Test Utilities

Importing

Overview

ReactTestUtils makes it easy to test React components in the testing framework of your choice. At Facebook we use Jest for painless JavaScript testing. Learn how to get started with Jest through the Jest website's React Tutorial.

Note:

We recommend using which is designed to enable and encourage writing tests that use your components as the end users do.

For React versions <= 16, the library makes it easy to assert, manipulate, and traverse your React Components' output.

Reference

act()

To prepare a component for assertions, wrap the code rendering it and performing updates inside an act() call. This makes your test run closer to how React works in the browser.

Note

If you use react-test-renderer, it also provides an act export that behaves the same way.

For example, let's say we have this Counter component:

Here is how we can test it:

• Don't forget that dispatching DOM events only works when the DOM container is added to the document. You can use a library like to reduce the boilerplate code.

• The recipes document contains more details on how act() behaves, with examples and usage.

mockComponent()

Pass a mocked component module to this method to augment it with useful methods that allow it to be used as a dummy React component. Instead of rendering as usual, the component will become a simple <div> (or other tag if mockTagName is provided) containing any provided children.

Note:

mockComponent() is a legacy API. We recommend using instead.

isElement()

Returns true if element is any React element.

isElementOfType()

Returns true if element is a React element whose type is of a React componentClass.

isDOMComponent()

Returns true if instance is a DOM component (such as a <div> or <span>).

isCompositeComponent()

Returns true if instance is a user-defined component, such as a class or a function.

isCompositeComponentWithType()

Returns true if instance is a component whose type is of a React componentClass.

findAllInRenderedTree()

Traverse all components in tree and accumulate all components where test(component) is true. This is not that useful on its own, but it's used as a primitive for other test utils.

scryRenderedDOMComponentsWithClass()

Finds all DOM elements of components in the rendered tree that are DOM components with the class name matching className.

findRenderedDOMComponentWithClass()

Like but expects there to be one result, and returns that one result, or throws exception if there is any other number of matches besides one.

scryRenderedDOMComponentsWithTag()

Finds all DOM elements of components in the rendered tree that are DOM components with the tag name matching tagName.

findRenderedDOMComponentWithTag()

Like but expects there to be one result, and returns that one result, or throws exception if there is any other number of matches besides one.

scryRenderedComponentsWithType()

Finds all instances of components with type equal to componentClass.

findRenderedComponentWithType()

Same as but expects there to be one result and returns that one result, or throws exception if there is any other number of matches besides one.

renderIntoDocument()

Render a React element into a detached DOM node in the document. This function requires a DOM. It is effectively equivalent to:

Note:

You will need to have window, window.document and window.document.createElement globally available before you import React. Otherwise React will think it can't access the DOM and methods like setState won't work.

Other Utilities

Simulate

Simulate an event dispatch on a DOM node with optional eventData event data.

Simulate has a method for every event that React understands.

Clicking an element

Changing the value of an input field and then pressing ENTER.

Note

You will have to provide any event property that you're using in your component (e.g. keyCode, which, etc...) as React is not creating any of these for you.