Snapshot tests are a common way to write lightweight component tests. When a snapshot test runs for the first time, it stores its output (e.g. rendered component's HTML structure) in a snapshot output file. Every time the snapshot test runs again, another snapshot output file gets created; which is used to diff the output against the old snapshot…
If you are using Snapshot Tests with Jest for your components, there are a few pitfalls you have to be aware of. Two of them are very likely to apply to your written tests as well: 1) The output of snapshot tests becomes most often too large, if the actual snapshot test renders a component with lots of child components. This holds two problems in…
Jest got introduced by Facebook for testing JavaScript and especially React applications. It's one of the most popular ways to test React components nowadays. Since it comes with its own test runner, you can simply call Jest from the command line to run all your tests. All your tests are defined as test suites (e.g. describe -block) and test…
