Could not locate module in test using @app

Flavio Gomes da Silva Lisboa — Wed, 26 Jun 2024 16:58:39 +0000

I'm trying to work with tests in NestJS now and I couldn't move forward due to a problem with the location of the modules.
The application was already responding, the problems started when I tried to run the tests.

The first try gave me several errors like this:

Cannot find module 'src/common/dto/paginated-response.dto' from 'applications/applications.service.ts'

According my reading of Tejas, I understood that the problem was the relative path starting in 'src/...'.

Then, I read the tutorial by Amir Mustafa for converting the relative paths to absolute paths from the configuration.

After replacing the relative paths with the @app key, I got to run the application, but the tests failed again. This time, the errors were like this:

Cannot find module '@app/users/users.controller' from 'users/users.controller.spec.ts'

After reading the question/answer by dragons0458, I understood that I should to configure moduleNameMapper inside jest section of package.json. The section is so now:

  "jest": {
    "moduleFileExtensions": [
      "js",
      "json",
      "ts"
    ],
    "rootDir": "src",
    "testRegex": ".*\\.spec\\.ts$",
    "transform": {
      "^.+\\.(t|j)s$": "ts-jest"
    },
    "collectCoverageFrom": [
      "**/*.(t|j)s"
    ],
    "coverageDirectory": "../coverage",
    "testEnvironment": "node",
    "moduleNameMapper": {
      "^@app/(.*)": "<rootDir>./dist/$1"
    }
  }

The third try gave me new errors, below, but now I don't know what I should do. It looks to me that $1 in moduleNameMapper is not converted to path.

Configuration error:

    Could not locate module @app/gateways/gateways.controller mapped as:
    [MY HOME]/backend_nestjs/src/dist/$1.

    Please check your configuration for these entries:
    {
      "moduleNameMapper": {
        "/^@app\/(.*)/": "[MY HOME]/backend_nestjs/src/dist/$1"
      },
      "resolver": undefined
    }

      1 | import { Test, TestingModule } from '@nestjs/testing';
    > 2 | import { GatewaysController } from '@app/gateways/gateways.controller';
        | ^
      3 | import { GatewaysService } from '@app/gateways/gateways.service';
      4 |
      5 | describe('GatewaysController', () => {

      at createNoMappedModuleFoundError (../node_modules/jest-resolve/build/resolver.js:759:17)
      at Object.<anonymous> (gateways/gateways.controller.spec.ts:2:1)

The application is answering in 3000 port, but the tests (12 tests) fail. What is lacking for the correct configuration for modules?

I am pasting here two files that I think can help to understand my configuration:

tsconfig.json

{
  "compilerOptions": {
    "module": "commonjs",
    "declaration": true,
    "removeComments": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "allowSyntheticDefaultImports": true,
    "target": "ES2021",
    "sourceMap": true,
    "outDir": "./dist",
    "baseUrl": "./",
    "incremental": true,
    "skipLibCheck": true,
    "strictNullChecks": false,
    "noImplicitAny": true,
    "strictBindCallApply": false,
    "forceConsistentCasingInFileNames": false,
    "noFallthroughCasesInSwitch": false,
    "paths": {
      "@app/*": ["./src/*"]
    }
  }
}

jest-e2e.json

{
  "moduleFileExtensions": ["js", "json", "ts"],
  "rootDir": ".",
  "testEnvironment": "node",
  "testRegex": ".e2e-spec.ts$",
  "transform": {
    "^.+\\.(t|j)s$": "ts-jest"
  }
}

Thank you very much.

DEV Community: Flavio Gomes da Silva Lisboa

Could not locate module in test using @app