pj
a460eba3db
only role=button was in the tappable set, so link, checkbox, radio, switch, tab, option, the menuitems and treeitem were invisible to the enumeration however plain the control looked. the replay ui builds its step rows as <li role="option">, and the spec dogfooding it had to hand-write an action to reach them because no default verb could see a single row. both producers build the set from the same role list, since the parity test compares them element by element.
@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.