[5.0.0-alpha.2] test files with same name are ignored

[daKmoR]

Having 2 test files
test/foo.test.js
test/sub/foo.test.js

each containing 1 test

Expected Behavior

2 tests are executed

Actual Behavior

1 test is executed

How Do We Reproduce?

git clone https://github.com/daKmoR/karma-webpack-issue-400.git
cd karma-webpack-issue-400
yarn install
yarn test

this will execute 1 test even though it should be 2.

Workaround: rename test/sub/foo.test.js to test/sub/foo2.test.js and it works as expected