Shallow rendering is useful to constrain yourself to testing a component as a unit, and to ensure that your tests aren't indirectly asserting on behavior of child components.
As of Enzyme v3, the shallow API does call React lifecycle methods such as componentDidMount and componentDidUpdate. You can read more about this in the version 3 migration guide.
import { shallow } from 'enzyme';
import sinon from 'sinon';
import Foo from './Foo';
describe('<MyComponent />', () => {
it('renders three <Foo /> components', () => {
const wrapper = shallow(<MyComponent />);
expect(wrapper.find(Foo)).to.have.lengthOf(3);
});
it('renders an `.icon-star`', () => {
const wrapper = shallow(<MyComponent />);
expect(wrapper.find('.icon-star')).to.have.lengthOf(1);
});
it('renders children when passed in', () => {
const wrapper = shallow((
<MyComponent>
<div className="unique" />
</MyComponent>
));
expect(wrapper.contains(<div className="unique" />)).to.equal(true);
});
it('simulates click events', () => {
const onButtonClick = sinon.spy();
const wrapper = shallow(<Foo onButtonClick={onButtonClick} />);
wrapper.find('button').simulate('click');
expect(onButtonClick).to.have.property('callCount', 1);
});
});node(ReactElement): The node to renderoptions(Object[optional]):
options.context: (Object[optional]): Context to be passed into the componentoptions.disableLifecycleMethods: (Boolean[optional]): If set to true,componentDidMountis not called on the component, andcomponentDidUpdateis not called aftersetPropsandsetContext. Default tofalse.options.wrappingComponent: (ComponentType[optional]): A component that will render as a parent of thenode. It can be used to provide context to thenode, among other things. See thegetWrappingComponent()docs for an example. Note:wrappingComponentmust render its children.options.wrappingComponentProps: (Object[optional]): Initial props to pass to thewrappingComponentif it is specified.options.suspenseFallback: (Boolean[optional]): If set to true, when renderingSuspenseenzyme will replace all the lazy components in children withfallbackelement prop. Otherwise it won't handle fallback of lazy component. Default totrue. Note: not supported in React < 16.6.
ShallowWrapper: The wrapper instance around the rendered output.
Find every node in the render tree that matches the provided selector.
Find every node in the render tree that returns true for the provided predicate function.
Remove nodes in the current wrapper that do not match the provided selector.
Remove nodes in the current wrapper that do not return true for the provided predicate function.
Removes nodes that are not host nodes; e.g., this will only return HTML nodes.
Returns whether or not a given node or array of nodes is somewhere in the render tree.
Returns whether or not a given react element exists in the shallow render tree.
Returns whether or not all the given react elements exists in the shallow render tree.
Returns whether or not one of the given react elements exists in the shallow render tree.
Returns whether or not the current render tree is equal to the given node, based on the expected value.
Returns whether or not a given react element matches the shallow render tree.
Returns whether or not the current node has the given class name or not.
Returns whether or not the current node matches a provided selector.
Returns whether or not the current node exists, or, if given a selector, whether that selector has any matching results.
Deprecated: Use .exists() instead.
Returns whether or not the current component returns a falsy value.
Remove nodes in the current wrapper that match the provided selector. (inverse of .filter())
Get a wrapper with all of the children nodes of the current wrapper.
Returns a new wrapper with child at the specified index.
Get a wrapper with all of the parents (ancestors) of the current node.
Get a wrapper with the direct parent of the current node.
Get a wrapper with the first ancestor of the current node to match the provided selector.
Shallow renders the current node and returns a shallow wrapper around it.
Returns a CheerioWrapper of the current node's subtree.
Returns a wrapper of the node rendered by the provided render prop.
A method that un-mounts the component.
Returns a string representation of the text nodes in the current render tree.
Returns a static HTML rendering of the current node.
Returns the node at the provided index of the current wrapper.
Returns the wrapped ReactElement.
Returns the wrapped ReactElements.
Returns a wrapper of the node at the provided index of the current wrapper.
Returns a wrapper of the first node of the current wrapper.
Returns a wrapper of the last node of the current wrapper.
Returns the state of the root component.
Returns the context of the root component.
Returns the props of the current node.
Returns the named prop of the current node.
Returns the key of the current node.
Invokes a prop function on the current node and returns the function's return value.
Simulates an event on the current node.
Manually sets state of the root component.
Manually sets props of the root component.
Manually sets context of the root component.
Returns a wrapper representing the wrappingComponent, if one was passed.
Returns the instance of the root component.
Calls .forceUpdate() on the root component instance.
Returns a string representation of the current shallow render tree for debugging purposes.
Returns the type of the current node of the wrapper.
Returns the name of the current node of the wrapper.
Iterates through each node of the current wrapper and executes the provided function
Maps the current array of nodes to another array.
Reduces the current array of nodes to a value
Reduces the current array of nodes to a value, from right to left.
Returns a new wrapper with a subset of the nodes of the original wrapper, according to the rules of Array#slice.
Taps into the wrapper method chain. Helpful for debugging.
Returns whether or not any of the nodes in the wrapper match the provided selector.
Returns whether or not any of the nodes in the wrapper pass the provided predicate function.
Returns whether or not all of the nodes in the wrapper match the provided selector.
Returns whether or not all of the nodes in the wrapper pass the provided predicate function.
Shallow render the one non-DOM child of the current wrapper, and return a wrapper around the result.