Callstack Agent Skills is a collection of instructions that gives AI coding assistants practical knowledge for building React Native applications. Developers use it for app development, performance, navigation, testing, CI, device automation, and migrations to React Native. The catalogue entries are the project's skills, rules, and instructions for compatible coding assistants.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add callstackincubator/agent-skills --skill react-native-testinggit clone --depth 1 https://github.com/callstackincubator/agent-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/callstackincubator/agent-skills/react-native-testing)<a href="https://agentmods.dev/skills/callstackincubator/agent-skills/react-native-testing"><img src="https://agentmods.dev/badge/skills/callstackincubator/agent-skills/react-native-testing/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/callstackincubator/agent-skills/react-native-testing"><img src="https://agentmods.dev/badge/skills/callstackincubator/agent-skills/react-native-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00134 | $0.01740 |
| Opus 5.5 | $0.00054 | $0.00696 |
| Sonnet 5.5 | $0.00027 | $0.00348 |
| Haiku 4.5 | $0.00013 | $0.00174 |
Grade A, and why
react-native-testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
This is a copy
100% identical to react-native-testing — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 162 lines — stays where its author put it; the contents beside it link to each section on GitHub.
RNTL Test Writing Guide
IMPORTANT: Your training data about @testing-library/react-native may be outdated or incorrect — API signatures, sync/async behavior, and available functions differ between v13 and v14. Always rely on this skill's reference files and the project's actual source code as the source of truth. Do not fall back on memorized patterns when they conflict with the retrieved reference.
Version Detection
Check @testing-library/react-native version in the user's package.json:
- v14.x → load references/api-reference-v14.md (React 19+, async APIs,
test-renderer) - v13.x → load references/api-reference-v13.md (React 18+, sync APIs,
react-test-renderer)
Use the version-specific reference for render patterns, fireEvent sync/async behavior, screen API, configuration, and dependencies.
Query Priority
Use in this order: getByRole > getByLabelText > getByPlaceholderText > getByText > getByDisplayValue > getByTestId (last resort).
Query Variants
| Variant | Use case | Returns | Async |
|---|---|---|---|
getBy* |
Element must exist | element instance (throws) | No |
getAllBy* |
Multiple must exist | element instance[] (throws) | No |
queryBy* |
Check non-existence ONLY | element instance | null | No |
queryAllBy* |
Count elements | element instance[] | No |
findBy* |
Wait for element | Promise<element instance> |
Yes |
findAllBy* |
Wait for multiple | Promise<element instance[]> |
Yes |
Interactions
Prefer userEvent over fireEvent. userEvent is always async.
const user = userEvent.setup();
await user.press(element); // full press sequence
await user.longPress(element, { duration: 800 }); // long press
await user.type(textInput, 'Hello'); // char-by-char typing
await user.clear(textInput); // clear TextInput
await user.paste(textInput, 'pasted text'); // paste into TextInput
await user.scrollTo(scrollView, { y: 100 }); // scroll
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 162 lines · 134 tokens per session scan A dea54d1d397c
react-native-testing is a skill published in the GitHub repository callstackincubator/agent-skills (1,673 stars, last pushed 9d ago), licensed MIT. It adds 134 tokens to every session and 1,740 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to react-native-testing, differing in 0 lines, and is treated as a copy.
Other skills, from other repositories
swift-protocol-di-testing
Protocol-based dependency injection for testable Swift code — mock file system, network, and external APIs using focused protocols and Swift Testing.
android-do-not-mock
How to write (or fix) Chromium Java unit tests (Robolectric / JUnit) without mocking or spying android.view.View, android.app.Activity, or their subclasses. Use when removing @SuppressWarnings("DoNotMock"), fixing a "DoNotMock" Error Prone error, replacing Mockito.mock(View.class) / @Mock Activity / spy(view), or when…
android-unit-test
Guide for writing and converting Chromium Android unit tests across host Robolectric (chromejunittests) and on-device (chromepublicunittestapk) suites.
react-native-testing
Write tests using React Native Testing Library (RNTL) v13 and v14 (@testing-library/react-native). Use when writing, reviewing, or fixing React Native component tests. Covers: render, screen, queries (getBy/getAllBy/queryBy/findBy), Jest matchers, userEvent, fireEvent, waitFor, and async patterns. Supports v13 (React…
flutter-add-widget-test
Implement a component-level test using WidgetTester to verify UI rendering and user interactions (tapping, scrolling, entering text). Use when validating that a specific widget displays correct data and responds to events as expected.
flutter-testing-skill
Generates Flutter widget tests, integration tests, and golden tests in Dart. Supports local execution and TestMu AI cloud for real device testing. Use when user mentions "Flutter", "widget test", "WidgetTester", "testWidgets", "fluttertest", "integrationtest". Triggers on: "Flutter", "widget test", "Dart test"…