Locators

A locator names a widget; it does not hold one. Every action and every reader re-resolves from a fresh getTree, so a locator kept across a re-render still points at the right thing, and a ref that went stale between resolve and dispatch is retried rather than thrown.

import { expect, launchApp } from "@nativedesktop/test";

const app = await launchApp({ entry: "examples/counter/main.tsx" });

await app.getByTestId("increment-button").click();
await expect(app.getByTestId("clicks-label")).toContainText("Clicks: 1");

await app.getByRole("textbox").fill("Grocery run");
await app.getByRole("button", { name: "Save" }).click();
await expect(app.getByTestId("toast")).not.toBeVisible();

await app.close();

Attaching to a host somebody else launched (the shape every scripts/*-drive.ts uses, since the acceptance gates own the process) gives the same surface:

import { connectApp, expect } from "@nativedesktop/test";

const app = await connectApp(); // reads ND_AUTOMATION_SOCKET
await expect(app.getByTestId("volume-slider")).toHaveValue("20");

Finding widgets

Factory	Matches on
getByTestId(id)	the node’s testID, exactly
getByRole(role, {name?, exact?, checked?, disabled?})	the schema-declared automation role, plus its accessible name
getByText(text, {exact?})	the node’s own text
getByLabel(text, {exact?})	the accessible name (label, else text, else a string value)
getByPlaceholder(text, {exact?})	the node’s placeholder
locator(selector)	a selector string (below)

A string match is a case-insensitive substring after whitespace normalisation. Pass exact: true, or a RegExp, for anything stricter.

Locators chain, and the chain descends: app.getByTestId("sidebar").getByRole("button") finds buttons inside the sidebar. filter({hasText, has, hasNot}), and(), and first() / last() / nth(i) narrow the current match set without descending.

Selector strings

locator() takes the same parts as a string, joined by >>:

app.locator('role=button[name="Save"] >> nth=1');
app.locator("type=Table >> has-text=Ada >> first");
app.locator("testid=list >> role=button >> last");

Engines: testid=, role=x[name="..."|name=/re/][exact][checked][disabled], text=, label=, placeholder=, type= (the ND widget type, e.g. type=Button). Refinements: nth=i (negative counts from the end), first, last, has-text=, has=(...), has-not=(...), and=(...). A quoted value means an exact match; /re/flags is a regular expression.

Actions and readers

Actions: click, dblclick, rightClick, hover, fill, type, pressSequentially, press, check, uncheck, setChecked, selectOption, focus, blur, scrollIntoViewIfNeeded, dragTo, screenshot.

Readers: boundingBox, textContent, inputValue, getAttribute, isVisible, isEnabled, isChecked, isFocused, count, all, allTextContents, node, ref, and waitFor({state: "attached" | "visible" | "hidden" | "detached"}).

fill replaces a value the way a user finishing an edit would; type appends, matching the type RPC. count() and isVisible() take one tree read and never wait; the other readers wait for the node to exist.

app.keyboard and app.mouse cover what no widget owns: keyboard.press("Meta+A") in Playwright key names, keyboard.type("hello"), mouse.click(x, y) / dblclick / dragTo in logical-window-topleft coordinates. Those ride the input-synthesis RPCs, so they answer -32003 on GTK.

Actionability

Before a single-target action a locator resolves every 100ms until the deadline (app.actionTimeout, 5000ms by default, or a per-call {timeout}), then requires the one match to be:

1. the only match. Two matches is a StrictModeError, thrown at once rather than waited out, because a second element is a selector bug and not a timing one.
2. visible, enabled, and occupying real pixels.
3. still in the same rectangle on the next read, so a widget mid-animation is never clicked.

Readers and screenshot skip the stable-frame wait; they only need the node to exist.

A timeout says what it waited for and what was nearby:

locator.click: Timeout 5000ms exceeded.
Call log:
  - waiting for testid=save-btn
  - resolved 0 elements
Nearest candidates in window "Notes" (3):
  Button  role=button  text="Save As"  testID=save-as  visible enabled  (12,340 88x28)

expect

expect(locator) polls until the matcher passes or the deadline expires; .not inverts the predicate and keeps polling, so .not.toBeVisible() waits for a widget to go away.

toBeVisible, toBeHidden, toBeAttached, toBeEnabled, toBeDisabled, toBeChecked, toBeFocused, toHaveText, toContainText, toHaveValue, toHaveCount, toHaveAttribute.

expect(value) on anything that is not a locator is a plain, non-polling assertion (toBe, toEqual, toContain, toMatch, toBeGreaterThan, and the rest), so a drive script needs only one assertion vocabulary.

What locators do not replace

waitFor and its sugar (app.waitForText, waitForPresent, waitForGone, waitForValue, plus the page predicates urlContains / pageTitleContains / pageTextContains) run host-side on the retained tree at a 50ms tick, with no getTree round trip. Where a script already waits that way, leave it: it is cheaper than any client-side poll, and it is the only path to the page predicates.

Reach past a locator with app.rpc.call(...) when you need a sub-region of a widget (a table row band, a tab strip, a row’s trailing button), a widget-level field the tree models but locators do not (itemCount, a SourceTree’s rows), or a webview RPC. locator.ref() and locator.node() hand you the resolved ref and node for exactly that.

Host methods a locator needs

focus, scrollIntoView, snapshotNode and setWindowFrame are separate RPCs. Against a host that predates one, the call fails with host predates the "<method>" RPC rather than a bare -32601. The optional node fields (checked, label, placeholder, options, selected, expanded) are null on a node the field does not apply to and on a host that predates them, and each reader falls back to text and value there, so a selector behaves the same either way.

app.setWindowSize(w, h) (and app.setWindowFrame({x, y, width, height}) for a move) answers the window’s updated WindowInfo, whose geometry is the same {x, y, w, h} a node carries. locator.screenshot() renders that one node through snapshotNode; pass a path or let the host write beside the automation socket and tell you where.

Acceptance

scripts/locator-drive.ts against examples/locators is the gate for this surface: focus() plus toBeFocused, press("Meta+a"), scrollIntoViewIfNeeded() on a clipped row, a node-sized screenshot(), setWindowSize with the root’s boundingBox() following, isChecked() across check()/uncheck(), and selectOption("Downloads") by label. It prints ND_LOCATOR_OK and runs as the third leg of scripts/mac/mac-gestures.sh.