Problems testing with Jest


Trying to test a custom widget I run into the following problem:

 ● Test suite failed to run
    SyntaxError: Invalid or unexpected token

       5 | import { MessageService } from '@theia/core';
       6 | import { Message } from '@theia/core/lib/browser';
    >  7 | const imageSrc = require('./../../../../applications/browser-app/assets/image.png');   

Running the app, the image is available but this should not matter for my simple test.
As far as I can understand the error is that the require keyword seems to be unknown. If I remove the line with require my simple test is successful but then I have no image.
Unfortunately I am quite new to the world of TS, jest and react so I do not know which module I need additionally to get the tests to run.
Here is part of my package.json:

 "dependencies": {
        "@theia/core": "1.40.0"
    "devDependencies": {
        "@testing-library/react": "^14.0.0",
        "@types/jest": "^26.0.20",
        "jest": "^26.6.3",
        "rimraf": "^2.7.1",
        "ts-jest": "^26.5.6",
        "ts-node": "^10.9.1",
        "typescript": "~4.5.5"
    "scripts": {     
        "test": "jest --config configs/jest.config.ts"     

and here is my jest.config.ts:

import type { Config } from '@jest/types';

export default async (): Promise<Config.InitialOptions> => ({
    preset: 'ts-jest',
    testMatch: ['**.test.ts'],
    rootDir: '../',
    transform: {
        '^.+\\.(ts)$': 'ts-jest'

and my tsconfig.json:

    "compilerOptions": {
        "skipLibCheck": true,
        "declaration": true,
        "declarationMap": true,
        "noImplicitAny": true,
        "noEmitOnError": false,
        "noImplicitThis": true,
        "noUnusedLocals": true,
        "strictNullChecks": true,
        "experimentalDecorators": true,
        "emitDecoratorMetadata": true,
        "downlevelIteration": true,
        "resolveJsonModule": true,
        "module": "commonjs",
        "moduleResolution": "node",
        "target": "ES2017",
        "jsx": "react",
        "lib": ["ES2017", "dom"],
        "sourceMap": true,
        "rootDir": "src",
        "outDir": "lib"
    "include": ["src"]

Thanks for helping.
Best regards,