I am writing test and below is my test case. When I run test I get below error. What is wrong with that and how can I fix this? Answer From the doc: The jest object is automatically in scope within every test file. The methods in the jest object help create mocks and let you control Jest’s overall behavior.
Tag: enzyme
Jest tests keep failing for React component that renders various HTML elements based on type by using switch statement
I have a React Component that takes an array and iterates over each node, styling and rendering HTML elements based on the types found within the array. I have everything running properly and now I’m trying to write a test using Jest to check that: The component doesn’t render anything when it receives an empty array The component renders the
SyntaxError: Unexpected token ‘<' on shallow render with Enzyme and Jest in React
I am running tests with jest and enzyme in my React application, and while my simple sanity check test (2+2 expect 4) works, this error is thrown when I go to shallow render a component. It also throws when I try to replace shallow() with render() Here is the app.test.js file: babel.config.js: EDIT : I added babel-jest and now this
Unit test with react hook fails
I don’t understand the result I get on this unit test. I expect the second check for textField.valid to be true and instead it returns false. Below is part of the component I’m testing against: … Below is the test I’m running: The output of console.log(wrapper.debug()) is the following: So why does the test fail? Answer The problem was that
How to mock/spy useState hook in jest?
I am trying to spy on useState React hook but i always get the test failed This is my React component: counter.test.js: Unfortunately this doesn’t work and i get the test failed with that message: Answer You need to use React.useState instead of the single import useState. I think is about how the code gets transpiled, as you can see
How to mock the useState hook implementation so that it actually changes the state during testing
I’m trying to test a component which renders two different sub-components when its internal state changes from false to true: when it’s false it renders a button that, if pressed, changes the state from false to true and renders the other one. The other is a form that on submit does the opposite. I’ve tried to spy on the useState
TypeError: ShallowWrapper::renderProp() can only be called on custom components
I am trying to test the render props of my React component, and have followed some advice in doing so, however it is not working. Component: And my test: But I get this error message: ● › Renders a form I have not found anything online about the error message title: TypeError: ShallowWrapper::renderProp() can only be called on custom components
Testing debounced function in React component with Jest and Enzyme
I am testing a React component using Jest and Enzyme, and am having difficulty testing that a debounced function is called properly (or at all). I’ve simplified the component code below (edited to make code even simpler), link to codepen here I figured that the debounced function test should be pretty similar to one that is non-debounced, but with a
eslint should be listed in the project’s dependencies, not devDependencies
Either I don’t understand dependencies vs. devDependencies in node 100% yet or eslint is just wrong here (not capable of analyzing this correctly): These are test dependencies, so why is it saying that they should be listed in dependencies? Additional note: We’re using Travis as our CI so I don’t know if it makes a difference for that at all
Components using Date objects produce different snapshots in different timezones
I’m using Enzyme with enzyme-to-json to do Jest snapshot testing of my React components. I’m testing shallow snapshots of a DateRange component that renders a display field with the current range (e.g. 5/20/2016 – 7/18/2016) and two DateInput components that allow selecting a Date value. This means that my snapshot contains the Dates I pass to the component both in