Use when adding new error messages to React, or seeing "unknown error code" warnings.
npx skills add itechmeat/llm-code --skill "react-testing-library"
Install specific skill from multi-skill repository
# Description
React Testing Library: user-centric component testing with queries, user-event simulation, async utilities, and accessibility-first API.
# SKILL.md
name: react-testing-library
description: "React Testing Library: user-centric component testing with queries, user-event simulation, async utilities, and accessibility-first API."
version: "16.3.2"
release_date: "2026-01-19"
React Testing Library Skill
Quick Navigation
| Topic | Link |
|---|---|
| Queries | references/queries.md |
| User Events | references/user-events.md |
| API | references/api.md |
| Async | references/async.md |
| Debugging | references/debugging.md |
| Config | references/config.md |
Installation
# Core (v16+: @testing-library/dom is peer dependency)
npm install --save-dev @testing-library/react @testing-library/dom
# TypeScript support
npm install --save-dev @types/react @types/react-dom
# Recommended: user-event for interactions
npm install --save-dev @testing-library/user-event
# Recommended: jest-dom for matchers
npm install --save-dev @testing-library/jest-dom
React 19 support: Requires @testing-library/react v16.1.0+
Core Philosophy
"The more your tests resemble the way your software is used, the more confidence they can give you."
Avoid testing:
- Internal state of components
- Internal methods
- Lifecycle methods
- Child component implementation details
Test instead:
- What users see and interact with
- Behavior from user's perspective
- Accessibility (queries by role, label)
Query Priority
Use queries in this order of preference:
1. Accessible to Everyone (Preferred)
// Best β by ARIA role
getByRole("button", { name: /submit/i });
getByRole("textbox", { name: /email/i });
// Form fields β by label
getByLabelText("Email");
// Non-interactive content β by text
getByText("Welcome back!");
2. Semantic Queries
// Images
getByAltText("Company logo");
// Title attribute (less reliable)
getByTitle("Close");
3. Test IDs (Escape Hatch)
// Only when other queries don't work
getByTestId("custom-element");
Query Types
| Type | No Match | 1 Match | >1 Match | Async |
|---|---|---|---|---|
getBy... |
throw | return | throw | No |
queryBy... |
null | return | throw | No |
findBy... |
throw | return | throw | Yes |
getAllBy... |
throw | array | array | No |
queryAllBy... |
[] | array | array | No |
findAllBy... |
throw | array | array | Yes |
When to use:
getBy*β element existsqueryBy*β element may not exist (assertions likeexpect(...).not.toBeInTheDocument())findBy*β element appears asynchronously
Basic Test Pattern
import { render, screen } from "@testing-library/react";
import userEvent from "@testing-library/user-event";
test("shows greeting after login", async () => {
const user = userEvent.setup();
render(<App />);
// Act β simulate user interactions
await user.type(screen.getByLabelText(/username/i), "john");
await user.click(screen.getByRole("button", { name: /login/i }));
// Assert β verify outcome
expect(await screen.findByText(/welcome, john/i)).toBeInTheDocument();
});
User Events
Always use @testing-library/user-event over fireEvent:
import userEvent from "@testing-library/user-event";
test("user interactions", async () => {
const user = userEvent.setup();
// Click
await user.click(element);
await user.dblClick(element);
await user.tripleClick(element);
// Type
await user.type(input, "Hello");
await user.clear(input);
// Select
await user.selectOptions(select, ["option1", "option2"]);
// Keyboard
await user.keyboard("{Enter}");
await user.keyboard("[ShiftLeft>]a[/ShiftLeft]"); // Shift+A
// Clipboard
await user.copy();
await user.paste();
// Pointer
await user.hover(element);
await user.unhover(element);
});
Async Patterns
waitFor β Retry Until Success
await waitFor(() => {
expect(screen.getByText("Loaded")).toBeInTheDocument();
});
// With options
await waitFor(() => expect(callback).toHaveBeenCalled(), {
timeout: 5000,
interval: 100,
});
findBy β Built-in waitFor
// Equivalent to: await waitFor(() => getByText('Loaded'))
const element = await screen.findByText("Loaded");
waitForElementToBeRemoved
await waitForElementToBeRemoved(() => screen.queryByText("Loading..."));
Common Patterns
