Testing in React Native — Jest & Detox – Pillow.codes

Testing in React Native  with  Jest & Detox



#ReactJS #Jest

  • Testing can help identify bugs introduced during the development phase of the app and addressing these bugs before release means that your users will always get to use a reliable product.What kind of tests can we use?Unit tests are used to test small modular pieces of code (aka units) independently.Integration tests…
  • One of my favorite things about Jest is a feature called Snapshot testing.Snapshot tests are a very useful tool whenever you want to make sure the UI for a component or the object from an redux action or reducer does not change unexpectedly.Here’s a good explanation of what a snapshot…
  • Here’s a simple example on how to set this up.Jest tests for Pillow Pro appE2E tests: DetoxAn end-to-end test emulates a user by finding and interacting with pieces of UI in your app in a production/release environment.Detox is a gray box E2E Tests and Automation Library for Mobile Apps built by WixWe…
  • Here’s how we handle them in Detox:LoginHere’s a simple example of what a detox test for logging into the app might look like:DemoAnd finally, here’s a part of our E2E test suite in action.
  • Also, automating the tests on Bitrise CI has helped us streamline our release pipeline by preceding every release with the tests workflow.Hopefully, this post details how easy it is to test a React Native app and automate the testing process as well.

At Pillow, we release an update to our Pillow Pro app (iOS & Android) every 2 weeks or so. Most releases are over-the-air (OTA) updates that are done using CodePush, and are fully automated with…
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Jest 15.0: New Defaults for Jest · Jest

@marekpiechut Mind updating this part? Jest does *not* mock by default anymore.

  • It can now switch between running all tests or only test files related to changed files by pressing a or o .
  • Jest now uses verbose mode when only a single test file is executed.
  • By pressing p a prompt appears that allows to specify a test pattern to focus on a specific set of files.
  • Jest used to implicitly reset all modules before each test and we recommended requiring modules in beforeEach or inside of tests.
  • When running multiple tests in parallel, it was often hard to find out which test and which module was calling a log function.

We spent the past year making Jest faster, easier to configure, added tons of features and built snapshot testing. However, there were two areas where we invested very little: the CLI output and user experience. With Jest 15 we are changing the framework radically to make it easier to use both for beginners and experienced users. We are excited that our investment in Jest is now paying off: we can move fast and improve the framework for Facebook and the open source community at light-speed. Jest’s goal is to come with batteries included and to require as little configuration as necessary. We recently got a chance to explain our philosophy on a create-react-app issue.
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