Mono repo e2e testing issue

[SergiiVlasiuk]

I've got some topics where this question rised but no correct answer or fix.

If I try e2e tests in monorepo application they are failed because not resolved imports in main application.

I'm submitting a...

[ ] Regression 
[x ] Bug report
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead post your question on Stack Overflow.

Current behavior

• Use project example by link
• execute build npm i (it should be successful)
• start e2e tests npm run test:e2e

npm run test:e2e

> [email protected] test:e2e
> jest --config ./apps/04-monorepo-apps-libs/test/jest-e2e.json

 FAIL  apps/04-monorepo-apps-libs/test/app.e2e-spec.ts
  ● Test suite failed to run

    Cannot find module '@app/database' from 'app.module.ts'

      2 | import { AppController } from './app.controller';
      3 | import { AppService } from './app.service';
    > 4 | import { DatabaseModule } from '@app/database';
        | ^
      5 |
      6 | @Module({
      7 |   imports: [DatabaseModule],

      at Resolver.resolveModule (../../../node_modules/jest-resolve/build/index.js:259:17)
      at Object.<anonymous> (../src/app.module.ts:4:1)

Test Suites: 1 failed, 1 total

Expected behavior

My expectation is that test should not be failed because unresolved module dependency

import { DatabaseModule } from '@app/database';

because it was resolved at build time.

Minimal reproduction of the problem with instructions

• Use project example by link
  • it was generated by nest-cli
  • i faced with similar situation on different OS (mac windows10, ubuntu18) trying migrate my application to monorepo configuration
  • the project example is not mine but it was generated using nest-cli and perfectly demonstrates my issues also;
• execute build npm i (it should be successful)
• start e2e tests npm run test:e2e
  P.S.
  I tried reconfigure test/jest-e2e.json to fix the issue but unsuccessfully.

What is the motivation / use case for changing the behavior?

nest g lib SHARED_LIB

or

nest g app OTHER_APP_NAME

Environment

nest info

 _   _             _      ___  _____  _____  _     _____
| \ | |           | |    |_  |/  ___|/  __ \| |   |_   _|
|  \| |  ___  ___ | |_     | |\ `--. | /  \/| |     | |
| . ` | / _ \/ __|| __|    | | `--. \| |    | |     | |
| |\  ||  __/\__ \| |_ /\__/ //\__/ /| \__/\| |_____| |_
\_| \_/ \___||___/ \__|\____/ \____/  \____/\_____/\___/


[System Information]
OS Version     : macOS Catalina
NodeJS Version : v15.8.0
NPM Version    : 7.5.1

[Nest CLI]
Nest CLI Version : 6.14.0

[Nest Platform Information]
platform-express version : 6.7.2
common version           : 6.7.2
core version             : 6.7.2

[kamilmysliwiec]

You have to manually update your Jest configuration (for e2e tests) by updating the moduleNameMapper configuration. This may change in the future if we decide to merge this PR nestjs/schematics#532

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