Instead of using toBeTruthy() jest-dom utility library provides the . toBeInTheDocument() matcher, which can be used to assert that an element is in the body of the document, or not. This can be more meaningful than asserting truthfulness in this case.
Using without Jest However, most people using React Testing Library are using it with the Jest testing framework with the testEnvironment set to jest-environment-jsdom (which is the default configuration with Jest 26 and earlier). jsdom is a pure JavaScript implementation of the DOM and browser APIs that runs in Node.
Snapshot testing is a very useful technique to test React component snapshots using the Jest library.
Jest provides a great iteration speed combined with powerful features like mocking modules and timers so you can have more control over how the code executes. React Testing Library is a set of helpers that let you test React components without relying on their implementation details.
From DOM Testing-library Docs - Appearance and Disappearance
Asserting elements are not present
The standard
getBy
methods throw an error when they can't find an element, so if you want to make an assertion that an element is not present in the DOM, you can usequeryBy
APIs instead:const submitButton = screen.queryByText('submit') expect(submitButton).toBeNull() // it doesn't exist
The
queryAll
APIs version return an array of matching nodes. The length of the array can be useful for assertions after elements are added or removed from the DOM.const submitButtons = screen.queryAllByText('submit') expect(submitButtons).toHaveLength(2) // expect 2 elements
not.toBeInTheDocument
The
jest-dom
utility library provides the.toBeInTheDocument()
matcher, which can be used to assert that an element is in the body of the document, or not. This can be more meaningful than asserting a query result isnull
.import '@testing-library/jest-dom/extend-expect' // use `queryBy` to avoid throwing an error with `getBy` const submitButton = screen.queryByText('submit') expect(submitButton).not.toBeInTheDocument()
Use queryBy
/ queryAllBy
.
As you say, getBy*
and getAllBy*
throw an error if nothing is found.
However, the equivalent methods queryBy*
and queryAllBy*
instead return null
or []
:
queryBy
queryBy*
queries return the first matching node for a query, and returnnull
if no elements match. This is useful for asserting an element that is not present. This throws if more than one match is found (use queryAllBy instead).queryAllBy
queryAllBy*
queries return an array of all matching nodes for a query, and return an empty array ([]
) if no elements match.
https://testing-library.com/docs/dom-testing-library/api-queries#queryby
So for the specific two you mentioned, you'd instead use queryByText
and queryByTestId
, but these work for all queries, not just those two.
getBy* throws an error when not finding an elements, so you can check for that
expect(() => getByText('your text')).toThrow('Unable to find an element');
You have to use queryByTestId instead of getByTestId.
Here a code example where i want to test if the component with "car" id isn't existing.
describe('And there is no car', () => {
it('Should not display car mark', () => {
const props = {
...defaultProps,
base: null,
}
const { queryByTestId } = render(
<IntlProvider locale="fr" messages={fr}>
<CarContainer{...props} />
</IntlProvider>,
);
expect(queryByTestId(/car/)).toBeNull();
});
});
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