Error while running unit tests with Jest

[pq-artem-i]

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Example Code

import { OpenAIEmailProcessor } from '../../infrastructure/email/openai-email-processor';
import { OpenAIClient } from '../../infrastructure/openai/openai-client';
import { PromptFactory } from '../../infrastructure/openai/prompt-factory';

describe('OpenAIEmailProcessor', () => {
  let openAIEmailProcessor: OpenAIEmailProcessor;
  let mockClient: jest.Mocked<OpenAIClient>;
  let mockPromptFactory: jest.Mocked<PromptFactory>;

  beforeEach(() => {
    mockClient = new OpenAIClient() as jest.Mocked<OpenAIClient>;
    mockPromptFactory = new PromptFactory() as jest.Mocked<PromptFactory>;
    openAIEmailProcessor = new OpenAIEmailProcessor(mockClient, mockPromptFactory);
  });

  it('should process an email and invoke the OpenAI client with the generated prompt', async () => {
      //test
  });
});

Error:

 FAIL  src/test/unit/openai-email-processor.spec.ts
  ● Test suite failed to run

    Jest encountered an unexpected token

    Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.

    Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration.

    By default "node_modules" folder is ignored by transformers.

    Here's what you can do:
     • If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it.
     • If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript
     • To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
     • If you need a custom transformation specify a "transform" option in your config.
     • If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.

    You'll find more details and examples of these config options in the docs:
    https://jestjs.io/docs/configuration
    For information about custom transformations, see:
    https://jestjs.io/docs/code-transformation

    Details:

    /home/temez/WebstormProjects/protoq/cc-ai-backend-clean/node_modules/@langchain/core/prompts.js:1
    ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){export * from './dist/prompts/index.js'
                                                                                      ^^^^^^

    SyntaxError: Unexpected token 'export'

    > 1 | import { ChatPromptTemplate } from '@langchain/core/prompts';
        | ^
      2 |
      3 | import { Email } from '../../domain/common';
      4 | import { OpenAIEmailProcessor } from '../../infrastructure/email/openai-email-processor';

      at Runtime.createScriptFromCode (node_modules/jest-runtime/build/index.js:1728:14)
      at Object.<anonymous> (src/test/unit/openai-email-processor.spec.ts:1:1)

Description

• I'm trying to run this example test, and getting Jest error

System Info

Node.js: v20.14.0
OS: Ubuntu 22.04.4 LTS x86_64
@langchain/openai: ^0.2.4

[dosubot[bot]]

Hi @pq-artem-i! I'm here to help you with your issue. I'm a bot that can assist you in solving bugs, answering questions, and becoming a contributor.

To resolve the Jest error indicating an unexpected token 'export' when running your TypeScript unit tests, you need to ensure that Jest can handle ES module syntax. Here are the steps to configure Jest to work with ES modules:

1. Install ts-jest and necessary dependencies:

   npm install --save-dev ts-jest @types/jest

2. Create or update your Jest configuration (jest.config.cjs):

   /** @type {import('ts-jest').JestConfigWithTsJest} */
   module.exports = {
     preset: "ts-jest/presets/default-esm",
     testEnvironment: "node",
     modulePathIgnorePatterns: ["dist/", "docs/"],
     moduleNameMapper: {
       "^(\\.{1,2}/.*)\\.js$": "$1",
     },
     transform: {
       "^.+\\.tsx?$": ["ts-jest", { useESM: true }],
     },
     transformIgnorePatterns: [
       "/node_modules/",
       "\\.pnp\\.[^\\/]+$",
     ],
     setupFiles: ["dotenv/config"],
     testTimeout: 20000,
     collectCoverageFrom: ["src/**/*.ts"],
   };

3. Ensure your tsconfig.json is set up correctly:

   {
     "compilerOptions": {
       "target": "ES2021",
       "module": "ES2020",
       "moduleResolution": "nodenext",
       "esModuleInterop": true,
       "strict": true,
       "skipLibCheck": true,
       "forceConsistentCasingInFileNames": true
     },
     "include": ["src/**/*"],
     "exclude": ["node_modules", "dist", "docs"]
   }

These steps ensure that Jest uses ts-jest to transform your TypeScript files, allowing it to understand ES module syntax. This should resolve the Jest error related to the unexpected token 'export' ^[1][2].

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