How to unit test in js without altering source code for the tests' needs and to then automate handling based on results

Let's say with have the source code for a js page. Any js page not just one that would follow revealing module pattern or something like that. I want to test that.

From what I've seen from jasmine you can do that two ways - either in the browser which works perfectly fine or I can test it with node. If I test the code in the browser I can't integrate the results of the tests in the context of a larger build like a maven build.

If I try running the tests with node I have to import dependencies. Tried to add them with require but I'm either reading wrong or it does not work since I don't get variables which are not exported. And I don't want to pollute the source code with exports and rearranging its structure just to meet the needs of the tests.

How can I do all of these things simultaneously:
1) not alter source code
2) test said source code
3) automate handling based on the results of the test