testMatch not working as expected

🐛 Bug Report

The regex is not working as I expected within testMatch argument.

To Reproduce

Steps to reproduce the behavior:

I thought I was passing the argument incorrectly via CLI so I started messing with the defaults in jest itself and found something odd.

If I change the default testMatch to this, it still works: testMatch: ['**/?(*.)+(test).js'],

If I change it to this, it finds no tests: testMatch: ['**/?(*.)+test.js'],

Expected behavior

I would expect this to work, without adding a capturing group

In [REMOVED]
  107 files checked.
  testMatch: **/?(*.)+test.js - 0 matches
  testPathIgnorePatterns: /node_modules/ - 107 matches
Pattern:  - 0 matches

Link to repl or repo (highly encouraged)

N/A

Run npx envinfo --preset jest

Paste the results here:

  System:
    OS: macOS High Sierra 10.13.3
    CPU: x64 Intel(R) Core(TM) i7-4850HQ CPU @ 2.30GHz
  Binaries:
    Node: 8.10.0 - /usr/local/bin/node
    npm: 6.1.0 - /usr/local/bin/npm
  npmPackages:
    jest: ^23.3.0 => 23.4.0 

[Saibamen]

Similar: https://github.com/facebook/jest/issues/7441 and https://github.com/facebook/create-react-app/issues/5935

[Saibamen]

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