# `testing.fakeModelFromGlb`

> Contract 2.0.0 · package sha256 `a857eca95b35921109faf997094bb4192f12527d9d0fcd4be7e97f06425bad6e` · generated from `testing.d.ts` by `services/onsite-scripter/scripts/build-contract-docs.mjs`; edit the source, not this file.

Function · `import { fakeModelFromGlb } from '@holostep-configurators/runtime-client/testing';` · labs, `@experimental` · since 2.0.0 · section 24. /testing

A [`FakeModel`](testing.FakeModel.md) read from a GLB with no browser, so a test drives the fake with the product it
ships instead of a hand-written tree: `nodes` in the scene's pre-order walk (a `parent` is its
parent's authored name; a parent whose name another node shares gets an `id`, its authored one
or its part id, `_<n>` when taken, and its children name it by that, so each child stays under
its own parent, as on the runtime), each mesh's `bounds` (its primitives'
POSITION bounds in its own frame), `slot`, `uvChannels` and `doubleSided`, skin joints as
`joint`, `connectors` as `manifestFromGlb` reads them, `clips` with their lengths and animated
nodes, `variants` from the file's KHR_materials_variants, stamped or not (so the fake checks
[`MaterialSpec.variant`](MaterialSpec.variant.md) as the runtime does), and `manifest` only when the GLB is stamped (the
runtime's [`describe(node).manifest`](ModelDescription.manifest.md) is null otherwise). Sync. Errors: throws HoloInputError ('invalid-input', path 'glb') when the
bytes are no glTF 2.0 binary.

## Declaration

```ts
export function fakeModelFromGlb(glb: ArrayBuffer | Uint8Array): FakeModel;
```

## Example

Imports: values (`has`, `validate`, the `Holo*Error` classes, the pure helpers) from `@holostep-configurators/runtime-client`, types from `@holostep-configurators/runtime-client/contract`, `/math` and `/testing` names from those entries; `boot` from the runtime module the root's `loadRuntimeAtFloor` resolves to. A type your page defines is your app's: declare it there, never import it from the package.

Compiled under the contract's strict settings (`examples/declaration/24-fakeModelFromGlb.ts`):

```ts
import { createFakeSession, fakeModelFromGlb } from '@holostep-configurators/runtime-client/testing';
import type { IModelNode, Session } from '@holostep-configurators/runtime-client/contract';
declare const session: Session;
declare const signal: AbortSignal;
declare const glb: Uint8Array;                  // the shipped file's bytes
declare const unit: IModelNode;                 // glbUrl 'unit.glb'
const model = fakeModelFromGlb(glb);
export const meshes = model.nodes.filter((n) => n.mesh).map((n) => n.name); // the file's meshes
export const fake = createFakeSession({ models: { 'unit.glb': model }, root: [unit] });
```

## Generic-API test (spec 3.1)

| Rule | Result |
| --- | --- |
| 1. Neutral name | pass: `fakeModelFromGlb` names no product |
| 2. A precedent | not recorded: no ledger row (coverage.json) names this member or its owner |
| 3. Two apps, or labs | labs (`@experimental` at a stable path, reached through `has()` or `supports()`): it graduates when a second app uses it |
| 4. The cheaper fix first | not recorded per member (Appendix B decides it per need) |