` in any state your components might see: `mockQuery(data)` for fresh data, plus `.loading()`, `.error(err, previousData?)`, `.refreshing(data)`, `.stale(data, reason?)`, and `.pendingWrite(data)`. Each accepts an optional `refresh` callback via `MockQueryOptions` so you can assert refetch behavior without touching a real query registry.

## Invalidation recorder

`createInvalidationRecorder()` returns an `InvalidationRecorder` that captures every cache invalidation call made during a test — each record is `{ prefix, markPendingWrite }`, and the recorder exposes the running list as `calls` and the deduped `prefixes` seen so far. Call `.clear()` between assertions or `.stop()` when you're done listening, so recorders don't leak across test cases.

## Route matching

`matchRoute(path, options)` runs a path through the router's matching logic without booting an app, returning a `RouteMatch` or `null`; pass the same explicit `RouteRegistry` used by your application via `MatchRouteOptions` to test against a specific route set. It's the fastest way to assert that a given URL resolves to the route you expect, including param extraction, before wiring up any actual navigation.

## Warnings

`getRouteWarnings({ registry })` surfaces route-collision problems as `RoutePatternWarning[]` — each warning reports the `kind` (currently `'route-collision'`), the conflicting `path`, the specific `segment` that collides, and an optional `namespace` for MFE-style route grouping. Run it in a test against the same explicit `RouteRegistry` your app uses to catch ambiguous patterns before they show up as a mis-routed request in production.

## Documentation navigation

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