How to set BASE_URL environment variable in dockerized integration tests?

[Kolobamanacas]

I'm using dockerized Nest.js application with integration tests written with Vitest. After upgrade of all the packages to the latest versions I face an issue I don't understand how to solve. My packages versions are:

@nestjs/core: 10.3.8
typescript:   5.4.5
vitest:       1.6.0

The issue I have is TypeError: Invalid URL... Serialized Error: { code: 'ERR_INVALID_URL', input: '/' } error thrown by nestjs-url-generator. It eventually happens because in tests a BASE_URL environment variable is set to / instead of http://localhost as it should be and as it set as an environment variable in docker-compose.yml file for the particular service.

Massive abuse of console.log() shows that during vitest's global setup, process.env.BASE_URL returns correct value http://localhost, but as soon as any testfile runs the BASE_URL's value is reset to /.

So it seems like Vite resets existing value of BASE_URL. I thought that if that's the case I could just reset it back in my vitest-integration.config.ts file as it described in the docs (link1, link2) like this:

import { defineConfig, UserConfigExport } from 'vitest/config'

export default (): UserConfigExport => {
  return defineConfig({
    base: 'http://localhost', // <= I set new value for BASE_URL here.
  })
}

But that literally didn't change anything. So my question is: (best scenario) how do I force Vite to read existing value of BASE_URL from docker-compose.yml? Or, if that's not possible, how do I set any other value to BASE_URL other than default /? And lastly, if you also explain why in the world Vite replaces existing pre-defined environment variable I would really appreciate that. Thanks.

[hi-ogawa]

This seems like an unfortunate side effect from Vite. It looks like I can still overwrite it from test.env config. How about something like this?
https://stackblitz.com/edit/vitest-dev-vitest-f5v5k7?file=vite.config.ts

export default defineConfig({
  test: {
    env: {
      BASE_URL: process.env['BASE_URL'] ?? 'hello!',
    },
  },
});

It's certainly inconvenient but this BASE_URL convention seems deeply tied to Vite, so I'm not sure how much Vitest can manipulate that without breaking something.

[Kolobamanacas]

A bit hackish, but it works and seems like it didn't brake anything. Thanks! )