How to test (or lock) a module when there is an import of constants from external files (NodeJS, ExpressJS, NestJS)?

Question

Software testing

I'm trying to write an e2e application test on Nest ( https://nestjs.com/ ) - an add-on for ExpressJS.

Here is one of the modules:

import {Module} from '@nestjs/common';
import {DatabaseService} from './database.service';
import {config} from "../configuration";
import {SharedModule} from "../shared/shared.module";

const pgp = require('pg-promise')();
const db = pgp({
    host: config.database.host,
    ...
});

const connectionProvider = { provide: 'DatabaseToken', useValue: db };

@Module({
    components: [DatabaseService, connectionProvider],
    exports: [DatabaseService],
    imports: [SharedModule]
})
export class DatabaseModule {}

This is what the test looks like:

import * as express from 'express';
import * as request from 'supertest';
import { Test } from '@nestjs/testing';
import {AppModule} from "../src/app.module";

describe('Application', () => {
    const server = express();
    
    beforeAll(async () => {
        const module = await Test.createTestingModule({
            imports: [AppModule],
        }).compile();

        const app = module.createNestApplication(server);
        await app.init();
    });

    it(`/GET area`, () => {
        return request(server)
            .get('/area')
            .expect(200)
            .expect({
                data: {}
            });
    });
});

When running the test, an error occurs:

TypeError: Cannot read property 'host' of undefined

I tried to lock the import of the constant:

jest.mock('../configuration', () => ({
            database: {
                host: ''
            },
        }));

But the result is the same. Either I did not write the test correctly, or an error in the architecture.