SyntaxError: Identifier 'jest' has already been declared

[cnolimit]

If you are reporting a bug, please fill in below. Otherwise feel free to remove this template entirely.

Can you reproduce the problem with latest npm?

Yes after updating to the latest version the issue still occurs

###Can you still reproduce it?

Yes issue still occurs

Description

An issue with running test using jest v18.0.0

Expected behavior

The declared variable within the test.js file would be the first instance, or the jest global variable to be available within the test.js

Actual behavior

Error is logged, stating that jest has already been declared

Environment

Run these commands in the project folder and fill in their results:

1. npm ls react-scripts (if you haven’t ejected):
2. node -v7.3.0:
3. npm -3.10.10:

Then, specify:

1. Operating system: macOs Sierra
2. Browser and version: Chrome Version 55.0.2883.95 (64-bit)

Reproducible Demo

To re-create the issue;

• run create-react-app
• npm run eject
• update jest version to 18.0.0
• npm run test

[gaearon]

Can you provide the relevant code?

[bondz]

See #1311

[cnolimit]

Great! thanks all working now!

[gaearon]

Could you clarify what was broken and how #1311 fixes this?

[bondz]

@gaearon jest@18 tries to run the file scripts/test.js as a test. It is configured to look for test files in src/, which it now also matches to scr/* making it look in the scripts folder.

[gaearon]

Aaaah. Thanks for explaining.