Provides exact Enzyme → React Testing Library migration patterns for React 18 upgrades. Use this skill whenever Enzyme tests need to be rewritten - shallow, mount, wrapper.find(), wrapper.simulate(), wrapper.prop(), wrapper.state(), wrapper.instance(), Enzyme configure/Adapter calls, or any test file that imports from enzyme. This skill covers the full API mapping and the philosophy shift from implementation testing to behavior testing. Always read this skill before rewriting Enzyme tests - do not translate Enzyme APIs 1:1, that produces brittle RTL tests.
Enzyme has no React 18 adapter and no React 18 support path. All Enzyme tests must be rewritten using React Testing Library.
Enzyme tests implementation. RTL tests behavior.
// Enzyme: tests that the component has the right internal state
expect(wrapper.state('count')).toBe(3);
expect(wrapper.instance().handleClick).toBeDefined();
expect(wrapper.find('Button').prop('disabled')).toBe(true);
// RTL: tests what the user actually sees and can do
expect(screen.getByText('Count: 3')).toBeInTheDocument();
expect(screen.getByRole('button', { name: /submit/i })).toBeDisabled();
This is not a 1:1 translation. Enzyme tests that verify internal state or instance methods don't have RTL equivalents - because RTL intentionally doesn't expose internals. Rewrite the test to assert the visible outcome instead.
For complete before/after code for each Enzyme API, read:
references/enzyme-api-map.mdreferences/async-patterns.md - waitFor, findBy, act(), Apollo MockedProvider, loading states, error states// Every Enzyme test rewrites to this shape:
import { render, screen, fireEvent, waitFor } from '@testing-library/react';
import userEvent from '@testing-library/user-event';
import MyComponent from './MyComponent';
describe('MyComponent', () => {
it('does the thing', async () => {
// 1. Render (replaces shallow/mount)
render(<MyComponent prop="value" />);
// 2. Query (replaces wrapper.find())
const button = screen.getByRole('button', { name: /submit/i });
// 3. Interact (replaces simulate())
await userEvent.setup().click(button);
// 4. Assert on visible output (replaces wrapper.state() / wrapper.prop())
expect(screen.getByText('Submitted!')).toBeInTheDocument();
});
});
getByRole - matches accessible roles (button, textbox, heading, checkbox, etc.)getByLabelText - form fields linked to labelsgetByPlaceholderText - input placeholdersgetByText - visible text contentgetByDisplayValue - current value of input/select/textareagetByAltText - image alt textgetByTitle - title attributegetByTestId - data-testid attribute (last resort)Prefer getByRole over getByTestId. It tests accessibility too.
// Enzyme with context:
const wrapper = mount(
<ApolloProvider client={client}>
<ThemeProvider theme={theme}>
<MyComponent />
</ThemeProvider>
</ApolloProvider>
);
// RTL equivalent (use your project's customRender or wrap inline):
import { render } from '@testing-library/react';
render(
<MockedProvider mocks={mocks} addTypename={false}>
<ThemeProvider theme={theme}>
<MyComponent />
</ThemeProvider>
</MockedProvider>
);
// Or use the project's customRender helper if it wraps providers