Custom Render with Providers
// test-utils.tsx
import { render } from "@testing-library/react";
import { ThemeProvider } from "./ThemeProvider";
import { AuthProvider } from "./AuthProvider";
function AllProviders({ children }) {
return (
<ThemeProvider>
<AuthProvider>{children}</AuthProvider>
</ThemeProvider>
);
}
const customRender = (ui, options) => render(ui, { wrapper: AllProviders, ...options });
export * from "@testing-library/react";
export { customRender as render };
Testing Hooks
import { renderHook, act } from "@testing-library/react";
test("useCounter increments", () => {
const { result } = renderHook(() => useCounter());
expect(result.current.count).toBe(0);
act(() => {
result.current.increment();
});
expect(result.current.count).toBe(1);
});
Rerender with New Props
const { rerender } = render(<Counter count={1} />);
expect(screen.getByText("Count: 1")).toBeInTheDocument();
rerender(<Counter count={2} />);
expect(screen.getByText("Count: 2")).toBeInTheDocument();
Query Within Container
import { within } from "@testing-library/react";
const modal = screen.getByRole("dialog");
const submitBtn = within(modal).getByRole("button", { name: /submit/i });
Debugging
// Print entire DOM
screen.debug();
// Print specific element
screen.debug(screen.getByRole("button"));
// Log available roles
import { logRoles } from "@testing-library/react";
logRoles(container);
// With prettyDOM options
screen.debug(undefined, 10000); // max length
jest-dom Matchers
import "@testing-library/jest-dom";
expect(element).toBeInTheDocument();
expect(element).toBeVisible();
expect(element).toBeEnabled();
expect(element).toBeDisabled();
expect(element).toHaveTextContent("Hello");
expect(element).toHaveValue("input value");
expect(element).toHaveAttribute("href", "/home");
expect(element).toHaveClass("active");
expect(element).toHaveFocus();
expect(element).toBeChecked();
Configuration
import { configure } from "@testing-library/react";
configure({
// Custom test ID attribute
testIdAttribute: "data-my-test-id",
// Async timeout
asyncUtilTimeout: 5000,
// Default hidden
defaultHidden: true,
// Throw suggestions (debugging)
throwSuggestions: true,
});
β Prohibitions (Anti-patterns)
// β Don't query by class/id
container.querySelector(".my-class");
// β Don't use container.firstChild
const { container } = render(<Component />);
expect(container.firstChild).toHaveClass("active");
// β Don't use fireEvent when userEvent works
fireEvent.click(button); // Use userEvent.click instead
// β Don't test implementation details
expect(component.state.loading).toBe(false);
// β Don't use waitFor with findBy
await waitFor(() => screen.findByText("x")); // findBy already waits
// β Don't assert inside waitFor callback (unless necessary)
await waitFor(() => {
expect(mockFn).toHaveBeenCalled(); // OK - need to wait for call
});
β Best Practices
// β
Use screen for all queries
import { render, screen } from "@testing-library/react";
render(<Component />);
screen.getByRole("button"); // Good
// β
Prefer userEvent over fireEvent
const user = userEvent.setup();
await user.click(button);
// β
Use findBy for async elements
const element = await screen.findByText("Loaded");
// β
Use queryBy for non-existence assertions
expect(screen.queryByText("Error")).not.toBeInTheDocument();
// β
Use within for scoped queries
const form = screen.getByRole("form");
within(form).getByLabelText("Email");
// β
Use accessible queries (role, label, text)
getByRole("button", { name: /submit/i });
TextMatch Options
// Exact match (default)
getByText("Hello World");
// Substring match
getByText("llo Worl", { exact: false });
// Regex
getByText(/hello world/i);
// Custom function
getByText((content, element) => {
return element.tagName === "SPAN" && content.startsWith("Hello");
});
Quick Reference
| Import | Usage |
|---|---|
render |
Render component to DOM |
screen |
Query the rendered DOM |
cleanup |
Unmount components (auto in Jest) |
act |
Wrap state updates |
renderHook |
Test custom hooks |
within |
Scope queries to element |
waitFor |
Retry until assertion passes |
configure |
Set global options |
userEvent.setup() |
Create user event instance |
# Supported AI Coding Agents
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Learn more about the SKILL.md standard and how to use these skills with your preferred AI coding agent.