TypeError: require(...) is not a function error

My Express App is
```js
// index.ts
import express from 'express';
const app = express();

app.get('/', (req, res) => {
res.status(200);
});
app.listen(3000);

export default app;
```

and test is
```js
import request from 'supertest';
import app from '../index';

describe('/', () => {
it ('header', (done) => {
request(app)
.get('/')
.then(response => {
console.log('response');
expect(response.status).toBe(200);
done();
})
.catch(err => {
console.log('response err', err);
})
});
});
```

### dependency list:
- "express": "^4.17.1",
- "jest": "^25.1.0"
- "supertest": "^4.0.2"
- "ts-jest": "^25.2.1"
- "typescript": "^3.8.3"
- ...

### babel.config.js
```js
{
"presets": [
"@babel/env",
"@babel/preset-typescript"
],
"plugins": [
"@babel/plugin-proposal-optional-chaining",
"@babel/plugin-proposal-object-rest-spread",
"@babel/plugin-proposal-class-properties",
"@babel/plugin-transform-runtime"
]
}
```

### jest.config.js
```js
module.exports = {
verbose: true,
browser: true,
collectCoverage: true,
testEnvironment: 'node',
testRegex: '(/test/.*\\.test.[jt]s)$',
transform: {
'^.+\\.ts$': 'ts-jest',
},
coverageReporters: ['text'],
globals: {
window: true
}
}
```

### tsconfig.json
```json
{
"compilerOptions": {
"module": "es2020",
"esModuleInterop": true,
"allowSyntheticDefaultImports": true,
"target": "es2020",
"noImplicitAny": true,
"moduleResolution": "node",
"sourceMap": true,
},
}
```

Run the test, after turn on the server
Here is result ...

and iconv-lite code line:

what is wrong?