* feat(test): add --clear-data flag to clear app data on launch * test+docs: cover --clear-data flag in CLI parser test and reference * feat(spec): type AttrSelector with known attribute names Replace AttrSelector = Record<string, string> with KnownAttrSelectors plus a string|boolean index signature, so authors get autocomplete and type-checking on testTag / focused / clickable / etc. while raw driver attributes still type-check via the fallback. Boolean state attributes accept native booleans; goja stringifies them at the marshal boundary. AccessibilityElement.attrs becomes RawAttrs (typed string-valued shape of the same canonical names) so element.attrs.testTag autocompletes. * test(verifier): native boolean selector value matches focused=true * docs+folio: use native boolean for focused selector and document typed attrs
@sanderling/spec
TypeScript spec API for sanderling, a property-based UI fuzzer for mobile and web apps.
Spec authors write properties (what the app must always or eventually do), extractors (structured state from the UI), and action generators (what sanderling is allowed to do). The sanderling CLI evaluates the spec in a loop against a running app.
Install
npm install --save-dev @sanderling/spec
Usage
import { extract, always, eventually, actions, weighted, taps, swipes, InputText, Tap } from "@sanderling/spec";
const loggedIn = extract((s) => !!s.ax.find("id:home-tab-bar"));
const balance = extract<number>((s) => (s.snapshots.balance as number) ?? 0);
const emailField = extract((s) => s.ax.find("id:email-field"));
const submitButton = extract((s) => s.ax.find("id:sign-in-button"));
export const properties = {
balanceNeverNegative: always(() => balance.current >= 0),
loginSucceeds: eventually(() => loggedIn.current).within(30, "seconds"),
};
const doLogin = actions(() => {
if (loggedIn.current) return [];
const email = emailField.current;
const submit = submitButton.current;
if (!email || !submit) return [];
return [InputText({ into: email, text: "[email protected]" }), Tap({ on: submit })];
});
export const actionsRoot = weighted(
[50, doLogin],
[10, taps],
[2, swipes],
);
Setup actions
Some action generators are not fuzz targets but preconditions: they drive the
app from a fresh state into the surface you actually want to fuzz (login,
onboarding, permission grants, seed data). Export them as setup instead of
mixing them into actionsRoot. The runner tries setup first; if it yields
no action, it falls through to actionsRoot. State regressing back across the
precondition (e.g. logout under fuzz) automatically re-engages setup.
const login = actions(() => {
if (loggedIn.current) return [];
return [InputText({ into: emailField.current!, text: "[email protected]" }), Tap({ on: submitButton.current! })];
});
export const setup = login;
export const actionsRoot = weighted([60, browse], [40, edit]);
(globalThis as { setup?: unknown }).setup = setup;
Setup is just an ActionGenerator; compose with actions, weighted, or
whenRoute exactly like the main pool.
Works identically across Android, iOS, and web targets.