Is there a way to disable bundling for Karma tests in Angular?

I'm working on a big Angular project that has more than 4000 Unit Tests. Starting the tests takes round about 100 - 120 seconds before the first test begins to run. Presently, we use Karma and Jasmine for the tests.

Is there a way to disable bundling the project for the tests? Using Jest is maybe an alternative because it does not bundle the project. But when I want to use Jest I have to correct more than 800 tests.

Here are some additional Information about the used versions:

• Angular 7.2
• Karma 4.0
• Jasmine 3.4
• Webpack 4.29 (no custom webpack config)