sanderling/pkg/spec

@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, now, 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);

export const properties = {
  balanceNeverNegative: always(() => balance.current >= 0),
  loginSucceeds: eventually(() => loggedIn.current).within(30, "seconds"),
};

const doLogin = actions(() => {
  if (loggedIn.current) return [];
  const email = state.ax.find("id:email-field");
  const submit = state.ax.find("id:sign-in-button");
  if (!email || !submit) return [];
  return [InputText({ into: email, text: "[email protected]" }), Tap({ on: submit })];
});

export const actions = weighted(
  [50, doLogin],
  [10, taps],
  [2,  swipes],
);

Works identically across Android, iOS, and web targets.