Running Mocha tests with timeout never finishes

I'm having difficulties while executing test script on my node.js project using Mocha. Problem is that test script never finishes, unless I finish it manually (ctrl+c). This problem started after I added --timeout parameter to mocha.opts. Timeout is added because I use mock-mongoose library, where suggested timeout is 120000 ms. Here is my mocha.opts:

--require ts-node/register
--watch-extensions ts
--timeout 120000
tests/**/*.ts

Here's code example:

    it("POST '/route' should return OK", async () => {
        const result = await routeController.createSomething(data)
        expect(result.statusCode).is.equal(HttpStatus.OK)
    })

I also tried calling done() function, but still not helping. My project structure:

node_modules
src
--- source code...
tests
--- tests source...
package.json
package-lock.json
....

Test script: mocha --opts ./tests/mocha.opts

Thanks in advance!