Standalone Jest `.test` files in /app directory with expo-router cause bundling error about expo HOT 3 CLOSED

This is a feature we will explore in the future but as @amandeepmittal stated, for now you'll need to perform the second approach.

Testing with React Native isn't as simple as a single .test file, as due to the multi-platform nature of Expo Router you'll most likely have multiple .test.ios/.test.android/.test.web files. Is having a 1:3 route:test file ratio good? We're a bit worried that it bloats the app and makes locating files harder in larger projects.

Also the current standard is using -test.ios (see jest-expo), so there's also a compatibility issue (what is someone wants a -test route?)

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Hi @OoDeLally, thanks for sharing the reproducible example. It was very helpful!

You're getting the error following the first approach from the Unit Testing guide because any file inside the app directory is considered to be part of the bundle when using the Expo Router library. In other words, the library doesn't ignore the *.test.* file pattern. This is also why the second approach works, where the test files are not included in the app directory.

You'll have to continue using the second approach and only include test files outside the app directory. Meanwhile, we'll call this out in our docs so that any subsequent developers are mindful of this issue and also look into respect patterns specified by Jest on the library level.

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