describe() declares a test suite. A test suite can contain multiple tests. It accepts two parameters, first is the name of the suite and second is the function containing multiple tests.
it() declares a test. It accepts two parameters, first is the name of the test and second is the function containing code for actual test.
Enzyme allows you to render a single component in isolation, a technique known as “shallow rendering,” and see how changes in the component’s props and state cause the render tree to change.
With shallow rendering, other components in the component’s render tree are treated as black boxes: You can see what props they receive, but not their output.
It let us plug in to the version of React we are using.
npm i --save-dev enzyme enzyme-adapter-react-16