react.dev/docs/10.4-test-utils.md

---
id: test-utils
title: Test Utilities
permalink: test-utils.html
prev: two-way-binding-helpers.html
next: clone-with-props.html
---

`React.addons.TestUtils` makes it easy to test React components in the testing framework of your choice (we use [Jest](https://facebook.github.io/jest/)).

### Simulate

```javascript
Simulate.{eventName}(DOMElement element, object eventData)
```

Simulate an event dispatch on a DOM node with optional `eventData` event data. **This is possibly the single most useful utility in `ReactTestUtils`.**

Example usage:

```javascript
var node = React.findDOMNode(this.refs.input);
React.addons.TestUtils.Simulate.click(node);
React.addons.TestUtils.Simulate.change(node, {target: {value: 'Hello, world'}});
React.addons.TestUtils.Simulate.keyDown(node, {key: "Enter"});
```

`Simulate` has a method for every event that React understands.

### renderIntoDocument

```javascript
ReactComponent renderIntoDocument(ReactElement instance)
```

Render a component into a detached DOM node in the document. **This function requires a DOM.**

### mockComponent

```javascript
object mockComponent(function componentClass, string? mockTagName)
```

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.

### isElement

```javascript
boolean isElement(ReactElement element)
```

Returns true if `element` is any ReactElement.

### isElementOfType

```javascript
boolean isElementOfType(ReactElement element, function componentClass)
```

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

### isDOMComponent

```javascript
boolean isDOMComponent(ReactComponent instance)
```

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

### isCompositeComponent

```javascript
boolean isCompositeComponent(ReactComponent instance)`
```

Returns true if `instance` is a composite component (created with `React.createClass()`)

### isCompositeComponentWithType

```javascript
boolean isCompositeComponentWithType(ReactComponent instance, function componentClass)
```

Returns true if `instance` is a composite component (created with `React.createClass()`) whose type is of a React `componentClass`.

### findAllInRenderedTree

```javascript
array findAllInRenderedTree(ReactComponent tree, function test)
```

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

```javascript
array scryRenderedDOMComponentsWithClass(ReactComponent tree, string className)
```

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

### findRenderedDOMComponentWithClass

```javascript
ReactComponent findRenderedDOMComponentWithClass(ReactComponent tree, string className)
```

Like `scryRenderedDOMComponentsWithClass()` 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

```javascript
array scryRenderedDOMComponentsWithTag(ReactComponent tree, string tagName)
```

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

### findRenderedDOMComponentWithTag

```javascript
ReactComponent findRenderedDOMComponentWithTag(ReactComponent tree, string tagName)
```

Like `scryRenderedDOMComponentsWithTag()` 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

```javascript
array scryRenderedComponentsWithType(ReactComponent tree, function componentClass)
```

Finds all instances of components with type equal to `componentClass`.

### findRenderedComponentWithType

```javascript
ReactComponent findRenderedComponentWithType(ReactComponent tree, function componentClass)
```

Same as `scryRenderedComponentsWithType()` 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.


## Shallow rendering

Shallow rendering is an experimental feature that lets you render a component "one level deep" and assert facts about what its render method returns, without worrying about the behavior of child components, which are not instantiated or rendered. This does not require a DOM.

```javascript
ReactShallowRenderer createRenderer()
```

Call this in your tests to create a shallow renderer. You can think of this as a "place" to render the component you're testing, where it can respond to events and update itself.

```javascript
shallowRenderer.render(ReactElement element)
```

Similar to `React.render`.

```javascript
ReactComponent shallowRenderer.getRenderOutput()
```

After render has been called, returns shallowly rendered output. You can then begin to assert facts about the output. For example, if your component's render method returns:

```javascript
<div>
  <span className="heading">Title</span>
  <Subcomponent foo="bar" />
</div>
```

Then you can assert:

```javascript
result = renderer.getRenderOutput();
expect(result.type).toBe('div');
expect(result.props.children).toEqual([
  <span className="heading">Title</span>,
  <Subcomponent foo="bar" />
]);
```

Shallow testing currently has some limitations, namely not supporting refs. We're releasing this feature early and would appreciate the React community's feedback on how it should evolve.